Maternal pre-pregnancy BMI influences the associations between bisphenol and phthalate exposures and maternal weight changes and fat accumulation

BACKGROUND

Bisphenols and phthalates are two classes of endocrine-disrupting chemicals (EDCs) thought to influence weight and adiposity. Limited research has investigated their influence on maternal weight changes, and no prior work has examined maternal fat mass. We examined the associations between exposure to these chemicals during pregnancy and multiple maternal weight and fat mass outcomes.

METHODS

This study included a sample of 318 women enrolled in a Canadian prospective pregnancy cohort. Second trimester urinary concentrations of 2 bisphenols and 12 phthalate metabolites were quantified. Self-reported and measured maternal weights and measured skinfold thicknesses were used to calculate gestational weight gain, 3-months and 3- to 5-years postpartum weight retention, late pregnancy fat mass gain, total postpartum fat mass loss, and late postpartum fat mass retention. Adjusted robust regressions examined associations between chemicals and outcomes in the entire study population and sub-groups stratified by pre-pregnancy body mass index (BMI). Bayesian kernel machine regression examined chemical mixture effects.

RESULTS

Among women with underweight or normal pre-pregnancy BMIs, MBzP was negatively associated with weight retention at 3- to 5-years postpartum (B = -0.04, 95%CI: -0.07, -0.01). Among women with overweight or obese pre-pregnancy BMIs, MEHP and MMP were positively associated with weight retention at 3-months and 3- to 5-years postpartum, respectively (B's = 0.12 to 0.63, 95%CIs: 0.02, 1.07). DEHP metabolites and MCNP were positively associated with late pregnancy fat mass gain and late postpartum fat mass retention (B's = 0.04 to 0.18, 95%CIs: 0.001, 0.32). Further, the mixture of EDCs was positively associated with late pregnancy fat mass gain.

CONCLUSION

In this cohort, pre-pregnancy BMI was a key determinant of the associations between second trimester exposure to bisphenols and phthalates and maternal weight changes and fat accumulation. Investigations of underlying physiological mechanisms, windows of susceptibility, and impacts on maternal and infant health are needed.

Effect of Maternal Pre-Pregnancy Body Mass Index on Longitudinal Fetal Growth and Mediating Role of Maternal Fasting Plasma Glucose: A Retrospective Cohort Study

Purpose

To assess the impact of maternal pre-pregnancy body mass index (BMI) on longitudinal fetal growth, and the potential mediation effect of the maternal fasting plasma glucose in first trimester.

Methods

In this retrospective cohort study, we collected pre-pregnancy BMI data and ultrasound measurements during pregnancy of 3879 singleton pregnant women who underwent antenatal examinations and delivered at Peking Union Medical College Hospital. Generalized estimation equations, linear regression, and logistic regression were used to examine the association between pre-pregnancy BMI with fetal growth and adverse neonatal outcomes. Mediation analyses were also used to examine the mediating role of maternal fasting plasma glucose (FPG) in first trimester.

Results

A per 1 Kg/m² increase in pre-pregnancy BMI was associated with increase fetal body length Z-score (β 0.010, 95% CI 0.001, 0.019) and fetal body weight (β 0.017, 95% CI 0.008, 0.027). In mid pregnancy, pre-pregnancy BMI also correlated with an increase Z-score of fetal abdominal circumference, femur length (FL). Pre-pregnancy BMI was associated with an increased risk of large for gestational age and macrosomia. Mediation analysis indicated that the associations between pre-pregnancy BMI and fetal weight in mid and late pregnancy, and at birth were partially mediated by maternal FPG in first trimester (mediation proportion: 5.0%, 8.3%, 1.6%, respectively).

Conclusion

Maternal pre-pregnancy BMI was associated with the longitudinal fetal growth, and the association was partly driven by maternal FPG in first trimester. The study emphasized the importance of identifying and managing mothers with higher pre-pregnancy BMI to prevent fetal overgrowth.

