Maternal height and the risk of preterm birth and low birth weight: a systematic review and meta-analyses

Age- and height-dependent bias of underweight and overweight assessment standards for children and adolescents

Background

Precision in evaluating underweight and overweight status among children and adolescents is paramount for averting health and developmental issues. Existing standards for these assessments have faced scrutiny regarding their validity. This study investigates the age and height dependencies within the international standards set by the International Obesity Task Force (IOTF), relying on body mass index (BMI), and contrasts them with Japanese standards utilizing the percentage of overweight (POW).

Method

We scrutinized a comprehensive database comprising 7,863,520 children aged 5-17 years, sourced from the School Health Statistics Research initiative conducted by Japan's Ministry of Education, Culture, Sports, Science, and Technology. Employing the quantile regression method, we dissected the structure of weight-for-height distributions across different ages and sexes, quantifying the potentially biased assessments of underweight and overweight status by conventional criteria.

Results

Applying IOFT criteria for underweight assessment revealed pronounced height dependence in males aged 11-13 and females aged 10-11. Notably, a discernible bias emerged, wherein children in the lower 25th percentile were classified as underweight five times more frequently than those in the upper 25th percentile. Similarly, the overweight assessment displayed robust height dependence in males aged 8-11 and females aged 7-10, with children in the lower 25th percentile for height deemed obese four or five times more frequently than their counterparts in the upper 25th percentile. Furthermore, using the Japanese POW criteria for assessment revealed significant age dependence in addition to considerably underestimating the percentage of underweight and overweight cases under the age of seven. However, the height dependence for the POW criterion was smaller than the BMI criterion, and the difference between height classes was less than 3-fold.

Conclusion

Our findings underscore the intricacies of age-dependent changes in body composition during the growth process in children, emphasizing the absence of gold standards for assessing underweight and overweight. Careful judgment is crucial in cases of short or tall stature at the same age, surpassing sole reliance on conventional criteria results.

Maternal Height Is an Independent Risk of Adverse Outcomes in Women with Gestational Diabetes Mellitus

INTRODUCTION

Maternal height has been shown to be associated with adverse outcomes in women with gestational diabetes mellitus (GDM). The aim of this study is to evaluate the association between maternal height and adverse outcomes stratified for gestational weight gain (GWG) and pre-pregnancy body mass index (BMI) in women with GDM.

METHODS

We conducted a retrospective study that included 2048 women diagnosed with GDM during 24-28 gestational weeks from July 1, 2017, to June 30, 2018, in Zhejiang Province, China. Demographic data, maternal characteristics and pregnancy complications were extracted from medical records. Maternal height was divided into three categories by tertiles. Chi-square was used to evaluate categorical data while one-way ANOVA was utilized to analyze continuous variables. The relationship between maternal height and adverse outcomes was examined using logistic regression.

RESULTS

We found that shorter women had higher rates of low birth weight (LBW) (p = 0.003) and primary cesarean section (primary CS) (p < 0.001) while taller women had higher rates of abnormal neonatal ponderal index (p < 0.001), postpartum hemorrhage (p = 0.044) and macrosomia (p < 0.001). In taller women who had excess GWG, maternal height was positively associated with the risk of macrosomia (aOR 1.97, 95% CI 0.95-4.10). In shorter women who had inadequate GWG, maternal height was significantly associated with LBW (aOR 2.20, 95% CI 1.13-4.29) and primary CS (aOR 2.08, 95% CI 1.38-3.12). Maternal height was a protective factor of postpartum hemorrhage (aOR 0.15, 95% CI 0.03-0.72) in shorter women with excess GWG. In women with normal pre-pregnancy BMI, maternal height was positively associated with LBW (aOR 2.00, 95% CI 1.15-3.49) and primary CS (aOR 1.71, 95% CI 1.28-2.28) in shorter women while it was negatively associated with the risk of abnormal neonatal ponderal index in both shorter and taller women compared to average height women (aOR 0.71, 95% CI 0.55-0.92; aOR 0.66, 95% CI 0.51-0.85).

CONCLUSION

The association between maternal height and adverse pregnancy outcomes varies with pre-pregnancy BMI and GWG in GDM women. Taking maternal height, pre-pregnancy BMI and GWG into account and using personalized prenatal management may reduce the risk of adverse pregnancy outcomes in GDM.

The Born in Guangzhou Cohort Study enables generational genetic discoveries

Genomic research that targets large-scale, prospective birth cohorts constitutes an essential strategy for understanding the influence of genetics and environment on human health1. Nonetheless, such studies remain scarce, particularly in Asia. Here we present the phase I genome study of the Born in Guangzhou Cohort Study2 (BIGCS), which encompasses the sequencing and analysis of 4,053 Chinese individuals, primarily composed of trios or mother-infant duos residing in South China. Our analysis reveals novel genetic variants, a high-quality reference panel, and fine-scale local genetic structure within BIGCS. Notably, we identify previously unreported East Asian-specific genetic associations with maternal total bile acid, gestational weight gain and infant cord blood traits. Additionally, we observe prevalent age-specific genetic effects on lipid levels in mothers and infants. In an exploratory intergenerational Mendelian randomization analysis, we estimate the maternal putatively causal and fetal genetic effects of seven adult phenotypes on seven fetal growth-related measurements. These findings illuminate the genetic links between maternal and early-life traits in an East Asian population and lay the groundwork for future research into the intricate interplay of genetics, intrauterine exposures and early-life experiences in shaping long-term health.

Reconsidering the developmental origins of adult disease paradigm: The 'metabolic coordination of childbirth' hypothesis

In uncomplicated pregnancies, birthweight is inversely associated with adult non-communicable disease (NCD) risk. One proposed mechanism is maternal malnutrition during pregnancy. Another explanation is that shared genes link birthweight with NCDs. Both hypotheses are supported, but evolutionary perspectives address only the environmental pathway. We propose that genetic and environmental associations of birthweight with NCD risk reflect coordinated regulatory systems between mother and foetus, that evolved to reduce risks of obstructed labour. First, the foetus must tailor its growth to maternal metabolic signals, as it cannot predict the size of the birth canal from its own genome. Second, we predict that maternal alleles that promote placental nutrient supply have been selected to constrain foetal growth and gestation length when fetally expressed. Conversely, maternal alleles that increase birth canal size have been selected to promote foetal growth and gestation when fetally expressed. Evidence supports these hypotheses. These regulatory mechanisms may have undergone powerful selection as hominin neonates evolved larger size and encephalisation, since every mother is at risk of gestating a baby excessively for her pelvis. Our perspective can explain the inverse association of birthweight with NCD risk across most of the birthweight range: any constraint of birthweight, through plastic or genetic mechanisms, may reduce the capacity for homeostasis and increase NCD susceptibility. However, maternal obesity and diabetes can overwhelm this coordination system, challenging vaginal delivery while increasing offspring NCD risk. We argue that selection on viable vaginal delivery played an over-arching role in shaping the association of birthweight with NCD risk.

Critical research gaps in treating growth faltering in infants under 6 months: A systematic review and meta-analysis

In 2020, 149.2 million children worldwide under 5 years suffered from stunting, and 45.4 million experienced wasting. Many infants are born already stunted, while others are at high risk for growth faltering early after birth. Growth faltering is linked to transgenerational impacts of poverty and marginalization. Few interventions address growth faltering in infants under 6 months, despite a likely increasing prevalence due to the negative global economic impacts of the COVID-19 pandemic. Breastfeeding is a critical intervention to alleviate malnutrition and improve child health outcomes, but rarely receives adequate attention in growth faltering interventions. A systematic review and meta-analysis were undertaken to identify and evaluate interventions addressing growth faltering among infants under 6 months that employed supplemental milks. The review was carried out following guidelines from the USA National Academy of Medicine. A total of 10,405 references were identified, and after deduplication 7390 studies were screened for eligibility. Of these, 227 were assessed for full text eligibility and relevance. Two randomized controlled trials were ultimately included, which differed in inclusion criteria and methodology and had few shared outcomes. Both studies had small sample sizes, high attrition and high risk of bias. A Bangladeshi study (n = 153) found significantly higher rates of weight gain for F-100 and diluted F-100 (DF-100) compared with infant formula (IF), while a DRC trial (n = 146) did not find statistically significant differences in rate of weight gain for DF-100 compared with IF offered in the context of broader lactation and relactation support. The meta-analysis of rate of weight gain showed no statistical difference and some evidence of moderate heterogeneity. Few interventions address growth faltering among infants under 6 months. These studies have limited generalizability and have not comprehensively supported lactation. Greater investment is necessary to accelerate research that addresses growth faltering following a new research framework that calls for comprehensive lactation support.

Risk factors for preterm birth: an umbrella review of meta-analyses of observational studies

BACKGROUND

Preterm birth defined as delivery before 37 gestational weeks is a leading cause of neonatal and infant morbidity and mortality. The aim of this study is to summarize the evidence from meta-analyses of observational studies on risk factors associated with PTB, evaluate whether there are indications of biases in this literature, and identify which of the previously reported associations are supported by robust evidence.

METHODS

We searched PubMed and Scopus until February 2021, in order to identify meta-analyses examining associations between risk factors and PTB. For each meta-analysis, we estimated the summary effect size, the 95% confidence interval, the 95% prediction interval, the between-study heterogeneity, evidence of small-study effects, and evidence of excess-significance bias. Evidence was graded as robust, highly suggestive, suggestive, and weak.

RESULTS

Eighty-five eligible meta-analyses were identified, which included 1480 primary studies providing data on 166 associations, covering a wide range of comorbid diseases, obstetric and medical history, drugs, exposure to environmental agents, infections, and vaccines. Ninety-nine (59.3%) associations were significant at P < 0.05, while 41 (24.7%) were significant at P < 10-6. Ninety-one (54.8%) associations had large or very large heterogeneity. Evidence for small-study effects and excess significance bias was found in 37 (22.3%) and 12 (7.2%) associations, respectively. We evaluated all associations according to prespecified criteria. Seven risk factors provided robust evidence: amphetamine exposure, isolated single umbilical artery, maternal personality disorder, sleep-disordered breathing (SDB), prior induced termination of pregnancy with vacuum aspiration (I-TOP with VA), low gestational weight gain (GWG), and interpregnancy interval (IPI) following miscarriage < 6 months.

CONCLUSIONS

The results from the synthesis of observational studies suggest that seven risk factors for PTB are supported by robust evidence. Routine screening for sleep quality and mental health is currently lacking from prenatal visits and should be introduced. This assessment can promote the development and training of prediction models using robust risk factors that could improve risk stratification and guide cost-effective preventive strategies.

TRIAL REGISTRATION

PROSPERO 2021 CRD42021227296.

