Differences in risk factors for incident and recurrent small-for-gestational-age birthweight: a hospital-based cohort study

Can the neutrophil-to-lymphocyte ratio be used as an early marker of small fetuses for gestational age? A prospective study

Background

Small-for-gestational-age (SGA) fetuses are at increased risk of mortality and morbidity, and less than 30% will be detected by any ultrasound scan within 4 weeks before delivery. Our aim was to evaluate the relationship between neutrophil/lymphocyte ratio (NLR) in the first trimester of pregnancy and SGA fetuses.

Method

We performed a prospective study between June 2021 and August 2022, to evaluate the relationship between the neutrophil to lymphocyte ratio in maternal blood in the first trimester of pregnancy, with the birth of an SGA fetus. One hundred ninety-four participants with singleton pregnancies between 11 + 1 and 13 + 6 weeks of gestation were recruited. Pregnancies affected with diagnosed fetal chromosomal abnormalities, or chronic pathologies were excluded. SGA was defined as birthweight less than the 10th centile (N = 42) and severe SGA as birthweight less than the 3rd centile for gestation (N = 10) according to a locally derived descriptive charts. The NLR value measured in the first trimester was compared between these two groups and controls.

Results

We found no statistically significant difference in NLR, (3.5 +/-1.2 vs. 3.4+/-1.2, p-value of 0.78) when comparing the SGA less than the 10th centile group to the control group. NLR was also not different between severe SGA and controls (3.6+/-1.4 vs. 3.4+/-1.2 p-value of 0.78).

Conclusion

We found no association between first-trimester NLR ratio and SGA.

Racial and ethnic differences in the risk of recurrent preterm or small for gestational age births in the United States: a systematic review and stratified analysis

BACKGROUND

The risk of recurrent adverse birth outcomes has been reported worldwide, but there are limited estimates of these risks by social subgroups such as race and ethnicity in the United States. We assessed racial and ethnic disparities in the risk of recurrent adverse birth outcomes, including preterm birth, low birthweight, fetal growth restriction, small for gestational age, stillbirth, and neonatal mortality in the U.S.

METHODS

We searched MEDLINE, CINAHL Complete, Web of Science, and Scopus from the date of inception to April 5, 2022. We identified 3,540 articles for a title and abstract review, of which 80 were selected for full-text review. Studies were included if they focused on the recurrence of any of the six outcomes listed in the objectives. Study quality was assessed using the NIH Study Quality Assessment Tool. Heterogeneity across studies was too large for meta-analysis, but race and ethnicity-stratified estimates and tests for homogeneity results were reported.

RESULTS

Six studies on recurrent preterm birth and small for gestational age were included. Pooled comparisons showed a higher risk of recurrent preterm birth and small for gestational age for all women. Stratified race comparisons showed a higher but heterogeneous risk of recurrence of preterm birth across Black and White women. Relative risks of recurrent preterm birth ranged from 2.02 [1.94, 2.11] to 2.86 [2.40, 3.39] for Black women and from 3.23 [3.07, 3.39] to 3.92 [3.35, 4.59] for White women. The evidence was weak for race and ethnicity stratification for Hispanic and Asian women for both outcomes.

CONCLUSIONS

Disparities exist in the recurrence of preterm birth, and race/ethnicity-concordant comparisons suggest race is an effect modifier for recurrent preterm birth for Black and White women. Due to the small number of studies, no conclusions could be made for small for gestational age or Hispanic and Asian groups. The results pose new research areas to better understand race-based differences in recurrent adverse birth outcomes.

Birth spacing and risk of adverse pregnancy and birth outcomes: A systematic review and dose-response meta-analysis

INTRODUCTION

The association between extreme birth spacing and adverse outcomes is controversial, and available evidence is fragmented into different classifications of birth spacing.

MATERIAL AND METHODS

We conducted a systematic review of observational studies to evaluate the association between birth spacing (i.e., interpregnancy interval and interoutcome interval) and adverse outcomes (i.e., pregnancy complications, adverse birth outcomes). Pooled odds ratios (ORs) with 95% confidence intervals (CI) were calculated using a random-effects model, and the dose-response relationships were evaluated using generalized least squares trend estimation.

RESULTS

A total of 129 studies involving 46 874 843 pregnancies were included. In the general population, compared with an interpregnancy interval of 18-23 months, extreme intervals (<6 months and ≥ 60 months) were associated with an increased risk of adverse outcomes, including preterm birth, small for gestational age, low birthweight, fetal death, birth defects, early neonatal death, and premature rupture of fetal membranes (pooled OR range: 1.08-1.56; p < 0.05). The dose-response analyses further confirmed these J-shaped relationships (pnon-linear  < 0.001-0.009). Long interpregnancy interval was only associated with an increased risk of preeclampsia and gestational diabetes (pnon-linear  < 0.005 and pnon-linear  < 0.001, respectively). Similar associations were observed between interoutcome interval and risk of low birthweight and preterm birth (pnon-linear  < 0.001). Moreover, interoutcome interval of ≥60 months was associated with an increased risk of cesarean delivery (pooled OR 1.72, 95% CI 1.04-2.83). For pregnancies following preterm births, an interpregnancy interval of 9 months was not associated with an increased risk of preterm birth, according to dose-response analyses (pnon-linear  = 0.008). Based on limited evidence, we did not observe significant associations between interpregnancy interval or interoutcome interval after pregnancy losses and risk of small for gestational age, fetal death, miscarriage, or preeclampsia (pooled OR range: 0.76-1.21; p > 0.05).

CONCLUSIONS

Extreme birth spacing has extensive adverse effects on maternal and infant health. In the general population, interpregnancy interval of 18-23 months may be associated with potential benefits for both mothers and infants. For women with previous preterm birth, the optimal birth spacing may be 9 months.