Is the association between mothers' autistic traits and childhood autistic traits moderated by maternal pre-pregnancy body mass index?

BACKGROUND

Previous studies showed that there is a positive association between mothers' and children's autistic traits. We also tested if this association is more pronounced in mothers with a higher pre-pregnancy body mass index (BMI).

METHOD

The study was embedded in two cohorts with information available for 4,659 participants from the Generation R and for 179 participants from the Cambridge Ultrasound Siblings and Parents Project (CUSP) cohort. In both cohorts, maternal autistic traits were assessed using the short form of the Autism Spectrum Quotient, and information about maternal height and weight before pregnancy was obtained by questionnaire. Child autistic traits were assessed with the short form of Social Responsiveness Scale in Generation R (M = 13.5 years) and with the Quantitative Checklist for Autism in Toddlers (Q-CHAT) in the CUSP cohort (M = 1.6 years).

RESULT

Higher maternal autistic traits were associated with higher autistic traits in toddlerhood (CUSP cohort; βadjusted = 0.20, p < 0.01), in early childhood (Generation R; βadjusted = 0.19, p < 0.01), and in early adolescence (Generation R; βadjusted = 0.16, p < 0.01). Furthermore, a higher maternal pre-pregnancy BMI was associated with higher child autistic traits, but only in Generation R (βadjusted = 0.03, p < 0.01). There was no significant moderating effect of maternal pre-pregnancy BMI on the association between autistic traits of mothers and children, neither in Generation R nor in CUSP. In addition, child autistic traits scores were significantly higher in mothers who were underweight and in mothers who were overweight compared to mothers with a healthy weight.

CONCLUSION

We confirm the association between maternal and child autistic traits in toddlerhood, early childhood, and early adolescence. Potential interacting neurobiological processes remain to be confirmed.

Maternal cardiovascular disorders before and during pregnancy and offspring cardiovascular risk across the life course

Obesity, hypertension, type 2 diabetes mellitus and dyslipidaemia are highly prevalent among women of reproductive age and contribute to complications in >30% of pregnancies in Western countries. An accumulating body of evidence suggests that these cardiovascular disorders in women, occurring before and during their pregnancy, can affect the development of the structure, physiology and function of cardiovascular organ systems at different stages during embryonic and fetal development. These developmental adaptations might, in addition to genetics and sociodemographic and lifestyle factors, increase the susceptibility of the offspring to cardiovascular disease throughout the life course. In this Review, we discuss current knowledge of the influence of maternal cardiovascular disorders, occurring before and during pregnancy, on offspring cardiovascular development, dysfunction and disease from embryonic life until adulthood. We discuss findings from contemporary, large-scale, observational studies that provide insights into specific critical periods, evidence for causality and potential underlying mechanisms. Furthermore, we focus on priorities for future research, including defining optimal cardiovascular and reproductive health in women and men before their pregnancy and identifying specific embryonic, placental and fetal molecular developmental adaptations from early pregnancy onwards. Together, these approaches will help stop the intergenerational cycle of cardiovascular disease.

The Association of Maternal Height With Mode of Delivery and Fetal Birth Weight at King Abdulaziz University Hospital, Jeddah, Saudi Arabia

Study Objectives: The aim of this study was to find if there is an association between maternal height and mode of delivery, as well as an association between maternal height and baby’s weight as a secondary outcome.

Method: This retrospective record review was performed at King Abdulaziz University Hospital (KAUH), Jeddah, Saudi Arabia, including patients admitted between January 2016 to December 2017. All nulligravida with singleton term pregnancies who gave birth were included in this study. Pregnant women with planned elective cesarean section (CS) and incomplete records were excluded. The maternal demographic and clinical data (age, height, weight, hypertension, gestational diabetes (GDM), body mass index (BMI), smoking status, gestational age, regional analgesia during delivery, type of delivery, postpartum hemorrhage (PPH), and episiotomy), neonatal birth weight, and Apgar score were obtained from KAUH computerized records. Our primary outcome was the mode of delivery. The secondary outcome was the classification of neonatal weight into small for gestational age (SGA), appropriate for gestational age (AGA), or large for gestational age (LGA). Maternal height was divided into seven groups. Descriptive statistics using mean and standard deviation were used for continuous variables. Frequencies and percentages were used for categorical variables. Student's t-test and chi-square tests were used to evaluate the differences between continuous and categorical variables.