Effects of size at birth on health, growth and developmental outcomes in children up to age 18: an umbrella review

BACKGROUND

Size at birth, an indicator of intrauterine growth, has been studied extensively in relation to subsequent health, growth and developmental outcomes. Our umbrella review synthesises evidence from systematic reviews and meta-analyses on the effects of size at birth on subsequent health, growth and development in children and adolescents up to age 18, and identifies gaps.

METHODS

We searched five databases from inception to mid-July 2021 to identify eligible systematic reviews and meta-analyses. For each meta-analysis, we extracted data on the exposures and outcomes measured and the strength of the association.

FINDINGS

We screened 16 641 articles and identified 302 systematic reviews. The literature operationalised size at birth (birth weight and/or gestation) in 12 ways. There were 1041 meta-analyses of associations between size at birth and 67 outcomes. Thirteen outcomes had no meta-analysis.Small size at birth was examined for 50 outcomes and was associated with over half of these (32 of 50); continuous/post-term/large size at birth was examined for 35 outcomes and was consistently associated with 11 of the 35 outcomes. Seventy-three meta-analyses (in 11 reviews) compared risks by size for gestational age (GA), stratified by preterm and term. Prematurity mechanisms were the key aetiologies linked to mortality and cognitive development, while intrauterine growth restriction (IUGR), manifesting as small for GA, was primarily linked to underweight and stunting.

INTERPRETATION

Future reviews should use methodologically sound comparators to further understand aetiological mechanisms linking IUGR and prematurity to subsequent outcomes. Future research should focus on understudied exposures (large size at birth and size at birth stratified by gestation), gaps in outcomes (specifically those without reviews or meta-analysis and stratified by age group of children) and neglected populations.

PROSPERO REGISTRATION NUMBER

CRD42021268843.

The Association Between Maternal Short Stature and Neonatal Intensive Care Unit Admission: A Longitudinal Study in Sabah

BACKGROUND

The rising number of newborns requiring neonatal intensive care unit (NICU) care poses immediate threats to their health and places emotional and financial burdens on families and healthcare systems. This study investigates the direct effect of maternal short stature on NICU admission in Sabah, Malaysia.

METHODS

A longitudinal study at Hospital Wanita Dan Kanak-Kanak Sabah (HWKKS) from 2018 to 2022 included 254 Malaysian women with singleton pregnancies and neonates born after the 37th week, excluding significant disorders, smoking/alcohol use, fetal death, and malformations. Birth weight, gestational age, and neonatal condition were recorded. The association between maternal height, low birth weight (LBW), and NICU admission was analyzed.

RESULTS

LBW prevalence was 15.35%, with an average participant height of 147.37 cm. Maternal stature was significantly associated with LBW, with the shortest quartile (Q1) having the highest risk. LBW was significantly associated with NICU admission, with LBW newborns at a sixfold higher risk. Maternal height was also significantly associated with NICU admission, with Q1 having the highest risk. The receiver operating characteristic (ROC) curve suggested combining Q1 and Q2 for the best prediction of NICU admission, indicating that shorter mothers face a higher risk of neonates requiring NICU care.

CONCLUSION

Maternal short stature could be a valuable predictor of LBW and NICU admission risk. It may be a screening tool to assess these risks in healthcare settings. However, further research is needed to explore this association's underlying mechanisms and potential interventions.

Vaginal delivery rate by near delivery sonographic weight estimation and maternal stature among nulliparous women

BACKGROUND

We evaluated the risk for cesarean delivery among term nulliparous women, categorized by maternal stature and recent sonographic estimated fetal weight (EFW).

METHODS

A retrospective study including singleton deliveries of nulliparous women between 2011 and 2020, with sonographic EFW within 1 week of delivery. We categorized maternal height into five groups: ≤150, 151-155, 156-160, 161-165, and ≥166 cm. Fetal weight estimation was categorized into five groups as well: ≤2500 g, 2501-2999, 3000-3499, 3500-3999, and ≥4000 g.

RESULTS

Overall, 13 107 deliveries were included. The cesarean delivery rate was inversely correlated with maternal height, ranging from 41.0% in group 1 to 13.1% in group 5. The vaginal delivery rate ranged from 33.3% in maternal height group 1 with EFW of ≥4000 g to 85% in maternal height group 5 with EFW of ≤2500 g. In weight categories above 2500 g, maternal height correlated significantly with vaginal delivery rate, except in weight category ≥4000 g in which vaginal delivery rate ranged around 30% in maternal height categories 1-3 and increased significantly in groups 4-5 to 50-60%. In multivariable logistic regression analysis, EFW was independently associated with CD for EFW categories 3500-3999 and ≥4000 g [aOR 95% CI 1.49 (1.08-2.06) and 4.39 (2.97-6.50), respectively]. Maternal height was negatively associated with CD [aOR 95% CI 0.67 (0.64-0.70)] for each increase in maternal height group.

CONCLUSIONS

Cesarean delivery rate was inversely correlated with maternal height, ranging from 41.0% among women ≤150 cm to 13.1% among women ≥166 cm. Maternal height and EFW of ≥3500 g are independently associated with CD rates among term nulliparous women.

Correlates of low birth weight and preterm birth in India

BACKGROUND

In the 21st century, India is still struggling to reduce the burden of malnutrition and child mortality, which is much higher than the neighbouring countries such as Nepal and Shri Lanka. Preterm birth (PTB) and low birth weight (LBW) predispose early-age growth faltering and premature mortality among children below the age of five. Thus, highlighting the determinants of LBW and PTB is necessary to achieve sustainable development goals.

OBJECTIVE

The present study provides macro-level estimates of PTB and LBW and aims to highlight the nature of the association between various demographic, socioeconomic, and maternal obstetric variables with these outcomes using a nationally representative dataset.

METHODS

Data on 170,253 most recent births from the National Family health survey (NFHS-5) 2019-21 was used for the analysis. The estimates of PTB and LBW are measured by applying sample weights. The correlates of LBW and PTB were analyzed using logistic models.

RESULTS

There were cross-state disparities in the prevalence of PTB and LBW. In India, an estimated 12% and 18% of children were LBW and PTB, respectively, in 2019-21. Maternal obstetric and anthropometric factors such as lack of antenatal care, previous caesarean delivery, and short-stature mothers were associated positively with adverse birth outcomes such as LBW and PTB. However, a few correlates were found to be differently associated with PTB and LBW. Mothers belonging to richer wealth status had higher chances of having a preterm birth (OR = 1.16, 95% CI: 1.11-1.20) in comparison to poor mothers. In contrast, the odds of having LBW infants were found to be increased with the decreasing level of the mother's education and wealth quintile.

CONCLUSIONS

In India, PTB and LBW can be improved by strengthening existing ante-natal care services and evaluating the effects of the history of caesarean births on future pregnancies.

Biological and pathological mechanisms leading to the birth of a small vulnerable newborn

The pathway to a thriving newborn begins before conception and continues in utero with a healthy placenta and the right balance of nutrients and growth factors that are timed and sequenced alongside hormonal suppression of labour until a mature infant is ready for birth. Optimal nutrition that includes adequate quantities of quality protein, energy, essential fats, and an extensive range of vitamins and minerals not only supports fetal growth but could also prevent preterm birth by supporting the immune system and alleviating oxidative stress. Infection, illness, undernourishment, and harmful environmental exposures can alter this trajectory leading to an infant who is too small due to either poor growth during pregnancy or preterm birth. Systemic inflammation suppresses fetal growth by interfering with growth hormone and its regulation of insulin-like growth factors. Evidence supports the prevention and treatment of several maternal infections during pregnancy to improve newborn health. However, microbes, such as Ureaplasma species, which are able to ascend the cervix and cause membrane rupture and chorioamnionitis, require new strategies for detection and treatment. The surge in fetal cortisol late in pregnancy is essential to parturition at the right time, but acute or chronically high maternal cortisol levels caused by psychological or physical stress could also trigger labour onset prematurely. In every pathway to the small vulnerable newborn, there is a possibility to modify the course of pregnancy by supporting improved nutrition, protection against infection, holistic maternal wellness, and healthy environments.

The association between maternal stature and adverse birth outcomes and the modifying effect of race and ethnicity: a population-based retrospective cohort study

BACKGROUND

There are known differences in the risk of perinatal and maternal birth outcomes because of maternal factors, such as body mass index and maternal race. However, the association of maternal height with adverse birth outcomes and the potential differences in this relationship by race and ethnicity have been understudied.

OBJECTIVE

This study aimed to examine the association between maternal stature and adverse perinatal outcomes and the potential modification of the association by race and ethnicity.

STUDY DESIGN

This retrospective cohort study was conducted using data on all singleton births in the United States in 2016 and 2017 (N=7,361,713) obtained from the National Center for Health Statistics. Short and tall stature were defined as <10th and >90th percentiles of the maternal height distribution (<154.9 and >172.7 cm, respectively). Race and ethnicity categories included non-Hispanic White, non-Hispanic Black, American Indian or Alaskan Native Asian or Pacific Islander, and Hispanic. The primary outcomes were preterm birth (<37 weeks of gestation), perinatal death, and composite perinatal death or severe neonatal morbidity. Logistic regression was used to obtain adjusted odds ratios and 95% confidence intervals with adjustment for confounding by maternal age, body mass index, and other factors. Multiplicative and additive effect modifications by race and ethnicity were assessed.

RESULTS

The study population included 7,361,713 women with a singleton stillbirth or live birth. Short women had an increased risk of adverse outcomes, whereas tall women had a decreased risk relative to average-stature women. Short women had an increased risk of perinatal death and composite perinatal death or severe neonatal morbidity (adjusted odds ratios, 1.14 [95% confidence interval, 1.10-1.17] and 1.21 [95% confidence interval, 1.19-1.23], respectively). The association between short stature and perinatal death was attenuated in non-Hispanic Black women compared with non-Hispanic White women (adjusted odds ratio, 1.10 [95% confidence interval, 1.03-1.17] vs 1.26 [95% confidence interval, 1.19-1.33]). Compared with average-stature women, tall non-Hispanic White women had lower rates of preterm birth, perinatal death, and composite perinatal death or severe neonatal morbidity (adjusted odds ratios, 0.82 [95% confidence interval, 0.81-0.83], 0.95 [95% confidence interval, 0.91-1.00], and 0.90 [95% confidence interval, 0.88-0.93], respectively). The association between tall and average stature with perinatal death was reversed in Hispanic women (adjusted odds ratio, 1.27; 95% confidence interval, 1.12-1.44). Compared with average-stature women, all tall women had lower rates of preterm birth, particularly among non-Hispanic Black and Hispanic women.