Assessment of Nutritional Status in the Diagnostic Evaluation of the Child with Growth Failure

Current clinical guidelines provide information about the diagnostic workup of children with growth failure. This mini-review focuses on the nutritional assessment, which has received relatively little attention in such guidelines. The past medical history, in particular a low birth size and early feeding problems, can provide information that can increase the likelihood of nutritional deficits or several genetic causes. The current medical history should include a dietary history and can thereby reveal a poorly planned or severely restricted diet, which can be associated with nutritional deficiencies. Children on a vegan diet should receive various nutritional supplements, but insufficient compliance has been reported in one-third of cases. While proper use of nutritional supplements in children consuming a vegan diet appears to be associated with normal growth and development, insufficient intake of supplements may impede growth and bone formation. Physical examination and analysis of height and weight over time can help differentiating between endocrine causes, gastrointestinal disorders, psychosocial problems, or underlying genetic conditions that prevent adequate nutritional intake. Laboratory screening should be part of the workup in every child with short stature, and further laboratory tests can be indicated if warranted by the dietary history, especially in children on a poorly planned vegan diet.

Maternal socioeconomic and lifestyle factors and life dissatisfaction associated with a small for gestational age infant. The Survey of Neonates in Pomerania (SNiP)

PURPOSE

The aim is to investigate the associations of the mother's socioeconomic and lifestyle factors and life satisfaction with the delivery of a small for gestational age (SGA) infant.

METHODS

Data from 4598 participants of the population-based birth cohort study Survey of Neonates in Pomerania (SniP) including comprehensive information on pregnancies, mothers, and their offspring in Western Pomerania, Germany were used in this study. The associations were analyzed using linear and logistic regression models.

RESULTS

After logistic regression analysis adjusted for height of the mother, women who delivered SGA infants, had lower education (p < 0.01) and smoked more frequently during pregnancy (p < 0.01) compared with mothers of adequate for gestational age (AGA) neonates. A mother with less than 10 years of education and one who continued smoking during pregnancy had an odds ratio (OR) of 2.23 [95% confidence interval (CI) = 1.44 to 3.46] and 2.68 (95% CI = 2.06-3.49) of having an SGA infant, respectively. There was no association between the employment of the mother (p = 0.28), the monthly income (p = 0.09), the family status (p = 0.80), the number of friendships outside the household that the mother would not wish to relinquish (p = 0.47), the number of people that she could rely on in case of an emergency (p = 0.75), or alcohol consumption prior to (p = 0.14) or during the pregnancy (p = 0.99) with SGA. Finally, women who delivered SGA infants were more frequently dissatisfied with their employment (p = 0.03) and financial status (p < 0.01).

CONCLUSIONS

Women who delivered SGA infants had more associated socioeconomic and lifestyle risk factors and were more frequently dissatisfied with their life conditions than mothers of AGA neonates.

Significant risk of repeat adverse outcomes in recurrent gestational diabetes pregnancy: a retrospective cohort study

BACKGROUND

The risk of adverse outcomes in recurrent GDM pregnancy has not been well documented, particularly in women who have already had an adverse outcome. The aim of this study was to compare the risk of recurrent adverse delivery outcome (ADO) or adverse neonatal outcome (ANO) between consecutive gestational diabetes (GDM) pregnancies.

METHODS

In this retrospective study of 424 pairs of consecutive ("index" and "subsequent") GDM pregnancies, we compared the risk of ADO (instrumental delivery, emergency Caesarean section) and ANO (large for gestational age (LGA and small for gestational age (SGA)) in women with and without a history of adverse outcome in their index pregnancy.

RESULTS

Subsequent pregnancies had higher rates of elective Caesarean (30.4% vs 17.0%, p < 0.001) and lower rates of instrumental delivery (5% vs 13.9%, p < 0.001), emergency Caesarean (7.1% vs 16.3%, p < 0.001) and vaginal delivery (62.3% vs 66.3%, p = 0.01). Index pregnancy adverse outcome was associated with a higher risk of repeat outcome: RR 3.09 (95%CI:1.30,7.34) for instrumental delivery, RR 2.20 (95%CI:1.06,4.61) for emergency Caesarean, RR 4.55 (95%CI:3.03,6.82) for LGA, and RR 5.01 (95%CI:2.73,9.22) for SGA). The greatest risk factor for subsequent LGA (RR 3.13 (95%CI:2.20,4.47)) or SGA (RR 4.71 (95%CI:2.66,8.36)) was having that outcome in the index pregnancy.

CONCLUSION

A history of an adverse outcome is a powerful predictor of the same outcome in the subsequent GDM pregnancy. These high-risk women may warrant more directed management over routine GDM care such as altered glucose targets or increased frequency of ultrasound assessment.

International Consensus Guideline on Small for Gestational Age (SGA): Etiology and Management from Infancy to Early Adulthood

This International Consensus Guideline was developed by experts in the field of SGA of 10 pediatric endocrine societies worldwide. A consensus meeting was held and 1300 articles formed the basis for discussions. All experts voted about the strengths of the recommendations. The guideline gives new and clinically relevant insights into the etiology of short stature after SGA birth, including novel knowledge about (epi)genetic causes. Besides, it presents long-term consequences of SGA birth and new treatment options, including treatment with gonadotropin-releasing hormone agonist (GnRHa) in addition to growth hormone (GH) treatment, and the metabolic and cardiovascular health of young adults born SGA after cessation of childhood-GH-treatment in comparison with appropriate control groups. To diagnose SGA, accurate anthropometry and use of national growth charts are recommended. Follow-up in early life is warranted and neurodevelopment evaluation in those at risk. Excessive postnatal weight gain should be avoided, as this is associated with an unfavorable cardio-metabolic health profile in adulthood. Children born SGA with persistent short stature < -2.5 SDS at age 2 years or < -2 SDS at age of 3-4 years, should be referred for diagnostic work-up. In case of dysmorphic features, major malformations, microcephaly, developmental delay, intellectual disability and/or signs of skeletal dysplasia, genetic testing should be considered. Treatment with 0.033-0.067 mg GH/kg/day is recommended in case of persistent short stature at age of 3-4 years. Adding GnRHa treatment could be considered when short adult height is expected at pubertal onset. All young adults born SGA require counseling to adopt a healthy lifestyle.