Result: A total of 1067 women were included in this study. Most were at 40 weeks of gestation age (14.9%) with a mean height of 156.4±6.2 cm. Of the total, 76.9% were spontaneous vaginal delivery without operative assistance, 15.9% were delivered via CS, and 7.2% delivered vaginally with the assistance of forceps or ventouse. The mean neonatal birth weight was 2994 ± 451 gms with most neonates (87.3%) having a birth weight between 2500 and 4000 gms. Most babies were of average weight for their gestational age at delivery. There was a significant negative association between maternal height with CS (p=0.017). Moreover, there was a correlation between maternal height and the baby’s birth weight (p=0.01), and we found that for every 1 cm increase in women’s height, the baby's weight increases by 12.8 gms.

Conclusion: Our study didn’t find an association between maternal height and vaginal delivery or operative vaginal delivery. However, there was an impact of maternal height on CS delivery. Therefore, we suggest screening for short maternal height as they have an increased risk of having an emergency CS. In our secondary outcome, we found a positive association between maternal height and baby's birth weight.

Simple method for identification of women at risk of gestational diabetes mellitus in Arusha urban, Tanzania

BACKGROUND

Screening for gestational diabetes mellitus in Tanzania is challenged by limited resources. Therefore, this study aimed to develop a simple method for identification of women at risk of gestational diabetes mellitus in Arusha urban, Tanzania.

METHODS

This study used data from a cross sectional study, that was conducted between March and December 2018 in Arusha District involving 468 pregnant women who were not known to have diabetes before pregnancy. Urine glucose was tested using urine multistics and blood glucose levels by Gluco-Plus™ and diagnosed in accordance with the World Health Organization's criteria. Anthropometrics were measured using standard procedures and maternal characteristics were collected through face-to-face interviews using a questionnaire with structured questions. Univariate analysis assessed individual variables association with gestational diabetes mellitus where variables with p-value of < 0.05 were included in multivariable analysis and predictors with p-value < 0.1 remained in the final model. Each variable was scored based on its estimated coefficients and risk scores were calculated by multiplying the corresponding coefficients by ten to get integers. The model's performance was assessed using c-statistic. Data were analyzed using Statistical Package for Social Science™.

RESULTS

The risk score included body fat ≥ 38%, delivery to macrosomic babies, mid-upper arm circumference ≥ 28 cm, and family history of type 2 diabetes mellitus. The score correctly identified 98% of women with gestational diabetes with an area under the receiver operating characteristic curve of 0.97 (95% CI 0.96-0.99, p < 0.001), sensitivity of 0.98, and specificity of 0.46.

CONCLUSION

The developed screening tool is highly sensitive and correctly differentiates women with and without gestational diabetes mellitus in a Tanzanian sub-population.

Sex-dependent influence of maternal predictors on fetal anthropometry in pregnancies with gestational diabetes mellitus

Background

Third trimester fetal anthropometric parameters are known to predict neonatal complications. A better understanding of predictors of adverse fetal parameters might help to personalize the use and frequency of fetal ultrasound. The objectives of this study were:

(a) to evaluate the utility of maternal sociodemographic, anthropometric and metabolic predictors to predict 3^rd trimester fetal anthropometric parameters in women with gestational diabetes mellitus (GDM),

(b) to assess whether the impact of these maternal predictors is fetal sex-dependent, and

(c) to provide a risk stratification for markers of fetal overgrowth (fetal weight centile (FWC) and fetal abdominal circumference centile (FACC) depending on prepregnancy BMI and gestational weight gain (GWG) until the 1^st GDM visit.