CONCLUSION

Relative to average-stature women, short women have an increased risk of adverse perinatal outcomes across all race and ethnicity groups; these associations were attenuated in Hispanic women and for some adverse outcomes in non-Hispanic Black and Asian women. Tall mothers have a lower risk of preterm birth in all racial and ethnic groups, whereas tall non-Hispanic White mothers have a lower risk of perinatal death or severe neonatal morbidity compared with average-stature women.

Does maternal stature modify the association between infants who are small or large for gestational age and adverse perinatal outcomes? A retrospective cohort study

OBJECTIVE

To investigate the effect of maternal stature on adverse birth outcomes and quantify perinatal risks associated with small- and large-for-gestational age infants (SGA and LGA, respectively) born to mothers of short, average, and tall stature.

DESIGN

Retrospective cohort study.

SETTING

USA, 2016-2017.

POPULATION

Women with a singleton live birth (N = 7 325 741).

METHODS

Using data from the National Center for Health Statistics, short and tall stature were defined as <10th and >90th centile of the maternal height distribution. Modified Poisson regression was used to estimate adjusted risk ratios (aRRs) and 95% confidence intervals (95% CIs).

MAIN OUTCOME MEASURES

Preterm birth (<37 weeks of gestation), neonatal intensive care unit (NICU) admission and severe neonatal morbidity/mortality (SNMM).

RESULTS

With increased maternal height, the risk of adverse outcomes increased in SGA infants and decreased in LGA infants compared with infants appropriate-for-gestational age (AGA) (p < 0.001). Infants who were SGA born to women of tall stature had the highest risk of NICU admission (aRR 1.98, 95% CI 1.91-2.05; p < 0.001), whereas LGA infants born to women of tall stature had the lowest risk (aRR 0.85, 95% CI 0.82-0.88; p < 0.001), compared with AGA infants born to women of average stature. LGA infants born to women of short stature had an increased risk of NICU admission and SNMM, compared with AGA infants born to women of average stature (aRR 1.32, 95% CI 1.27-1.38; aRR 1.21, 95% CI 1.13-1.29, respectively).

CONCLUSIONS

Maternal height modifies the association between SGA and LGA status at birth and neonatal outcomes. This quantification of risk can assist healthcare providers in monitoring fetal growth, and optimising neonatal care and follow-up.

Relationship between Birth Order and Postnatal Growth until 4 Years of Age: The Japan Environment and Children’s Study

Later-borns tend to be shorter than first-borns in childhood and adulthood. However, large-scale prospective studies examining growth during infancy according to birth order are limited. We aimed to investigate the relationship between birth order and growth during the first 4 years of life in a Japanese prospective birth cohort study. A total of 26,249 full-term singleton births were targeted. General linear and multivariable logistic regression models were performed and adjusted for birth weight, parents’ heights, maternal age at delivery, gestational weight gain, maternal smoking and alcohol drinking status during pregnancy, household income, breastfeeding status, and Study Areas. The multivariate adjusted mean length Z-scores in “first-borns having no sibling”, “first-borns having siblings”, “second-borns”, and “third-borns or more” were −0.026, −0.013, 0.136, and 0.120 at birth and −0.324, −0.330, −0.466, and −0.569 at 10 months, respectively. Results similar to those at 10 months were observed at 1.5, 3, and 4 years. The adjusted odds ratios (95% confidence intervals) of short stature at 4 years in “first-borns having siblings”, “second-borns”, and “third-borns or more” were 1.08 (0.84–1.39), 1.36 (1.13–1.62), and 1.50 (1.20–1.88), respectively, versus “first-borns having no sibling”. Birth order was significantly associated with postnatal growth and may be a factor predisposing to short stature in early childhood.

Risk factors for preterm labor: An Umbrella Review of meta-analyses of observational studies

Preterm birth defined as delivery before 37 gestational weeks, is a leading cause of neonatal and infant morbidity and mortality. Understanding its multifactorial nature may improve prediction, prevention and the clinical management. We performed an umbrella review to summarize the evidence from meta-analyses of observational studies on risks factors associated with PTB, evaluate whether there are indications of biases in this literature and identify which of the previously reported associations are supported by robust evidence. We included 1511 primary studies providing data on 170 associations, covering a wide range of comorbid diseases, obstetric and medical history, drugs, exposure to environmental agents, infections and vaccines. Only seven risk factors provided robust evidence. The results from synthesis of observational studies suggests that sleep quality and mental health, risk factors with robust evidence should be routinely screened in clinical practice, should be tested in large randomized trial. Identification of risk factors with robust evidence will promote the development and training of prediction models that could improve public health, in a way that offers new perspectives in health professionals.

Relationship between low birth weight and infant mortality: evidence from National Family Health Survey 2019-21, India

BACKGROUND

Low birth weight (LBW) predisposes physical and mental growth failure and premature death among infants. Studies report that LBW predominately explains infant mortality. However, existing studies rarely demonstrate the phenomenon of both observed and unobserved factors, which may influence the likelihood of birth and mortality outcomes simultaneously. In this study, we identified the spatial clustering of the prevalence of LBW along with its determinants. Further, the relationship between of LBW and infant mortality, considering the unobserved factors, has been explored in the study.

METHODS

Data for this study have been extracted from the National Family Health Survey (NFHS) round 5, 2019-21. We used the directed acyclic graph model to identify the potential predictors of LBW and infant mortality. Moran's I statistics have been used to identify the high-risk areas of LBW. We applied conditional mixed process modelling in Stata software to account for the simultaneous nature of occurrences of the outcomes. The final model has been performed after imputing the missing data of LBW.

RESULTS

Overall, in India, 53% of the mothers reported their babies' birth weight by seeing health card, 36% reported by recall, and about 10% of the LBW information was observed as missing. The state/union territory of Punjab and Delhi were observed to have the highest levels of LBW (about 22%) which is much higher than the national level (18%). The effect of LBW was more than four times larger compared to the effect in the analysis which does not account for the simultaneous occurrence of LBW and infant mortality (marginal effect; from 12 to 53%). Also, in a separate analysis, the imputation technique has been used to address the missing data. Covariates' effects showed that female children, higher order births, births that occur in Muslim and non-poor families and literate mothers were negatively associated with infant mortality. However, a significant difference was observed in the impact of LBW before and after imputing the missing values.

CONCLUSIONS

The current findings showed the significant association of LBW with infant deaths, highlighting the importance of prioritising policies that help improve the birth weight of new-born children that may significantly reduce the infant mortality in India.

Dose-response relationships of maternal height and weight with risk of low birthweight neonates: a meta-analysis

INTRODUCTION

The development of novel methods to identify pregnant women at increased risk of low birthweight neonates before delivery is required to improve pre- and periconceptional strategies to reduce the prevalence of low birthweight neonates. A dose-response meta-analysis was performed to examine the adjusted relationships of maternal height and weight with risk of low birthweight neonates.

EVIDENCE ACQUISITION

PubMed (Medline), CINAHL, PsycINFO, Wiley Online Library, ProQuest, Web of Science, Google Scholar, and Sage Journals Online were searched. There were no restrictions regarding publication date. English-language cohort studies involving singleton births that provided adjusted relative risks or Odds Ratios for low birthweight neonates at two or more values of maternal height or weight compared to the reference and numbers of low birthweight neonates and numbers of normal birthweight neonates in these values and the reference are included.

EVIDENCE SYNTHESIS

From the five finally eligible studies, four good-quality studies evaluating the relationship of maternal height with risk of low birthweight neonates and three good-quality studies evaluating the relationship of maternal weight with risk of low birthweight neonates were extracted. Both of these relationships were non-linear rather than linear (P values for non-linearity <0.05). Based on the non-linear dose-response model, maternal height limited to below 160 cm and maternal weight with no restrictions regarding the range were significantly and negatively related to risk of low birthweight neonates.

CONCLUSIONS

Risk of low birthweight neonates may decrease with increasing maternal height from below 160 cm to 160 cm and by increasing maternal weight regardless of above or below 55 kg.

Role of fetal head-circumference-to-maternal-height ratio in predicting Cesarean section for labor dystocia: prospective multicenter study

OBJECTIVE

To evaluate the relationship between the fetal head-circumference-to-maternal-height (HC/MH) ratio measured shortly before delivery and the occurrence of Cesarean section (CS) for labor dystocia.

METHODS

This was a multicenter prospective cohort study involving four tertiary maternity hospitals. An unselected cohort of women with a singleton fetus in cephalic presentation, at a gestational age beyond 36 + 0 weeks and without any contraindication for vaginal delivery, was enrolled between September 2020 and November 2021. The MH and fetal HC were measured on admission of the patient to the labor ward. The primary outcome of the study was the performance of the HC/MH ratio in the prediction of CS for labor dystocia. Women who underwent CS for any indication other than failed labor progression, including fetal distress, were excluded from the final analysis.

RESULTS

A total of 783 women were included in the study. Vaginal delivery occurred in 744 (95.0%) women and CS for labor dystocia in 39 (5.0%). CS for labor dystocia was associated with shorter MH (mean ± SD, 160.4 ± 6.6 vs 164.5 ± 6.3 cm; P < 0.001), larger fetal HC (339.6 ± 9.5 vs 330.7 ± 13.0 mm; P < 0.001) and a higher HC/MH ratio (2.12 ± 0.11 vs 2.01 ± 0.10; P < 0.001) compared with vaginal delivery. Multivariate logistic regression analysis showed that the HC/MH ratio was associated independently with CS for labor dystocia (adjusted odds ratio, 2.65 (95% CI, 1.85-3.79); P < 0.001). The HC/MH ratio had an area under the receiver-operating-characteristics curve of 0.77 and an optimal cut-off value for discriminating between vaginal delivery and CS for labor dystocia of 2.09, which was associated with a sensitivity of 0.62 (95% CI, 0.45-0.77), specificity of 0.79 (95% CI, 0.76-0.82), positive predictive value of 0.13 (95% CI, 0.09-0.19) and negative predictive value of 0.98 (95% CI, 0.96-0.99).

CONCLUSIONS

In a large cohort of unselected pregnancies, the HC/MH ratio performed better than did fetal HC and MH alone in identifying those cases that will undergo CS for labor dystocia, albeit with moderate predictive value. The HC/MH ratio could assist in the evaluation of women at risk for CS for labor dystocia. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

The influence of acculturation on the risk of preterm birth and low birthweight in migrant women residing in Western Australia

BACKGROUND

The risk of preterm birth (PTB) and low birthweight (LBW) may change over time the longer that immigrants reside in their adopted countries. We aimed to study the influence of acculturation on the risk of these outcomes in Australia.