The impact of HPV vaccination beyond cancer prevention: effect on pregnancy outcomes

While the benefits of human papillomavirus (HPV) vaccination relating to cervical cancer prevention have been widely documented, recent published evidence is suggestive of an impact on adverse pregnancy outcomes (APOs) in vaccinated mothers and their infants, including a reduction in rates of preterm births and small for gestational age infants. In this review, we examine this evidence and the possible mechanisms by which HPV vaccination may prevent these APOs. Large-scale studies linking HPV vaccination status with birth registries are needed to confirm these results. Potential confounding factors to consider in future analyses include other risk factors for APOs, and historical changes in both the management of cervical precancerous lesions and prevention of APOs. If confirmed, these additional benefits of HPV vaccination in reducing APO rates will be of global significance, due to the substantial health, social and economic costs associated with APOs, strengthening the case for worldwide HPV immunization.

The risk of recurrent small-for-gestational-age infants at term is dependent on the number of previously affected births

BACKGROUND

Small-for-gestational-age infants are at a substantially increased risk of perinatal complications, but the risk of recurrent small-for-gestational-age is not well known, particularly because there are many demographic and obstetrical factors that interact and modify this risk. We investigated the relationship between previous small-for-gestational-age births and the risk of recurrence at term in a large Australian cohort.

OBJECTIVE

We aimed to identify key demographic and obstetrical variables that influence the risk of recurrence of a small-for-gestational-age infant at term. The primary outcome measure was the odds of recurrence of small-for-gestational-age in subsequent pregnancies up to a maximum of 4 consecutive term births.

STUDY DESIGN

This was a retrospective analysis of women who had more than 1 consecutive nonanomalous, singleton, term live births between July 1997 and September 2018 at the Mater Mother's Hospital in Brisbane, Australia. Women with multiple pregnancy, preterm birth, or major congenital malformations were excluded. Small-for-gestational-age was defined as birthweight at the <10th centile. We calculated the odds of recurrence depending on the number of previous small-for-gestational-age infants and if only the preceding infant was small-for-gestational-age. The study population was dichotomized into small-for-gestational-age and non-small-for-gestational-age for each consecutive pregnancy. Univariate analyses compared baseline demographic and obstetrical characteristics followed by logistic regression modeling to determine the odds of recurrence in the second, third, and fourth pregnancies.

RESULTS

The final study comprised 24,819 women. The proportion of women who had a small-for-gestational-age infant in their first pregnancy was 9.4%, whereas the proportion of women who had a small-for-gestational-age infant in their second, third, and fourth pregnancies after the birth of a previous small-for-gestational-age infant were 20.5% (479 of 2338), 24.6% (63 of 256), and 30.4% (14 of 46), respectively. Regardless of parity, the odds of recurrence increased if the preceding infant was small-for-gestational-age. The odds of recurrence increased markedly if there was more than 1 previous small-for-gestational-age infant. In women with 3 previous small-for-gestational-age infants, the adjusted odds of another small-for-gestational-age infant were 66.00 (95% confidence interval, 11.35-383.76). Maternal age, body mass index, ethnicity, and smoking were significant risk factors for recurrent small-for-gestational-age. However, maternal diabetes mellitus or hypertension, either in a previous or current pregnancy, did not influence the risk of recurrence.

CONCLUSION

The risk of recurrence in a subsequent pregnancy increased if there was a previous small-for-gestational-age birth. Women with consecutive small-for-gestational-age infants were at the highest risk of recurrence. Our results highlight that women with a previous small-for-gestational-age infant are at a substantial risk of another small infant and need to be counseled and monitored appropriately.

Recurrence Risk of Fetal Growth Restriction: Management of Subsequent Pregnancies

Fetal growth restriction (FGR) is a common obstetric complication that predisposes to mortality across the lifespan. Women with a prior pregnancy affected by FGR have a 20% to 30% risk of recurrence, but effective preventive strategies are lacking. Pharmacologic interventions to prevent FGR are lacking. Low-dose aspirin may be somewhat effective, but low-molecular-weight heparin and sildenafil are not. Surveillance in a subsequent pregnancy may consist of serial ultrasonography with timing and frequency determined by the clinical severity in the index pregnancy. Once FGR is diagnosed, the principal management strategy consists of close surveillance and carefully timed delivery.

Trends of change in the individual contribution of risk factors for small for gestational age over more than 2 decades

PURPOSE

Over the past years, the prevalence of various risk factors for small for gestational age (SGA) neonates has changed. Little is known if there was also a change in the specific contribution of these risk factors to the prevalence of SGA. We aim to identify trends in the specific contribution of various risk factors for SGA by observing their odds ratios (ORs) throughout different time periods.

METHODS

A nested case-control study was conducted. The ORs for selected known risk factors for SGA occurring in three consecutive 8-year intervals between 1988 and 2014 (T1 - 1988-1996; T2 - 1997-2005; T3 - 2006-2014) were compared. Data were retrieved from the medical centre's computerized perinatal database. Multivariable logistic regression models were constructed and ORs were compared to identify the specific contribution of independent risk factors for SGA along the study period.

RESULTS

During the study period, 285,992 pregnancies met the study's inclusion criteria, of which 15,013 (5.25%) were SGA. Between 1988 and 2014, the incidence of SGA increased from 2.6% in 1988 to 2.9% in 2014. Using logistic regression models, nulliparity, maternal age, gestational age, hypertensive disorders of pregnancy, oligohydramnios and pre-gestational diabetes mellitus were found to be independently associated with SGA. While the adjusted ORs (aOR) of hypertensive disorders of pregnancy and pre-gestational diabetes mellitus had increased, aORs for nulliparity, maternal age and gestational age had remained stable over time. Oligohydramnios had demonstrated a mixed trend of change over the time.

CONCLUSION

In our study, the specific contribution of factors associated with SGA had changed over time. Having a better understating of the changes in the specific contribution of different risk factors for SGA may enable obstetricians to provide consultations.

Effect of maternal active smoking during pregnancy on the trajectory of childhood body mass index: A multilevel analysis using quartiles of birthweight

INTRODUCTION

Maternal active smoking during pregnancy is associated with childhood obesity; however, whether maternal active smoking affects childhood body mass index (BMI) according to birthweight has not been examined.

METHODS

The study participants were 1955 women and their single-born infants, born between 1 April 1991 and 31 March 2003, in Koshu City, Japan, for whom complete data for birthweight, pre-pregnancy maternal BMI and pregnancy smoking status were available. Maternal smoking status during pregnancy was recorded using a questionnaire at the time of pregnancy registration. Childhood BMI was estimated by the BMI z-score, established by the World Health Organisation. Birthweight quartiles were grouped by sex and parity (first vs second or higher). Multilevel analysis, including both the individual and time as different level variables by each birthweight quartile, was used to describe the trajectories of BMI z-scores for statistical analyses.

RESULTS

In every quartile group, although children born to smoking mothers were leaner at birth, their BMI z-score increased around the age of 3 years. These children were larger than children born to non-smoking mothers. Significant interactions between maternal active smoking during pregnancy and child’s age were seen in those in the first and second quartiles of birthweight. Moreover, rapid growth in infancy was observed in the second quartile of birthweight.

CONCLUSIONS

The effect of maternal active smoking during pregnancy on childhood growth was more apparent among children in the second quartile of birthweight.

Association between infertility treatment and intrauterine growth: a multilevel analysis in a retrospective cohort study

OBJECTIVES

This study aimed to identify intrauterine growth differences according to infertility treatment compared with spontaneous conception and to describe intrauterine growth trajectories.

DESIGN

Retrospective cohort study.

SETTING

A single primary and tertiary medical centre in Japan.

PARTICIPANTS

This study included singleton pregnant women with prenatal check-ups and delivery at the University of Yamanashi Hospital between 1 July 2012 and 30 September 2017. Patients were divided into four groups: spontaneous conception, infertility treatment without assisted reproductive technology (ART), fresh-embryo transfer and frozen embryo transfer (FET).

INTERVENTIONS

Differences in intrauterine growth according to the infertility treatment, including ART, and birth weight were evaluated. Multilevel analysis was employed to evaluate intrauterine growth trajectories stratified by the sex of the offspring.

PRIMARY OUTCOME MEASURE

Estimated fetal weight (EFW) assessed by ultrasound examination.

RESULTS

We assessed data from 37 239 prenatal examination results from 2377 pregnant women (spontaneous conception, n=1764; infertility treatment without ART, n=171; fresh-embryo transfer, n=112; and FET, n=330) in the final analysis. Multilevel analysis was adjusted for gestation duration, gestation period, parity, hypertensive disorders of pregnancy, type of infertility treatment, maternal age, smoking status, placenta previa, thyroid disease, gestational diabetes mellitus and the interaction between each potential confounding factor and gestation duration. In male fetuses, the interaction between FET and gestational duration (estimate: 0.36; 95% CI: 0.06 to 0.67) significantly affected the EFW. Similarly, in female fetuses, FET (estimate: -69.85; 95% CI: -112.09 to -27.61) and the interaction between FET and gestation duration (estimate: 0.57; 95% CI: 0.28 to 0.87) significantly affected the EFW.

CONCLUSIONS

This study shows that FET affects intrauterine growth trajectory from the second trimester to term, particularly in female fetuses. Our findings require further prospective research to examine the effect of infertility treatment on fetal growth.

Placental pathology in pregnancies complicated by fetal growth restriction: recurrence vs. new onset

OBJECTIVE

In an attempt to shed new light on the pathogenesis of fetal growth restriction (FGR), we aimed to study pregnancy characteristics, neonatal outcomes, and placental histopathological lesions of FGR pregnancies in two different subgroups: when developed after appropriate for gestational age (AGA) pregnancy and when developed after previous pregnancy with FGR.

STUDY DESIGN

Pregnancy and placental reports of all singleton pregnancies complicated by FGR (defined as actual birthweight below the 10th percentile according to local birthweight nomograms) between 2008 and 2018 were reviewed. Included were only cases with previous delivery. Maternal background, neonatal outcomes, and placental histopathology were compared between FGR that occurred after FGR (recurrent FGR group) and FGR that occurred after an AGA pregnancy (FGR after AGA group). Placental lesions were classified according to the current "Amsterdam" criteria. Continuous variables were compared using the Student's t test or the Mann-Whitney test as appropriate. Categorical variables were compared using Chi-square or Fisher's exact test as appropriate.

RESULTS

A total of 334 FGR cases with a previous delivery were included in the study. Of them, 111 cases constituted the recurrent FGR group and 223 constituted the FGR after AGA group. The recurrent FGR group was characterized by higher rates of maternal diabetes during pregnancy and hypertensive diseases (9% versus 2.7%, p = 0.01 and 19.8% versus 11.6%, p = 0.04). The FGR after AGA group was characterized by a higher rate of fetal vascular malperfusion (FVM) lesions (29.6% versus 18.0%, p = 0.02), and by lower mean birthweight (1842 ± 424.9 versus 1977.4 ± 412.2, p = 0.005), as compared to the recurrent FGR group.