METHODS

A retrospective cohort study using linked health data for all non-Indigenous births from 2005-2013 in Western Australia was undertaken. Acculturation was assessed through age on arrival, length of residence, interpreter use and having an Australian-born partner. Adjusted odds ratios (aOR) for term-LBW and PTB (all, spontaneous, medically-indicated) were calculated using multivariable logistic regression in migrants from six ethnicities (white, Asian, Indian, African, Māori, and 'other') for different levels of acculturation, compared to the Australian-born population as the reference.

RESULTS

The least acculturated migrant women, those from non-white non-Māori ethnic backgrounds who immigrated at age ≥18 years, had an overseas-born partner, lived in Australia for < 5 years and used a paid interpreter, had 58% (aOR 1.58, 95% CI 1.15-2.18) higher the risk of term-LBW and 40% (aOR 0.60, 95% CI 0.45-0.80) lower risk of spontaneous PTB compared to the Australian-born women. The most acculturated migrant women, those from non-white non-Māori ethnic backgrounds who immigrated at age <18 years, had an Australian-born partner, lived in Australia for > 10 years and did not use an interpreter, had similar risk of term-LBW but 43% (aOR 1.43, 95% CI 1.14-1.78) higher risk of spontaneous PTB than the Australian-born women.

CONCLUSION

Acculturation is an important factor to consider when providing antenatal care to prevent PTB and LBW in migrants. Acculturation may reduce the risk of term-LBW but, conversely, may increase the risk of spontaneous PTB in migrant women residing in Western Australia. However, the effect may vary by ethnicity and warrants further investigation to fully understand the processes involved.

Growth Patterns of Children With Short Stature in Adulthood According to Auxological Status and Maturity at Birth

CONTEXT

Prematurity carries a risk for impaired postnatal growth and long-term growth restriction. Especially children born SGA seem vulnerable for poor growth, as a persistent short stature can be observed in app 10-15% of these children.

OBJECTIVE

In this study we aimed to recognize differences in growth patterns of children according to sex, maturity, and auxological status at birth facilitating earlier identification of small-for-gestational-age (SGA) children with adult short stature.

METHODS

The growth data of 44 791 infants born between January 1, 1980, and December 30, 2012, among 2 pediatric cohorts with follow-up through December 31, 2020, were analyzed. A total of 5698 children with birth data had measurements at near final height (nfh) and at least 2 further points.

RESULTS

Preterm children (gestational age < 37 weeks) had a significantly lower mean nfh SDS than term children (preterm, -0.61; term, -0.18) and a higher likelihood of nfh < third percentile (preterm, 20.5%; term, 12.2%). SGA born children also had a lower mean nfh SD score (SDS) than children born appropriate for gestational age (AGA) (SGA, -1.06; AGA, -0.15) and a higher likelihood of nfh < third percentile (SGA, 28.2%; AGA 10.1%). Of 1204 SGA children, 672 (56%) showed successful catch-up growth (CUG) to nfh greater than or equal to the 10th percentile (SGA-CU), and 532 children (44%) did not (SGA-S). The difference in their mean nfh SDS (SGA-CU, -0.12; SGA-S -2.26) can only partly be explained by the differences in mean mid-parental height SDS (SGA-CU, -0.3; SGA-S, -1.19). During the first year, SGA-CU showed higher CUG (SGA-CU, +1.2 SDS; SGA-S, +0.45 SDS), which helps to discriminate between groups earlier.

CONCLUSION

Final growth outcome was influenced by prematurity and auxological status at birth, but not by sex. Height/length SDS increments during year 1 are instrumental to discern SGA children with later normal or short stature. While observing CUG until year 2 and 3 can add specificity, discrimination thereafter becomes difficult.

Vaginal and oral probiotics effect in the prevention of preterm delivery in patients visiting Kamali Hospital, Karaj, Iran in 2020

INTRODUCTION

The prevalence of preterm labor (PTL) is growing, and annually one in ten babies is born prematurely. Various studies have examined the effect of oral or vaginal probiotics on the prevention of preterm labor, which has yielded contrasting results. This study aimed to compare the impact of vaginal and oral probiotics on the prevention of preterm delivery.

METHODS

This clinical trial was performed among 185 pregnant women with a gestational age greater than or equal to 25 weeks visiting Kamali Hospital, Karaj, Iran in 2020. The participants were divided into three groups; intervention group 1 receiving Oral probiotic pill once a day until 37 weeks of pregnancy, intervention group 2 receiving probiotic vaginal suppository once a day until 37 weeks of pregnancy, and control group not receiving any intervention. Patients were then followed up until the end of pregnancy.

RESULTS

Demographic characteristics and gestational age at the time of intervention were not significantly different among the three groups. Overall, 26.7 % in the control group, 30 % in intervention group 1 %, and 22.5 % in intervention group 2 had deliveries less than 37 weeks. There was no significant difference in the frequency of preterm labor and the duration of pregnancy among the groups (all p > 0.05).

CONCLUSION

Probiotics use does not increase the rate of preterm delivery or reduce the duration of pregnancy, but the rate of preterm delivery was lower in the oral probiotic group. Further clinical studies on the impact of probiotics on PTL can yield valuable results.

Early arrivals: association of maternal obstetric factors with preterm births and their survival in India

OBJECTIVES

Preterm birth (PTB) increases the risk of various acute and chronic morbidities and premature mortality in children under 5 years of age. The present study examines the association between different maternal obstetric factors and PTB. In addition, this study estimates the risk of neonatal mortality among children born preterm.

STUDY DESIGN

Retrospective two-stage stratified sample design.

METHODS

The weighted prevalence of PTB was estimated using data on 148,746 most recent institutional births from the National Family Health Survey (NFHS)-4, 2015-16. The Poisson regression model was used to investigate the association between maternal obstetric factors and PTB. Using Cox's proportional hazard model, the risk of neonatal mortality among PTBs was estimated.

RESULTS

Maternal obstetric factors, such as minimal antenatal care, delivery complications, history of previous caesarean delivery and delivery at private health facilities, were significantly associated with an increased risk of PTB. The survival probability of preterm babies sharply declined in the first week of life and thereafter was found to stabilise. The risk of mortality in the first 28 days of life increased 2.5-fold if the baby was born preterm. Optimising antenatal care was found to lower the likelihood of PTB and improve their chances of survival.

CONCLUSION

Antenatal care services and delivery care practices in private facilities were strongly associated with the incidence and survival of PTB. Evaluating associations of history of caesarean births on future pregnancies can help understand their deleterious effects on PTB. Affordable, accessible and available antenatal care services, in both public and private facilities, can increase the survival rates of PTBs.

Associations of maternal birth weight, childhood height, BMI, and change in height and BMI from childhood to pregnancy with risks of preterm delivery

BACKGROUND

It remains unknown whether maternal early life body size and changes in height and BMI from childhood to pregnancy are associated with risks of having a preterm delivery.

OBJECTIVES

We investigated whether a woman's birth weight, childhood height, BMI, and changes in height and BMI from childhood to pregnancy were associated with preterm delivery.

METHODS

We studied 47,947 nulliparous women born from 1940 to 1996 who were included in the Copenhagen School Health Records Register with information on birth weight and childhood heights and weights at ages 7 and/or 13 years. Gestational age was obtained from the Danish Birth Register, as was prepregnancy BMI, for 13,114 women. Deliveries were classified as very (22 to <32 weeks) or moderately (32 to <37 weeks) preterm. Risk ratios (RRs) and 95% CIs were estimated using binomial regression.

RESULTS

A woman's birth weight and childhood height were inversely associated with having very and moderately preterm delivery. Childhood BMI had a U-shaped association with having a very preterm delivery; at age 7 years, compared to a BMI z score of 0, the RRs were 1.31 (95% CI, 1.11-1.54) for a z score of -1 and 1.18 (95% CI, 1.01-1.38) for a z score of +1. Short stature in childhood and adulthood was associated with higher risks of very and moderately preterm delivery. Changing from a BMI at the 85th percentile at 7 years (US CDC reference) to a prepregnancy BMI of 22.5 kg/m2 was associated with RRs of 1.12 (95% CI, 0.91-1.37) and 0.88 (95% CI, 0.78-0.99) for very and moderately preterm delivery, respectively, compared to a reference woman at the 50th percentile at 7 years (22.5 kg/m2 prepregnancy BMI).

CONCLUSIONS

Maternal birth weight, childhood height, and BMI are associated with very and moderately preterm delivery, although in different patterns. Consistent short stature is associated with very and moderately preterm delivery, whereas normalizing BMI from childhood to pregnancy may reduce risks of having a very preterm delivery.

Effect of maternal height on the risk of caesarean section in singleton births: evidence from a large-scale survey in India

OBJECTIVE

This study examines the association of maternal height with caesarean section (CS) in India. It is hypothesised that maternal height has no significant effect on the risk of undergoing caesarean section.

DESIGN

A cross-sectional study based on a nationally representative large-scale survey data (National Family Health Survey-4), conducted in 2015-2016.

SETTING AND PARTICIPANTS

Analysis is based on 125 936 women age 15-49 years, having singleton live births. Logistic regression has been performed to determine the contribution of maternal height to the ORs of CS birth, adjusting for other exposures. Restricted cubic spline was used as a smooth function to model the non-linear relationship between height and CS. Height data were decomposed using the restricted cubic spline with five knots located at the 5th, 27.5th, 50th, 72.5th and 95th, percentiles.

PRIMARY AND SECONDARY OUTCOME MEASURES

The main outcome variable of interest in the study is CS. Maternal height is the key explanatory variable. Other explanatory variables are age, parity, sex of child, birth weight, wealth index, place of residence, place of child delivery and household health insurance status.

RESULTS

The results reveal that the odds of undergoing CS significantly decrease with increase in maternal heights. Mothers with a height of 120 cm (adjusted OR (AOR): 5.08; 95% CI 3.83 to 6.74) were five times more likely, while mothers with height of 180 cm were 23% less likely (AOR: 0.77; 95% CI 0.62 to 0.95) to undergo CS as compared with mothers with height of 150 cm.

CONCLUSIONS

Shorter maternal height is linked to a higher risk of CS. Our findings could be used to argue for policies that target stunting in infant girls and avoid unnecessary CS, as there is potential effect on growth during adolescence and early adulthood, with the goal to increase their adult heights, thereby lowering their risk of CS and adverse delivery outcomes.

Maternal-focused interventions to improve infant growth and nutritional status in low-middle income countries: A systematic review of reviews

BACKGROUND

Small and nutritionally at-risk infants under 6 months (<6m) are a vulnerable group at increased risk of mortality, morbidity, poor growth and sub-optimal development. Current national and international (World Health Organization) management guidelines focus mainly on infants' needs, yet growing evidence suggests that maternal factors also influence infant outcomes. We aimed to inform future guidelines by exploring the impacts of maternal-focused interventions on infant feeding and growth.