CONCLUSION

Recurrent FGR was associated with maternal background morbidities during pregnancy which represents a chronic repeated insult, while "new" FGR cases (those followed an AGA pregnancy) were characterized by a higher rate of FVM lesions and lower birthweight which probably represent an "accident" in placentation. These findings may suggest that different mechanisms of placental dysfunction exist in the two subgroups of FGR.

Association between advanced maternal age and maternal and neonatal morbidity: A cross-sectional study on a Spanish population

Background and objective

Over recent decades, a progressive increase in the maternal age at childbirth has been observed in developed countries, posing a health risk for both women and infants. The aim of this study was to analyze the association between advanced maternal age (AMA) and maternal and neonatal morbidity.

Material and methods

A cross-sectional study of 3,315 births was conducted in the north of Spain in 2014. We compared childbirth between women aged 35 years or older, with a reference group of women aged between 24 and 27 years. AMA was categorized based on ordinal ranking into 35–38 years, 39–42 years, and >42 years to estimate a dose-response pattern (the older the age, the greater the risk). As an association measure, crude and adjusted Odds Ratios (OR) were estimated by non-conditional logistic regression and 95% Confidence Intervals (95%CI) were calculated.

Results

Repeated abortions were more common among women of AMA in comparison to pregnant women aged 24–27 years (reference group): adjusted OR = 2.68; 95%CI (1.52–4.73). A higher prevalence of gestational diabetes was also observed among women of AMA, reaching statistical significance when restricted to first time mothers: adjusted OR = 8.55; 95%CI (1.12–65.43). In addition, the possibility of an instrumental delivery was multiplied by 1.6 and the possibility of a cesarean by 1.5 among women of AMA, with these results reaching statistical significance, and observing a dose-response pattern. Lastly, there were associations between preeclampsia, preterm birth (<37 weeks) and low birthweight, however without reaching statistical significance.

Conclusion

Our results support the association between AMA and suffering repeated abortions. Likewise, being of AMA was associated with a greater risk of suffering from gestational diabetes, especially among primiparous women, as well as being associated with both instrumental deliveries and cesareans among both primiparous and multiparous women.

The mnemonic code of pregnancy: Comparative analyses of pregnancy success and complication risk in first and second human pregnancies

Obstetrical complications such as spontaneous abortion/miscarriage, fetal growth restriction, preeclampsia or preterm birth occur in approx. 15% of human pregnancies. Clinical experts often state that a previous uncomplicated pregnancy reduces the risk for complications in subsequent pregnancies. Vice versa, a prior pregnancy affected by obstetrical complications increases the risk for reoccurrence. However, published evidence directly underpinning these clinical statements is sparse. Considering that the maternal immune adaptation may be causally involved in determining the outcome of subsequent pregnancies, a comprehensive analysis of clinical data was long overdue. We here present a systematic analysis of clinical data using a PubMed-based approach to identify human studies with relevant information on birth weight and incidences of pregnancy complications in first and second pregnancies. From initially 18,592 publications, 37 studies were included in the quantitative data analysis. Women with a previous pregnancy affected by complications where a derailed immune response can be inferred have a 2.2-3.2-fold increased risk to be affected again in a subsequent pregnancy. Conversely, a normally progressing primary pregnancy reduced the risk for complications in a subsequent pregnancy by 35-65%. Moreover, an uncomplicated primary pregnancy was associated with a 4.2% increased birth weight in a following pregnancy without a difference in gestational age at delivery. In conclusion, the increased birth weight after previously uncomplicated pregnancies suggests that an immune memory is mounted during primary pregnancies. This immune memory may promote the successful outcome of subsequent pregnancies or - if missing or compromised - account for a risk perpetuation of pregnancy complications.

Effects of Bariatric Surgery on Maternal and Infant Outcomes of Pregnancy-An Evidence Analysis Center Systematic Review

BACKGROUND

While obesity presents specific acute and long-term risks to the pregnant woman and her offspring, the effects of bariatric surgery on pregnancy outcomes are undetermined.

OBJECTIVE

A systematic review was performed according to the Academy of Nutrition and Dietetics Evidence Analysis Library process to determine the effects of bariatric surgery on both maternal and infant health outcomes of pregnancy.

DESIGN

A comprehensive literature search of PubMed was conducted to identify studies published from years 2000 to 2015 that examined the health effects of pregnancy after bariatric surgery. Experimental studies and observational studies with a control group were included.

MAIN OUTCOME MEASURES

Outcomes of interest were gestational weight gain, maternal complications (ie, gestational diabetes, pre-eclampsia, eclampsia, hypertension, and postpartum hemorrhage), miscarriage and/or stillbirth, cesarean section, birth weight in grams, birth weight in categories (ie, macrosomia, low birth weight, small for gestational age, and large for gestational age), gestational age and preterm birth, infant illness and complications (ie, perinatal death, admission to neonatal intensive care unit, neonatal illness, and congenital malformation rates), and Apgar scores.

RESULTS

Thirteen of 246 studies were included. Compared to body mass index-matched controls without surgery, bariatric surgery before pregnancy reduced infant birth weight in grams, with no effect on total maternal gestational weight gain or Apgar scores. Surgery did not increase risk of adverse outcomes, such as miscarriage and/or stillbirth, preterm birth, or infant complications. Effects of surgery on maternal complications, infant birth weight categories, and surgical delivery rates were inconsistent.

CONCLUSIONS

Bariatric surgery is a successful treatment of maternal obesity, but certain surgery-specific risks may exist. More data are needed to determine clinical guidelines. The long-term effects of surgery on pregnancy outcomes are unknown.

Short interpregnancy intervals and adverse perinatal outcomes in high-resource settings: An updated systematic review

BACKGROUND

This systematic review summarises association between short interpregnancy intervals and adverse perinatal health outcomes in high-resource settings to inform recommendations for healthy birth spacing for the United States.

METHODS

Five databases and a previous systematic review were searched for relevant articles published between 1966 and 1 May 2017. We included studies meeting the following criteria: (a) reporting of perinatal health outcomes after a short interpregnancy interval since last livebirth; (b) conducted within a high-resource setting; and (c) estimates were adjusted for maternal age and at least one socio-economic factor.

RESULTS

Nine good-quality and 18 fair-quality studies were identified. Interpregnancy intervals <6 months were associated with a clinically and statistically significant increased risk of adverse outcomes in studies of preterm birth (eg, aOR ≥ 1.20 in 10 of 14 studies); spontaneous preterm birth (eg, aOR ≥ 1.20 in one of two studies); small-for-gestational age (eg, aOR ≥ 1.20 in 5 of 11 studies); and infant mortality (eg, aOR ≥ 1.20 in four of four studies), while four studies of perinatal death showed no association. Interpregnancy intervals of 6-11 and 12-17 months generally had smaller point estimates and confidence intervals that included the null. Most studies were population-based and few included adjustment for detailed measures of key confounders.

CONCLUSIONS

In high-resource settings, there is some evidence showing interpregnancy intervals <6 months since last livebirth are associated with increased risks for preterm birth, small-for-gestational age and infant death; however, results were inconsistent. Additional research controlling for confounding would further inform recommendations for healthy birth spacing for the United States.

Gestational Weight Gain and Maternal and Neonatal Outcomes in Underweight Pregnant Women: A Population-Based Historical Cohort Study

Objective Limited data are available that estimate the effect of gestational weight gain on maternal and neonatal outcomes in underweight women according to revised 2009 Institute of Medicine (IOM) guidelines. Methods A population-based historical cohort study of 21,674 underweight women in Missouri delivering liveborn, singleton, term infants in 2002-2008 was conducted. Adjusted odds ratios were calculated for gestational weight gain categories with multiple logistic regression, using the 2009 IOM recommended 28-40 pounds as the reference group. Results Women gaining >40 pounds compared to women gaining 28-40 pounds had significantly higher odds for preeclampsia (aOR 1.94, 95% CI 1.56-2.42, p < 0.001), cesarean delivery (aOR 1.40, 95% CI 1.28-1.53, p < 0.001), large-for-gestational-age (LGA) infant (aOR 2.32, 95% CI 2.00-2.70, p < 0.001), and 1 min APGAR score <4 (aOR 1.36, 95% CI 1.01-1.83, p < 0.05) and significantly lower odds for small-for-gestational-age (SGA) infant (aOR 0.53, 95% CI 0.48-0.59, p < 0.001). Women gaining <28 pounds compared to women gaining 28-40 pounds had significantly higher odds for SGA infant (aOR 1.85, 95% CI 1.69-2.03, p < 0.001) and significantly lower odds for preeclampsia (aOR 0.72, 95% CI 0.53-0.96, p < 0.05) and LGA infant (aOR 0.50, 95% CI 0.39-0.63, p < 0.001). Conclusion Women gaining more than the IOM recommendation were at higher risk for many adverse outcomes, but at lower risk for SGA infants. Women gaining less than the IOM recommendation were at higher risk for SGA infants but were protective for preeclampsia and LGA infants. Prospective studies of other short- and long-term maternal/infant outcomes are needed to evaluate the efficacy of the IOM guideline.

Risk of recurrence of small-for-gestational-age foetus after first pregnancy

The aim of this study was to assess the incidence of and to analyse factors related to the recurrence of small-for-gestational-age (SGA) neonates in the second pregnancy. A prospective observational study was conducted at a tertiary university hospital in Granada, Spain. A total of 7896 women who delivered their first and second singleton pregnancies at the hospital from 2003-2013 were included and evaluated all birth weights. Women whose first pregnancy was complicated by a SGA birth had a fivefold increased risk of recurrence (23.6% vs. 5.7%, p < .001). Multivariate analyses revealed that only SGA at first birth retained a statistically significant relationship, revealing that the other variables (maternal age, gestational age, interdelivery interval, maternal pre-pregnancy body mass index, occupation of the mother, smoking, hypertension, and diabetes mellitus) were confounders. Prevention of SGA in subsequent pregnancies by modification of established risk factors could be of limited utility based on the present results, supporting a genetic contribution to SGA recurrence. Impact statement The results support a genetic contribution on recurrence of SGA.

Maternal Smoking Status in Successive Pregnancies and Risk of Having a Small for Gestational Age Infant

BACKGROUND

Smoking during pregnancy is linked to having a small for gestational age (SGA) baby. We estimated SGA risk among women who smoked persistently, quit smoking or started smoking during their first two pregnancies.

METHODS

Data from the population-based Medical Birth Registry of Norway was used to evaluate self-reported smoking at the beginning and end of two successive pregnancies among 118 355 Nordic women giving birth 1999-2014. Relative risks (RR) with 95% confidence intervals (CI) of SGA in the second pregnancy were estimated using adjusted generalised linear models with non-smokers during both pregnancies serving as referent category.

RESULTS

Daily smokers throughout both pregnancies had almost threefold increased SGA risk in the second pregnancy (RR 2.9, 95% CI 2.7, 3.1). Daily smokers in the first pregnancy, who abstained in the second, had a 1.3-fold increased risk (95% CI 1.1, 1.5). Intermediate risks were found among persistent daily smokers who quit by the end of the second pregnancy (RR 2.0, 95% CI 1.6, 2.4) and non-smokers in first pregnancy who smoked daily throughout their second (RR 1.8, 95% CI 1.4, 2.3). Persistently smoking women without SGA in first pregnancy, had a 2.7-fold increased risk of SGA in second pregnancy (95% CI 2.5, 3.0).