METHODS

We conducted a systematic review of reviews published since 2008 (PROSPERO, register number CRD 42019141724). We explored five databases and a wide variety of maternal-focused interventions based in low- and middle-income countries. Infant outcomes of interest included anthropometric status, birthweight, infant mortality, breastfeeding and complementary feeding practices. Given heterogenous interventions, we present a narrative synthesis of the extracted data.

RESULTS

We included a total of 55 systematic reviews. Numerous maternal interventions were effective in improving infant growth or feeding outcomes. These included breastfeeding promotion, education, support and counselling interventions. Maternal mental health, while under-researched, showed potential to positively impact infant growth. There was also some evidence for a positive impact of: women's empowerment, m-health technologies, conditional cash transfers, water, sanitation and hygiene and agricultural interventions. Effectiveness was increased when implemented as part of a multi-sectoral program. Antenatal supplementation with macronutrient, multiple micronutrients, Vitamin D, zinc, iron folic acid and possibly calcium, iodine and B12 in deficient women, improved birth outcomes. In contrast, evidence for postnatal supplementation was limited as was evidence directly focusing on small and nutritionally at-risk infants; most reviews focused on the prevention of growth faltering.

CONCLUSION

Our findings suggest sufficient evidence to justify greater inclusion of mothers in more holistic packages of care for small and nutritionally at-risk infants aged <6m. Context specific approaches are likely needed to support mother-infant dyads and ensure infants survive and thrive.

Prenatal and postnatal determinants of stunting at age 0-11 months: A cross-sectional study in Indonesia

Background

Childhood stunting remains the most challenging consequence of undernutrition because it is associated with suboptimal brain development and the subsequent increased risk of metabolic diseases and decreased earnings in adult life. The Sambas District in Indonesia has a high prevalence of stunting (28.4%), followed by underweight (25.5.%) and wasting (14.4%) among children, as well chronic energy deficiency (27%) and anemia (62%) among pregnant women. The present study sought to determine significant factors in childhood stunting with a focus on maternal and child nutrition and prenatal and postnatal determinants.

Methods

This prospective, repeat, cross-sectional study investigated factors associated with stunting among 559 infants age 0–11 months in Sambas District, Indonesia. Anthropometric measurements were performed by trained enumerators. Data from a 2016 survey of pregnant women and a 2017 survey on mothers and their children were used for postnatal data collection to quantify the prevalence of stunting at age 0–11 months. Using 20 potential predictors of stunting categorized by household characteristics, maternal characteristics, antenatal care services, and child characteristics, logistic regression analysis was conducted to assess the adjusted association between stunting and these factors.

Results

Of 559 children analyzed, 20.8% were stunted. In the model with low birth weight (LBW) as predictor for stunting, the odds of stunting increased significantly among children who weighed <2.500 g at birth; children who had diarrhea in the past 2 weeks and children who had incomplete basic immunization coverage as infants age 9–11 months. In model without LBW, the odds of stunting increased significantly among children who had preterm at birth, short maternal stature and children who had incomplete basic immunization coverage for 9–11 months infants.

Conclusions

Postnatal factors—preterm birth, low birth weight, diarrhea and complete basic immunization coverage—were associated with infant stunting in Sambas District, Indonesia. The prenatal factors such as short maternal stature were significant in the multivariate model. Policy makers, especially in the government, should recommend measures focused on those prenatal and postnatal factors to prevent stunting in children and to avoid the sequelae of childhood stunting in adult life.

Personalized assessment of cervical length improves prediction of spontaneous preterm birth: a standard and a percentile calculator

BACKGROUND

A sonographic short cervix (length <25 mm during midgestation) is the most powerful predictor of preterm birth. Current clinical practice assumes that the same cervical length cutoff value should apply to all women when screening for spontaneous preterm birth, yet this approach may be suboptimal.

OBJECTIVE

This study aimed to (1) create a customized cervical length standard that considers relevant maternal characteristics and gestational age at sonographic examination and (2) assess whether the customization of cervical length evaluation improves the prediction of spontaneous preterm birth.

STUDY DESIGN

This retrospective analysis comprises a cohort of 7826 pregnant women enrolled in a longitudinal protocol between January 2006 and April 2017 at the Detroit Medical Center. Study participants met the following inclusion criteria: singleton pregnancy, ≥1 transvaginal sonographic measurements of the cervix, delivery after 20 weeks of gestation, and available relevant demographics and obstetrical history information. Data from women without a history of preterm birth or cervical surgery who delivered at term without progesterone treatment (N=5188) were used to create a customized standard of cervical length. The prediction of the primary outcome, spontaneous preterm birth at <37 weeks of gestation, was assessed in a subset of pregnancies (N=7336) that excluded cases with induced labor before 37 weeks of gestation. Area under the receiver operating characteristic curve and sensitivity at a fixed false-positive rate were calculated for screening at 20 to 23 6/7, 24 to 27 6/7, 28 to 31 6/7, and 32 to 35 6/7 weeks of gestation in asymptomatic patients. Survival analysis was used to determine which method is better at predicting imminent delivery among symptomatic women.

RESULTS

The median cervical length remained fundamentally unchanged until 20 weeks of gestation and subsequently decreased nonlinearly with advancing gestational age among women who delivered at term. The effects of parity and maternal weight and height on the cervical length were dependent on the gestational age at ultrasound examination (interaction, P<.05 for all). Parous women had a longer cervix than nulliparous women, and the difference increased with advancing gestation after adjusting for maternal weight and height. Similarly, maternal weight was nonlinearly associated with a longer cervix, and the effect was greater later in gestation. The sensitivity at a 10% false-positive rate for prediction of spontaneous preterm birth at <37 weeks of gestation by a short cervix ranged from 29% to 40% throughout pregnancy, yet it increased to 50%, 50%, 53%, and 54% at 20 to 23 6/7, 24 to 27 6/7, 28 to 31 6/7, and 32 to 35 6/7 weeks of gestation, respectively, for a low, customized percentile (McNemar test, P<.001 for all). When a cervical length <25 mm was compared to the customized screening at 20 to 23 6/7 weeks of gestation by using a customized percentile cutoff value that ensured the same negative likelihood ratio for both screening methods, the customized approach had a significantly higher (about double) positive likelihood ratio in predicting spontaneous preterm birth at <33, <34, <35, <36, and <37 weeks of gestation. Among symptomatic women, the difference in survival between women with a customized cervical length percentile of ≥10th and those with a customized cervical length percentile of <10th was greater than the difference in survival between women with a cervical length ≥25 mm and those with a cervical length <25 mm.

CONCLUSION

Compared to the use of a cervical length <25 mm, a customized cervical length assessment (1) identifies more women at risk of spontaneous preterm birth and (2) improves the distinction between patients at risk for impending preterm birth in those who have an episode of preterm labor.

Association between maternal height and mode of delivery in nulliparous Japanese women

AIM

The primary aim of this study was to examine the association between maternal height and mode of delivery in nulliparous Japanese women. The secondary aim was to examine the association between maternal height and maternal and neonatal morbidities.

METHODS

This retrospective cohort study included women who gave birth at Osaka Women's and Children's Hospital, a tertiary perinatal center in Japan, from January 2015 to December 2017. Nulliparous Japanese women with singleton gestation, who went into labor at term were included in the study. The primary outcome was mode of delivery, and the secondary outcomes were maternal and neonatal morbidities. The relationships between maternal height and the outcomes were evaluated using multivariate logistic regression analysis adjusted for potential confounders. Maternal height was categorized into five groups with 5-cm increments for the analysis.

RESULTS

A total of 1593 women were analyzed in this study. Shorter women had higher rate of cesarean delivery (CD) than taller women. There were no significant differences in the rates of operative vaginal delivery, maternal morbidity and neonatal morbidity among the maternal-height groups. The adjusted odds ratios (95% confidential interval) of maternal heights of <150 cm, 150-154 cm, 160-164 cm and ≥165 cm for CD, compared with a maternal height of 155-159 cm, were 3.56 (1.79-7.09), 1.68 (1.06-2.64), 0.63 (0.40-1.00) and 0.57 (0.30-1.01), respectively.

CONCLUSION

Shorter nulliparous Japanese women were more likely to undergo intrapartum CD. However, the rates of maternal and neonatal morbidities in shorter women were similar to those in taller women.

Dissecting maternal and fetal genetic effects underlying the associations between maternal phenotypes, birth outcomes, and adult phenotypes: A mendelian-randomization and haplotype-based genetic score analysis in 10,734 mother-infant pairs

BACKGROUND

Many maternal traits are associated with a neonate's gestational duration, birth weight, and birth length. These birth outcomes are subsequently associated with late-onset health conditions. The causal mechanisms and the relative contributions of maternal and fetal genetic effects behind these observed associations are unresolved.

METHODS AND FINDINGS

Based on 10,734 mother-infant duos of European ancestry from the UK, Northern Europe, Australia, and North America, we constructed haplotype genetic scores using single-nucleotide polymorphisms (SNPs) known to be associated with adult height, body mass index (BMI), blood pressure (BP), fasting plasma glucose (FPG), and type 2 diabetes (T2D). Using these scores as genetic instruments, we estimated the maternal and fetal genetic effects underlying the observed associations between maternal phenotypes and pregnancy outcomes. We also used infant-specific birth weight genetic scores as instrument and examined the effects of fetal growth on pregnancy outcomes, maternal BP, and glucose levels during pregnancy. The maternal nontransmitted haplotype score for height was significantly associated with gestational duration (p = 2.2 × 10-4). Both maternal and paternal transmitted height haplotype scores were highly significantly associated with birth weight and length (p < 1 × 10-17). The maternal transmitted BMI scores were associated with birth weight with a significant maternal effect (p = 1.6 × 10-4). Both maternal and paternal transmitted BP scores were negatively associated with birth weight with a significant fetal effect (p = 9.4 × 10-3), whereas BP alleles were significantly associated with gestational duration and preterm birth through maternal effects (p = 3.3 × 10-2 and p = 4.5 × 10-3, respectively). The nontransmitted haplotype score for FPG was strongly associated with birth weight (p = 4.7 × 10-6); however, the glucose-increasing alleles in the fetus were associated with reduced birth weight through a fetal effect (p = 2.2 × 10-3). The haplotype scores for T2D were associated with birth weight in a similar way but with a weaker maternal effect (p = 6.4 × 10-3) and a stronger fetal effect (p = 1.3 × 10-5). The paternal transmitted birth weight score was significantly associated with reduced gestational duration (p = 1.8 × 10-4) and increased maternal systolic BP during pregnancy (p = 2.2 × 10-2). The major limitations of the study include missing and heterogenous phenotype data in some data sets and different instrumental strength of genetic scores for different phenotypic traits.