CONCLUSIONS

Smoking throughout two successive pregnancies was associated with the greatest increased SGA risk compared with non-smokers, while cessation before or during the second pregnancy reduced this risk. Women who smoked in the first pregnancy without experiencing SGA are not protected against SGA in second pregnancy if they continue smoking.

Relationship between maternal hypoglycaemia and small-for-gestational-age infants according to maternal weight status: a retrospective cohort study in two hospitals

OBJECTIVE

The relationship between pre-pregnancy body mass index (BMI) and low glucose challenge test (GCT) results by maternal weight status has not been examined. This study aimed to clarify the relationship between a low GCT result and small for gestational age (SGA) by maternal weight status.

DESIGN

A retrospective cohort study in 2 hospitals.

SETTING

This study evaluated the obstetric records of women who delivered in a general community hospital and a tertiary perinatal care centre.

PARTICIPANTS

The number of women who delivered in both hospitals between January 2012 and December 2013 and underwent GCT between 24 and 28 weeks of gestation was 2140. Participants with gestational diabetes mellitus or diabetes during pregnancy, and GCT results of ≥140 mg/dL were excluded. Finally, 1860 women were included in the study.

PRIMARY AND SECONDARY OUTCOME MEASURES

The participants were divided into low-GCT (≤90 mg/dL) and non-low-GCT groups (91-139 mg/dL). The χ² tests and multivariate logistic regression analyses were conducted to investigate the association between low GCT results and SGA by maternal weight status.

RESULTS

The incidence of SGA was 11.4% (212/1860), and 17.7% (330/1860) of the women showed low GCT results. The patients were divided into 3 groups according to their BMI (underweight, normal weight and obese). When the patients were analysed separately by their weight status after controlling for maternal age, pre-pregnancy maternal weight, maternal weight gain during pregnancy, pregnancy-induced hypertension, thyroid disease and difference in hospital, low GCT results were significantly associated with SGA (OR 2.10; 95% CI 1.14 to 3.89; p=0.02) in the underweight group.

CONCLUSIONS

Low GCT result was associated with SGA at birth among underweight women. Examination of maternal glucose tolerance and fetal growth is necessary in future investigations.

Association of previous severe low birth weight with adverse perinatal outcomes in a subsequent pregnancy among HIV-prevalent urban African women

OBJECTIVE

To evaluate the association between severity of prior low birth weight (LBW) delivery and adverse perinatal outcomes in the subsequent delivery among an HIV-prevalent urban African population.

METHODS

A retrospective cohort study was conducted among 41 109 women who had undergone two deliveries in Lusaka, Zambia, between February 1, 2006, and May 31, 2013. The relationship between prior LBW delivery (<2500 g) and a composite measure of adverse perinatal outcome in the second pregnancy was assessed using multivariate logistic regression.

RESULTS

Women with prior LBW delivery (n=4259) had an increased risk of LBW in the second delivery versus those without prior LBW delivery (n=37 642). Such risk correlated with the severity of first delivery LBW. The adjusted odds ratio (AOR) was 2.89 (95% confidence interval [CI] 2.05-4.09) for a birth weight of 1000-1499 g, 3.05 (95% CI 2.42-3.86) for a birth weight of 1500-1999 g, and 2.02 (95% CI 1.81-2.27) for a birth weight of 2000-2499 g. Previous LBW delivery also increased the risk of adverse perinatal outcome, with an AOR of 1.4 (95% CI 1.2-1.7).

CONCLUSION

Severe prior LBW delivery conferred substantial risk for adverse perinatal outcomes in a subsequent pregnancy.

Pregnancy loss history at first parity and selected adverse pregnancy outcomes

PURPOSE

To evaluate the association between pregnancy loss history and adverse pregnancy outcomes.

METHODS

Pregnancy history was captured during a computer-assisted personal interview for 21,277 women surveyed in the National Survey of Family Growth (1995-2013). History of pregnancy loss (<20 weeks) at first parity was categorized in three ways: number of losses, maximum gestational age of loss(es), and recency of last pregnancy loss. We estimated risk ratios for a composite measure of selected adverse pregnancy outcomes (preterm, stillbirth, or low birthweight) at first parity and in any future pregnancy, separately, using predicted margins from adjusted logistic regression models.

RESULTS

At first parity, compared with having no loss, having 3+ previous pregnancy losses (adjusted risk ratio (aRR) = 1.66 [95% CI = 1.13, 2.43]), a maximum gestational age of loss(es) at ≥10 weeks (aRR = 1.28 [1.04, 1.56]) or having experienced a loss 24+ months ago (aRR = 1.36 [1.10, 1.68]) were associated with increased risks of adverse pregnancy outcomes. For future pregnancies, only having a history of 3+ previous pregnancy losses at first parity was associated with increased risks (aRR = 1.97 [1.08, 3.60]).

CONCLUSION

Number, gestational age, and recency of pregnancy loss at first parity were associated with adverse pregnancy outcomes in U.S. women.