CONCLUSIONS

We found that both maternal height and fetal growth are important factors in shaping the duration of gestation: genetically elevated maternal height is associated with longer gestational duration, whereas alleles that increase fetal growth are associated with shorter gestational duration. Fetal growth is influenced by both maternal and fetal effects and can reciprocally influence maternal phenotypes: taller maternal stature, higher maternal BMI, and higher maternal blood glucose are associated with larger birth size through maternal effects; in the fetus, the height- and metabolic-risk-increasing alleles are associated with increased and decreased birth size, respectively; alleles raising birth weight in the fetus are associated with shorter gestational duration and higher maternal BP. These maternal and fetal genetic effects may explain the observed associations between the studied maternal phenotypes and birth outcomes, as well as the life-course associations between these birth outcomes and adult phenotypes.

Effect of a nutrient-rich, food-based supplement given to rural Vietnamese mothers prior to and/or during pregnancy on birth outcomes: A randomized controlled trial

Obtaining a nutrient-rich diet during pregnancy is a challenge for pregnant women living in low-income countries. This randomized, controlled trial was designed to determine if a freshly prepared food supplement from local animal-source foods and dark-green leafy vegetables given prior to and/or during pregnancy improved birth outcomes in rural Vietnamese women. Primiparous women, 18 to 30 years of age, who participated in the study were assigned to one of three groups: PC-T women received the supplement from pre-conception to term, MG-T women received the supplement from mid-gestation to term, and the RPC women received routine prenatal care. Supplement intake was observed and quantified. Infant anthropometry was measured at birth and/or within seven days of delivery. The effect of the intervention on maternal and birth outcomes was determined using linear regression modeling. Of the 460 women enrolled in the study, 317 women completed the study. Those not completing the study had either moved from the area, did not conceive within 12 months of study enrollment, or miscarried. The food-based supplement increased protein, iron, zinc, folate, vitamin A and B12 intakes in the PC-T and the MG-T groups. However, it failed to alter infant anthropometric measurements at birth. In the entire cohort, maternal gestational weight gain was greater in women with a low pre-pregnancy BMI (<18.5) and in women with a higher educational attainment. Working as a farmer reduced gestational weight gain but it did not affect birth weight or length. In summary, a nutrient-rich, food-based supplement given to rural Vietnamese women from pre-conception to term or mid-gestation to term did not affect maternal or infant outcomes. The low weight gains, possibly due to demanding farm work done throughout the reproductive cycle, may have obviated any effects of the low energy, nutrient-rich food supplement on birth outcomes.

Trial registration : Registered Clinical Trials.gov: NCT01235767.

Why and How Imprinted Genes Drive Fetal Programming

Imprinted genes mediate fetal and childhood growth and development, and early growth patterns drive fetal programming effects. However, predictions and evidence from the kinship theory of imprinting have yet to be directly integrated with data on fetal programming and risks of metabolic disease. I first define paternal-gene and maternal-gene optima with regard to early human growth and development. Next, I review salient evidence with regard to imprinted gene effects on birth weight, body composition, trajectories of feeding and growth, and timing of developmental stages, to evaluate why and how imprinted gene expression influences risks of metabolic disease in later life. I find that metabolic disease risks derive primarily from maternal gene biases that lead to reduced placental efficacy, low birth weight, low relative muscle mass, high relative white fat, increased abdominal adiposity, reduced pancreatic β-cell mass that promotes insulin resistance, reduced appetite and infant sucking efficacy, catch-up fat deposition from family foods after weaning, and early puberty. Paternal gene biases, by contrast, may contribute to metabolic disease via lower rates of brown fat thermiogenesis, and through favoring more rapid postnatal catch-up growth after intrauterine growth restriction from environmental causes. These disease risks can be alleviated through dietary and pharmacological alterations that selectively target imprinted gene expression and relevant metabolic pathways. The kinship theory of imprinting, and mother-offspring conflict more generally, provide a clear predictive framework for guiding future research on fetal programming and metabolic disease.

Relationship Between Prepregnancy Overweight, Obesity, and Preterm Birth in Puerto Rico

Objectives We examined the association between prepregnancy body mass index (PP-BMI) and preterm birth (PTB) among women in Puerto Rico (PR) as a potentially modifiable risk factor. Methods We conducted a retrospective study using the birth certificate data files from 2005 to 2012 developed by the PR Department of Health to examine the relationship between PP-BMI and PTB. Logistic regression was used to determine crude and adjusted odds ratios (OR) and 95% confidence intervals (CI) for the categories of PP-BMI of overweight (25-29.9 kg/m²), obesity (≥ 30 kg/m²), and overweight and obesity together (≥ 25 kg/m²) and PTB. Stratified analysis explored the associations between PP-BMI and PTB by region within PR and year. Results Following exclusions of birth records with missing data, 343,508 births were included in our analysis. The percentage of PTB decreased from 18.6 to 15.2 during our study period. Statistically significant differences were observed between preterm and full term births across all covariates. Overweight (OR 1.08, 95% CI 1.06, 1.11), obesity (OR 1.17, 95% CI 1.14, 1.20), and overweight and obesity together (OR 1.11, 95% CI 1.09, 1.14) were significantly associated with increased odds of PTB after adjusting for confounders. The associations between PP-BMI and PTB persisted across all regions and years. Conclusions for Practice PP-BMI is associated with increased odds of PTB among women in PR and the associations were consistent in exploratory analyses. Future research should examine the relationship between PP-BMI and PTB among other Hispanic subgroups and among Puerto Ricans in the mainland United States.

Trends in maternal prepregnancy body mass index (BMI) and its association with birth and maternal outcomes in California, 2007-2016: A retrospective cohort study

OBJECTIVE

To determine recent trends in maternal prepregnancy body mass index (BMI) and to quantify its association with birth and maternal outcomes.

METHODS

A population-based retrospective cohort study included resident women with singleton births in the California Birth Statistical Master Files (BSMF) database from 2007 to 2016. There were 4,621,082 women included out of 5,054,968 women registered in the database. 433,886 (8.6%) women were excluded due to invalid or missing information for BMI. Exposures were underweight (BMI < 18.5 kg/m2), normal weight (18.5-24.9 kg/m2), overweight (25.0-29.9 kg/m2), and obese (≥ 30 kg/m2) at the onset of pregnancy. Obesity was subcategorized into class I (30.0-34.9 kg/m2), class II (35.0-39.9 kg/m2), and class III (≥ 40 kg/m2), while adverse outcomes examined were low birth weight (LBW), very low birth weight (VLBW), macrosomic births, preterm birth (PTB), very preterm birth (VPTB), small-for-gestational-age birth (SGA), large-for-gestational-age birth (LGA), and cesarean delivery (CD). Descriptive analysis, simple linear regression, and multivariate logistic regression were performed, and adjusted odds ratios (AORs) with 95% confidence intervals (CIs) for associations were estimated.

RESULTS

Over the ten-year study period, the prevalence of underweight and normal weight women at time of birth declined by 10.6% and 9.7%, respectively, while the prevalence of overweight and obese increased by 4.3% and 22.9%, respectively. VLBW increased significantly with increasing BMI, by 24% in overweight women and by 76% in women with class III obesity from 2007 to 2016. Women with class III obesity also had a significant increase in macrosomic birth (170%) and were more likely to deliver PTB (33%), VPTB (66%), LGA (231%), and CD (208%) than women with a normal BMI. However, obese women were less likely to have SGA infants; underweight women were 51% more likely to have SGA infants than women with a normal BMI.

CONCLUSIONS

In California from 2007 to 2016, there was a declining trend in women with prepregnancy normal weight, and a rising trend in overweight and obese women, particularly obesity class III. Both extremes of prepregnancy BMI were associated with an increased incidence of adverse neonatal outcomes; however, the worse outcomes were prominent in those women classified as obese.

A large proportion of poor birth outcomes among Aboriginal Western Australians are attributable to smoking, alcohol and substance misuse, and assault

Background

Aboriginal infants have poorer birth outcomes than non-Aboriginal infants. Harmful use of tobacco, alcohol, and other substances is higher among Aboriginal women, as is violence, due to factors such as intergenerational trauma and poverty. We estimated the proportion of small for gestational age (SGA) births, preterm births, and perinatal deaths that could be attributed to these risks.

Methods

Birth, hospital, mental health, and death records for Aboriginal singleton infants born in Western Australia from 1998 to 2010 and their parents were linked. Using logistic regression with a generalized estimating equation approach, associations with birth outcomes and population attributable fractions were estimated after adjusting for demographic factors and maternal health during pregnancy.

Results

Of 28,119 births, 16% of infants were SGA, 13% were preterm, and 2% died perinatally. 51% of infants were exposed in utero to at least one of the risk factors and the fractions attributable to them were 37% (SGA), 16% (preterm) and 20% (perinatal death).

Conclusions

A large proportion of adverse outcomes were attributable to the modifiable risk factors of substance use and assault. Significant improvements in Aboriginal perinatal health are likely to follow reductions in these risk factors. These results highlight the importance of identifying and implementing risk reduction measures which are effective in, and supported by, Aboriginal women, families, and communities.

Electronic supplementary material

The online version of this article (10.1186/s12884-019-2252-4) contains supplementary material, which is available to authorized users.

Estimation of protein requirements in Indian pregnant women using a whole-body potassium counter

BACKGROUND

The 2007 World Health Organization/Food and Agriculture Organization/United Nations University (WHO/FAO/UNU) recommendation for the Estimated Average Requirement (EAR) of additional protein during pregnancy for a gestational weight gain (GWG) of 12 kg (recalculated from a GWG of 13.8 kg) is 6.7 and 21.7 g/d in the second and the third trimester, respectively. This EAR is based on measurements of potassium accretion in high-income country (HIC) pregnant women. It is not known if low- to middle-income country, but well-nourished, pregnant women have comparable requirements.

OBJECTIVE

We aimed to estimate total body potassium (TBK) accretion during pregnancy in Indian pregnant women, using a whole-body potassium counter (WBKC), to measure their additional protein EAR.

METHODS

Well-nourished pregnant women (20-40 y, n = 38, middle socioeconomic stratum) were recruited in the first trimester of pregnancy. Anthropometric, dietary, and physical activity measurements, and measurements of TBK using a WBKC, were performed at each trimester and at birth.

RESULTS

The mid-trimester weight gain was 2.7 kg and 8.0 kg in the second and the third trimester, respectively, for an average 37-wk GWG of 10.7 kg and a mean birth weight of 3.0 kg. Protein accretion was 2.7 and 5.7 g/d, for an EAR of 8.2 and 18.9 g/d in the second and the third trimester, respectively. The additional protein EAR, calculated for a GWG of 12 kg, was 9.1 and 21.2 g/d in the second and the third trimester, respectively.

CONCLUSION

The additional protein requirements of well-nourished Indian pregnant women for a GWG of 12 kg in the second and third trimesters were similar to the recalculated 2007 WHO/FAO/UNU requirements for 12 kg.

Association between adolescent pregnancy and adverse birth outcomes, a multicenter cross sectional Japanese study

We aimed to clarify how maternal physical characteristics explains the association between adolescent pregnancy and adverse birth outcomes, focusing on their height. We used a national multicenter-based delivery registry among 30,831 women under age 25 years with a singleton pregnancy between 2005 and 2011. Adolescent pregnancy was defined as younger than 20 years of age, and categorized into “junior adolescent” (aged ≤15 years) and “senior adolescent” (aged 16–19 years). We used multivariate Poisson regression and mediation analysis to assess the extent to which maternal height explained the association between adolescent pregnancy and risk of adverse birth outcomes. Risks for preterm birth [(adjusted risk ratio (aRR) 1.17, 95% confidence interval (95% CI), 1.08–1.27], low birthweight (aRR 1.08, 95% CI, 1.01–1.15), and low Apgar score (aRR 1.41 95%CI, 1.15–1.73) were significantly higher among adolescent women compared to women of 20–24 years of age. The mediation effect of maternal height on these outcomes were moderate for low birthweight (45.5%) and preterm birth (10.5%), and smaller for low Apgar score (6.6%). In all analyses, we did not detect significant differences between junior adolescent and senior adolescent. Adolescent women have higher risk of adverse birth outcomes. This association is partially mediated by shorter maternal height.

Impact of maternal height and gestational diabetes mellitus on offspring birthweight

AIMS

To evaluate the impact of gestational diabetes mellitus (GDM) and maternal height on offspring birthweight.

METHODS

This is an observational cohort study, encompassing 4 111 Finnish primiparous women from Vantaa city, Finland, with singleton deliveries between 2009 and 2015. Data were obtained from the Finnish Medical Birth Register. The study population was divided into five groups according to maternal height. Cut-offs for height levels were I ≤ 158 cm, II 159-163 cm, III 164-167 cm, IV 168-172 cm, V ≥ 173 cm. The main outcome measure was offspring birthweight, expressed as Z-scores according to sex and gestational age.

RESULTS

Independently, both maternal height and GDM increased offspring birthweight (p < 0.001 for height and GDM). When studying the interaction, a significant increase in offspring birthweight was noted only in extreme height categories; group I ≤ 158 cm (p = 0.011), group IV 168-172 cm (p = 0.010) and group V ≥ 173 cm (p < 0.001) and the impact was similar in both sexes. Maternal height had no impact on offspring ponderal index (p = 0.20 for trend).

CONCLUSIONS

In extreme height categories, short and tall primiparous women with GDM are at risk for delivering larger offspring compared to women without GDM of similar height.

The influence of maternal height on offspring's birth weight in Merida, Mexico

OBJECTIVES

To analyze the influence of maternal height (MH) on offspring's birth weight (BW) in infants born from January 2016 to May 2017, in Merida, Mexico.

METHODS

A total of 3462 singletons born at term in a public hospital were analyzed. Data extracted from hospital records were MH; number of previous births; and infant's sex, BW, and gestational length. MH was divided into 4 categories at quartile points: Q1:129-147, Q2:148-151, Q3:152-155, and Q4:156-180 cm. BW data were transformed to z-score values using the WHO Child Growth Standard. The association between MH and infants' BW was analyzed through a multiple regression model in which gestational length, infant's sex, maternal age, ethnicity, and number of previous birth were included as covariates.

RESULTS

Mean values of MH and infants' BW were 151.43 cm (SD = 6.32) and 3172 g (SD = 401) (corresponding to -0.29 SD in BW z-score), respectively. The regression model showed that the shortest quartile of MH was associated with -0.43 (95% CI -0.35 -0.51) SD in infants' BW compared with the highest quartile. The second and third shortest quartiles of MH were associated with -0.24 (95% CI -0.16 -0.32) and -0.17 (95% CI -0.09 -0.25) SD of infants BW, respectively.

CONCLUSIONS

MH remains an important factor for infant BW even in the presence of other determinants. The influence of MH on infants' BW in this population is similar to that found in other populations in low-, middle-, and high-income countries.

Determinants of low birth weight in the context of maternal nutrition education in urban informal settlements, Kenya

Inadequate knowledge in maternal nutrition is one of the determinants of low birth weight. However, little evidence is available on whether maternal nutrition counselling alone can influence birth weight among women from low socioeconomic households. This study assessed the effect of prenatal maternal nutritional counselling on birth weight and examined the related risk factors. A cluster randomized controlled trial was conducted to assess the effectiveness of home-based maternal nutritional counselling on nutritional outcomes, morbidity, breastfeeding, and infant feeding practices by the African Population and Health Research Center in two urban informal settlements of Nairobi. The intervention group received monthly antenatal and nutritional counselling from trained community health volunteers; meanwhile, the control group received routine antenatal care. A total of 1001 participants were included for analysis. Logistic regression was applied to determine associations between low birth weight and maternal characteristics. A higher prevalence of low birth weight was observed in the control group (6.7%) than in the intervention group (2.5%; P&lt;0.001). Logistic regression identified significant associations between birth weight and intervention group (adjusted odds ratio (AOR)=0.26; 95% confidence interval (CI), 0.10-0.64); maternal height &lt;154.5 cm (AOR=3.33; 95% CI, 1.01-10.96); last antenatal care visits at 1st or 2nd trimesters (AOR=9.48; 95% CI, 3.72-24.15); pre-term delivery (AOR=3.93; 95% CI, 1.93-7.98); maternal mid-upper arm circumference &lt;23 cm (AOR=2.57; 95% CI, 1.15-5.78); and cesarean delivery (AOR=2.27; 95% CI, 1.04-4.94). Nutrition counselling during pregnancy reduced low birth weight and preterm births, which was determined by women of short stature, early stoppage of antenatal visit, and cesarean delivery.

Maternal breast cancer risk in relation to birthweight and gestation of her offspring

BACKGROUND

Parity and age at first pregnancy are well-established risk factors for breast cancer, but the effects of other characteristics of pregnancies are uncertain and the literature is inconsistent.

METHODS

In a cohort of 83,451 parous women from the general population of the UK, which collected detailed information on each pregnancy and a wide range of potential confounders, we investigated the associations of length of gestation and birthweight of offspring in a woman's pregnancies with her breast cancer risk, adjusting for a full range of non-reproductive as well as reproductive risk factors unlike in previous large studies.

RESULTS

Gestation of the first-born offspring was significantly inversely related to the risk of pre-menopausal breast cancer (p trend = 0.03; hazard ratio (HR) for 26-31 compared with 40-41 weeks, the baseline group, = 2.38, 95% confidence interval (CI) 1.26-4.49), and was borderline significantly related to risk of breast cancer overall (p trend = 0.05). Risk was significantly raised in mothers of high birthweight first-born (HR for breast cancer overall = 1.53, 95% CI 1.06-2.21 for ≥ 4500 g compared with 3000-3499 g, the baseline group). For gestation and birthweight of most recent birth, there were no clear effects. Analyses without adjustment for confounders (other than age) gave similar results.

CONCLUSIONS

Our data add to evidence that short gestation pregnancies may increase the risk of breast cancer, at least pre-menopausally, perhaps by hormonal stimulation and breast proliferation early in pregnancy without the opportunity for the differentiation that occurs in late pregnancy. High birthweight first pregnancies may increase breast cancer risk, possibly through the association of birthweight with oestrogen and insulin-like growth factor 1 levels.

Maternal height and risk of caesarean section in singleton births in Sweden-A population-based study using data from the Swedish Pregnancy Register 2011 to 2016

Caesarean section (CS) has short and long term adverse health consequences, and should therefore only be undertaken when necessary. Risk factors such as maternal age, maternal body mass index (BMI) and fetal weight have been extensively investigated in relation to CS, but the significance of maternal height has been less explored in Sweden. The aim was to investigate the significance of maternal height on risk of CS in a representative, population-based sample from Sweden, also taking into account confounders. Data on singleton births in the Swedish Pregnancy Register 2011 to 2016 were collected, including women with heights of 140 cm and above, constituting a sample of 581,844 women. Data were analysed with epidemiological and biostatistical methods. Mean height was 166.1 cm. Women born outside Sweden were significantly shorter than women born in Sweden (162.8 cm vs. 167.1 cm, p<0.001). There was a decreasing risk of CS with increasing maternal height. This effect remained after adjustment for other risk factors for CS such as maternal age, BMI, gestational age, parity, high birth weight and country of birth. Frequency of CS was higher among women born outside Sweden compared with Swedish-born women (17.3% vs. 16.0%), however, in a multiple regression model country of birth outside Sweden diminished as a risk factor for CS. Maternal height of 178-179 cm was associated with the lowest risk of CS (OR = 0.76, CI95% 0.71-0.81), whereas height below 160 cm explained 7% of CS cases. BMI and maternal age are established factors involved in clinical assessments related to birth, and maternal height should increasingly enjoy a similar status in these considerations. Moreover, when healthcare professionals are counselling pregnant women, taller stature should be more emphasized as a positive indicator for successful vaginal birth to increase pregnant women's confidence in giving birth vaginally, with possible positive impacts for lowering CS rates.

Effect of maternal origin on the association between maternal height and risk of preterm birth in Belgium: a retrospective observational cohort study

OBJECTIVES

To investigate the effect of maternal origin on the association between maternal height and the risk of preterm birth (PTB).

DESIGN

Retrospective observational cohort study.

SETTING

Two of the three Belgian regions, including Brussels-Capital and Walloon regions.

PARTICIPANTS

A total of 245 204 women spontaneously delivered live singletons between 2009 and 2013. Maternal nationality at the time of birth included Belgium, Congo, French, Italy, Morocco, Poland, Romania and Turkey.

OUTCOMES MEASURES

The outcome variable was spontaneous PTB, defined as childbirth occurring at less than 37 weeks' gestation.

RESULTS

Average height, demographic characteristics and the spontaneous PTB rate differed according to maternal origin, defined as maternal nationality at birth. The pattern of association between maternal height and the risk of PTB was not uniform by maternal nationality at birth. The low maternal height category was associated with a statistically significant increased risk of spontaneous PTB for Belgian (adjusted OR (aOR) 1.23, 95% CI 1.16 to 1.32), Italian (aOR 1.48, 95% CI 1.12 to 1.96) and Polish (aOR 1.76, 95% CI 1.11 to 2.78), respectively. However, this association was not observed for the women from Congo, France, Morocco, Romania and Turkey.