Inter-Pregnancy Weight Change and the Risk of Recurrent Pregnancy Complications

Women with specific adverse pregnancy outcomes in their first pregnancy may be receptive to inter-pregnancy weight management guidance aimed at preventing these complications reoccurring in subsequent pregnancies. Thus the association between inter-pregnancy weight change and the risk of recurrent pregnancy complications at the second pregnancy was investigated in a retrospective cohort study of 24,520 women with their first-ever and second consecutive deliveries in Aberdeen using logistic regression. Compared with women who were weight stable, weight loss (>2BMI units) between pregnancies was associated with an increased risk of recurrent small for gestational age (SGA) birth and elective Cesarean-section, and was protective against recurrent pre-eclampsia, placental oversize and large for gestational age (LGA) birth. Conversely weight gain (>2BMI units) between pregnancies increased the risk of recurrent gestational hypertension, placental oversize and LGA birth and was protective against recurrent low placental weight and SGA birth. The relationships between weight gain, and placental and birth weight extremes were evident only in women with a healthy weight at first pregnancy (BMI<25units), while that between weight gain and the increased risk of recurrent gestational hypertension was largely independent of first pregnancy BMI. No relationship was detected between inter-pregnancy weight change and the risk of recurrent spontaneous preterm delivery, labour induction, instrumental delivery, emergency Cesarean-section or postpartum hemorrhage. Therefor inter-pregnancy weight change impacts the risk of recurrent hypertensive disorders, SGA and LGA birth and women with a prior history of these specific conditions may benefit from targeted nutritional advice to either lose or gain weight after their first pregnancy.

Maternal and placental risk factors for light-for-gestational-age births

AIM

We conducted a cross-sectional study to investigate risk factors for births of light-for-gestational-age (LGA) infants.

METHODS

A survey was conducted at the Department of Obstetrics and Gynecology at Sapporo Medical University Hospital in Sapporo, Japan from 2013 to 2014. LGA and appropriate for gestational age (AGA) are defined as having a birthweight below the 10th percentile and between the 10th percentile and 90th percentile for gestational age at birth in the population standard of gestational age, sex, and parity, respectively. An odds ratio (OR) and its 95% confidence interval (95%CI) for LGA were calculated by analysis using the logistic regression model.

RESULTS

In total, 307 inpatients (94.2%) participated in the study out of 326 consecutive post-partum inpatients. Among them, 37 infants and 237 infants were classified into the LGA and AGA groups, respectively. As a result of multivariable analysis, prevalence of gestational hypertension (OR = 8.96, 95%CI 1.81-44.35) and the presence of placental infarction (OR = 9.65, 95%CI 1.76-53.01) were significantly associated with an increased risk of LGA. Placentas weighing 510-603 g and ≥604 g were significantly associated with reduced risk of LGA (OR = 0.04, 95%CI 0.01-0.29 and OR = 0.03, 95%CI 0.01-0.32, respectively), and higher placental weights were significantly observed in the trend for reduced LGA risk (P for trend < 0.001).

CONCLUSION

We found that the prevalence of gestational hypertension, lower placental weight, and the presence of placental infarctions were all independently associated with the risk of LGA. Placental abnormalities may be etiologically important for LGA risk, though further research is necessary.

Using Electronic Health Records for Population Health Research: A Review of Methods and Applications

The use and functionality of electronic health records (EHRs) have increased rapidly in the past decade. Although the primary purpose of EHRs is clinical, researchers have used them to conduct epidemiologic investigations, ranging from cross-sectional studies within a given hospital to longitudinal studies on geographically distributed patients. Herein, we describe EHRs, examine their use in population health research, and compare them with traditional epidemiologic methods. We describe diverse research applications that benefit from the large sample sizes and generalizable patient populations afforded by EHRs. These have included reevaluation of prior findings, a range of diseases and subgroups, environmental and social epidemiology, stigmatized conditions, predictive modeling, and evaluation of natural experiments. Although studies using primary data collection methods may have more reliable data and better population retention, EHR-based studies are less expensive and require less time to complete. Future EHR epidemiology with enhanced collection of social/behavior measures, linkage with vital records, and integration of emerging technologies such as personal sensing could improve clinical care and population health.

Smoking prevalence, reduction, and cessation during pregnancy and associated factors: a cross-sectional study in public maternities, Rio de Janeiro, Brazil

Background

Smoking epidemic in Brazilian women has later onset, smaller magnitude, and slower decreasing trend, compared to men. Among pregnant women, smoking has an additional deleterious effect. The purpose of this study was to analyze smoking prevalence during pregnancy and associated factors, and to describe the frequency of smoking reduction and cessation in public maternities of Rio de Janeiro State, southeastern Brazil, in 2011.

Methods

A cross-sectional study was conducted in two maternities located at public hospitals in two cities of the Rio de Janeiro state, Niterói (maternity A) and of Rio de Janeiro (maternity B). Data were gathered by interviews 12 hours after the delivery, and analyses of prenatal cards and medical records. Smoking prevalence according to maternal characteristics, adequacy of prenatal care, and proportions of smoking reduction and cessation during pregnancy were calculated. Factors associated to smoking during pregnancy were estimated by logistic regression analysis.

Results

Smoking prevalence at maternity A (24.8%, 95% CI: 21.1-29.0) and maternity B (17.9%, 95% CI: 15.8-20.1) were high. Prevalence rates were greater in women aged 20-34 years, mainly without partner, multiparous and brown or black skin color. Low education (OR = 2.14, 95% CI 1.21, 3.79) and multiparity (OR = 3.48, 95% CI 1.78, 6.81), at maternity A; adolescence (OR = 0.44, 95% CI 0.26, 0.75), black skin color (OR = 1.71, 95% CI 1.06, 2.74), low education (OR = 1.61, 95% CI 1.08, 2.40), and multiparity (OR = 1.58, 95% CI 1.03, 2.44), at maternity B, were associated with smoking in multivariable analysis. Adequacy of prenatal care and smoking prevalence showed an inverse association. More than half of the smokers kept the smoking habits during pregnancy. Reduction occurred mainly between the 1^st and 2^nd trimesters of pregnancy.

Conclusion

Smoking prevalence during pregnancy was higher for multiparous and less educated women. Population and individual strategies for smoking prevention and control must include actions specific for women, especially during the reproductive period.