CONCLUSIONS

The association between height and the risk of PTB was modified by maternal nationality, even for mothers from the same region of the world. For example, there was a significant inverse association for the Belgians and Italians but not for French women. Our data suggest that PTB risk assessment should take into account the specific height of maternal origin.

The Relationships of Health Behaviour and Psychological Characteristics with Spontaneous Preterm Birth in Nulliparous Women

Objectives Preterm birth is the leading pregnancy outcome associated with perinatal morbidity and mortality and remains difficult to prevent. There is evidence that some modifiable maternal health characteristics may influence the risk of preterm birth. Our aim was to investigate the relationships of self-reported maternal health behaviour and psychological characteristics in nulliparous women with spontaneous preterm birth in prenatal primary care. Methods The data of our prospective study was obtained from the nationwide DELIVER multicentre cohort study (September 2009–March 2011), which was designed to examine perinatal primary care in the Netherlands. In our study, consisting of 2768 nulliparous women, we estimated the relationships of various self-reported health behaviours (smoking, alcohol consumption, folic acid supplementation, daily fruit, daily fresh vegetables, daily hot meal and daily breakfast consumption) and psychological characteristics (anxious/depressed mood and health control beliefs) with spontaneous preterm birth as a dichotomous outcome. Due to the clustering of clients within midwife practices, Generalized Estimating Equations was used for these analyses. Results Low health control beliefs was the sole characteristic significantly associated with spontaneous preterm birth (odds ratio 2.26; 95 % confidence interval 1.51, 3.39) after being adjusted for socio-demographics, anthropometrics and the remaining health behaviour and psychological characteristics. The other characteristics were not significantly associated with spontaneous preterm birth. Conclusions for Practice Maternal low health control beliefs need to be explored further as a possible marker for women at risk for preterm birth, and as a potentially modifiable characteristic to be used in interventions which are designed to reduce the risk of spontaneous preterm birth.

Are risk factors for preterm and early-term live singleton birth the same? A population-based study in France

OBJECTIVES

To investigate whether risk factors for preterm (<37 weeks gestation) and early-term birth (37 and 38 weeks gestation) are similar.

DESIGN

Nationally representative cross-sectional study of births.

SETTING

France in 2010.

PARTICIPANTS

Live singleton births (n=14 326).

PRIMARY AND SECONDARY OUTCOME MEASURES

Preterm and early-term birth rates overall and by mode of delivery (spontaneous and indicated). Risk factors were maternal sociodemographic characteristics, previous preterm birth, height, prepregnancy body mass index (BMI) and smoking, assessed using multinomial regression models with full-term births 39 weeks and over as the reference group.

RESULTS

There were 5.5% preterm and 22.5% early-term births. Common risk factors were: a previous preterm delivery (adjusted relative risk ratio (aRRR) 8.2 (95% CI 6.2 to 10.7) and aRRR 2.4 (95% CI 2.0 to 3.0), respectively), short stature, underweight (overall and in spontaneous deliveries), obesity (in indicated deliveries only), a low educational level and Sub-Saharan African origin. In contrast, primiparity was a risk factor only for preterm birth, aRRR 1.8 (95% CI 1.5 to 2.2), while higher parity was associated with greater risk of early-term birth.

CONCLUSIONS

Most population-level risk factors were common to both preterm and early-term birth with the exception of primiparity, and BMI which differed by mode of onset of delivery. Our results suggest that preterm and early-term birth share similar aetiologies and thus potentially common strategies for prevention.

Influence of gestational weight gain on low birth weight in short-statured South Indian pregnant women

BACKGROUND/OBJECTIVES

India contributes to one-third of the global burden of low birth weight (LBW) neonates, which is associated with increased risk of mortality and adverse consequences on long-term health. Factors leading to LBW are multidimensional and maternal short stature is an important component with an inter-generational effect. On the contrary gestational weight gain (GWG) shows an independent positive influence on birth weight. The aim of the present study therefore was to determine the influence of GWG on birth weight in short pregnant women.

SUBJECTS/METHODS

A prospective observational cohort of 1254 pregnant women was studied. Total, second and third trimester GWG per week were computed. Women were divided into two groups, "short" and "not-short", using a cut off of 152 cm that corresponded to the 25th percentile for height in the cohort. Association of tertiles of GWG with LBW was examined using log binomial regression analysis.

RESULTS

"Short" women in highest tertile of total GWG had a significantly reduced adjusted relative risk (ARR 0.37, 95% confidence interval 0.16-0.83, P = 0.016) for LBW, compared to the lowest tertile. However, there was no significant increase in risk for cesarean section (CS) with increasing tertiles of total GWG.

CONCLUSIONS

In women with height <152 cm a significant reduced risk for LBW was observed with the greatest total GWG, without a significant increase in the risk for CS. This suggests that improving GWG in short women may be beneficial for the birth weight of the offspring.

Maternal experience of intimate partner violence and low birth weight of children: A hospital-based study in Bangladesh

OBJECTIVE

Intimate partner violence (IPV) is the most prevalent form of gender-based violence worldwide. IPV either before or during pregnancy has been documented as a risk factor for the health of the mother and her unborn child. The aim of this study was to examine the relationship between maternal experience of IPV and low birth weight (LBW).

STUDY DESIGN

A hospital-based survey was conducted among women in the postnatal wards of a large public hospital at Rajshahi, Bangladesh. Data on socio-economic characteristics, reproductive health characteristics, intimate partner violence, and antenatal, delivery and newborn care were collected from 400 women between July 2015 and April 2016.

RESULTS

Results of this study indicated that 43% of women reported experiencing any physical IPV in their lifetime, 35.5% of them experienced sexual IPV, and 32.5% experienced both physical and sexual IPV. Approximately one in every three (29.2%) infants was born with LBW. Physical IPV was associated with an increased risk of having a child with low birth weight (adjusted odds ratio [AOR]: 3.01, 95% CI: 2.35-5.81). The risk of infants born with LBW increased with women's lifetime experience of sexual IPV (AOR: 1.98; 95% CI: 1.23-4.15) and both physical and sexual IPV (AOR: 4.05; 95% CI: 2.79-7.33).

CONCLUSION

Maternal lifetime experience of IPV is positively associated with LBW children. Preventing women from the experience of IPV may help improve neonatal and child mortality in Bangladesh.

Maternal body mass index and the prevalence of spontaneous and elective preterm deliveries in an Irish obstetric population: a retrospective cohort study

OBJECTIVE

To estimate the association between maternal body mass index (BMI) and risk of spontaneous preterm delivery (sPTD) and elective preterm delivery (ePTD) in singleton and multiple pregnancies.

DESIGN

Retrospective cohort study.

SETTING

Electronic records of all deliveries from 2009 through 2013 in a tertiary university hospital were abstracted for demographic and obstetrical information.

PARTICIPANTS

A total of 38 528 deliveries were included. Participants with missing data were excluded from the study. BMI was calculated from the measurement of height and weight at the first prenatal visit and categorised. Sonographic confirmation of gestational age was standard.

OUTCOME MEASURES

Primary outcomes, sPTD and ePTD in singleton and multiple pregnancies, were evaluated by multinomial logistic regression analyses, stratified by parity, controlling for confounding variables.

RESULTS

Overall rate of PTD was 5.9%, from which 2.7% were sPTD and 3.2% ePTD. The rate of PTD was 50.4% in multiple pregnancies and 5.0% in singleton pregnancies. The risk of sPTD was increased in obese nulliparas (adjusted OR (aOR) 2.8, 95% CI 1.7 to 4.4) and underweight multiparas (aOR 2.2, 95% CI 1.3 to 3.8). The risk of ePTD was increased in underweight nulliparas (aOR 1.8; 95% CI 1.04 to 3.4) and severely obese multiparas (aOR 1.4, 95% CI 1.02 to 3.8).Severe obesity increased the risk of both sPTD (aOR 1.4; 95% CI 1.01 to 2.1) and ePTD (aOR 1.4; 95% CI 1.1 to 1.8) in singleton pregnancies. Obesity did not influence the rate of either sPTD or ePTD in multiple pregnancies.

CONCLUSION

Maternal obesity is an independent risk factor for PTD in singleton pregnancies but not in multiple pregnancies. Obesity and nulliparity increase the risk of sPTD, whereas obesity and multiparity increase the risk of ePTD.

Childhood stunting in relation to the pre- and postnatal environment during the first 2 years of life: The MAL-ED longitudinal birth cohort study

BACKGROUND

Stunting is the most prevalent manifestation of childhood malnutrition. To characterize factors that contribute to stunting in resource-poor settings, we studied a priori selected biological and social factors collected longitudinally in a cohort of newborns.

METHODS AND FINDINGS

We enrolled 1,868 children across 7 resource-poor settings in Bangladesh, Brazil, India, Nepal, Peru, South Africa, and Tanzania shortly after birth and followed them for 24 months between 2 November 2009 and 28 February 2014. We collected longitudinal anthropometry, sociodemographic factors, maternal-reported illnesses, and antibiotic use; child feeding practices; dietary intake starting at 9 months; and longitudinal blood, urine, and stool samples to investigate non-diarrheal enteropathogens, micronutrients, gut inflammation and permeability, and systemic inflammation. We categorized length-for-age Z-scores into 3 groups (not stunted, ≥-1; at risk, <-1 to -2; and stunted, <-2), and used multivariable ordinal logistic regression to model the cumulative odds of being in a lower length-for-age category (at risk or stunted). A total of 1,197 children with complete longitudinal data were available for analysis. The prevalence of having a length-for-age Z-score below -1 increased from 43% (range 37%-47% across sites) shortly after birth (mean 7.7 days post-delivery, range 0 to 17 days) to 74% (16%-96%) at 24 months. The prevalence of stunting increased 3-fold during this same time period. Factors that contributed to the odds of being in a lower length-for-age category at 24 months were lower enrollment weight-for-age (interquartile cumulative odds ratio = 1.82, 95% CI 1.49-2.23), shorter maternal height (2.38, 1.89-3.01), higher number of enteropathogens in non-diarrheal stools (1.36, 1.07-1.73), lower socioeconomic status (1.75, 1.20-2.55), and lower percent of energy from protein (1.39, 1.13-1.72). Site-specific analyses suggest that reported associations were similar across settings. While loss to follow-up and missing data are inevitable, some study sites had greater loss to follow-up and more missing data than others, which may limit the generalizability of the findings.

CONCLUSIONS

Neonatal and maternal factors were early determinants of lower length-for-age, and their contribution remained important throughout the first 24 months of life, whereas the average number of enteropathogens in non-diarrheal stools, socioeconomic status, and dietary intake became increasingly important contributors by 24 months relative to neonatal and maternal factors.