Methods

This prospective study included 189 women with GDM. Maternal predictors were age, ethnicity, prepregnancy BMI, GWG and excessive weight gain until the 1^st GDM visit, fasting, 1-hour and 2-hour blood glucose oral glucose tolerance test values, HbA1c at the 1^st visit and medical treatment requirement. Fetal outcomes included FWC, FWC >90% and <10%, FACC, FACC >90% and <10%, at 29 0/7 to 35 6/7 weeks of gestational age. We performed univariate and multivariate regression analyses and probability analyses.

Results

In multivariate analyses, prepregnancy BMI was associated with FWC, FWC > 90% and FACC. GWG until the 1^st GDM visit was associated with FWC, FACC and FACC > 90% (all p ≤ 0.045). Other maternal parameters were not significantly associated with fetal anthropometry in multivariate analyses (all p ≥ 0.054). In female fetuses, only GWG was associated with FACC (p= 0.044). However, in male fetuses, prepregnancy BMI was associated with FWC, FWC > 90% and FACC and GWG with FWC in multivariate analyses (all p ≤ 0.030). In women with a prepregnancy BMI of ≥ 25 kg/m² and a GWG until the 1^st GDM visit ≥ 10.3 kg (mean GWG), the risk for FWC > 90% and FACC > 90% was 5.3 and 4 times higher than in their counterparts.

Conclusions

A personalized fetal ultrasound surveillance guided by fetal sex, prepregnancy BMI and GWG may be beneficial in reducing adverse fetal and neonatal outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04767-z.

Fetomaternal Expression of Glucose Transporters (GLUTs)-Biochemical, Cellular and Clinical Aspects

Several types of specialized glucose transporters (GLUTs) provide constant glucose transport from the maternal circulation to the developing fetus through the placental barrier from the early stages of pregnancy. GLUT1 is a prominent protein isoform that regulates placental glucose transfer via glucose-facilitated diffusion. The GLUT1 membrane protein density and permeability of the syncytial basal membrane (BM) are the main factors limiting the rate of glucose diffusion in the fetomaternal compartment in physiological conditions. Besides GLUT1, the GLUT3 and GLUT4 isoforms are widely expressed across the human placenta. Numerous medical conditions and molecules, such as hormones, adipokines, and xenobiotics, alter the GLUT's mRNA and protein expression. Diabetes upregulates the BM GLUT's density and promotes fetomaternal glucose transport, leading to excessive fetal growth. However, most studies have found no between-group differences in GLUTs' placental expression in macrosomic and normal control pregnancies. The fetomaternal GLUTs expression may also be influenced by several other conditions, such as chronic hypoxia, preeclampsia, and intrahepatic cholestasis of pregnancy.

Testing the assumptions of customized intrauterine growth charts using national birth studies

INTRODUCTION

Customized intrauterine growth charts are widely used for growth monitoring and research. They are based on three assumptions: (1) estimated fetal weight (EFW) has a normal distribution with a constant coefficient of variation at all gestational ages; (2) Hadlock's growth curve accurately describes the relation between EFW and gestational ages; (3) associations between EFW and the fetal and maternal characteristics included in the customization model (fetal sex, pre-pregnancy weight, height, parity) are proportional throughout pregnancy. The aim of this study was to test whether these underlying assumptions are verified.

MATERIAL AND METHODS

Data came from (1) the French Longitudinal Study of Children (ELFE) cohort, which recruited births after 32 weeks' gestation in 349 maternity hospitals in France in 2011, and (2) the National Perinatal Survey, which included births from all French maternity hospitals in 2016. The study population included, respectively, 6 920 and 8 969 singleton non-malformed term live births with data on customization characteristics and EFW. We computed the coefficient of variation by gestational age and then modeled the association of gestational age, maternal and fetal characteristics with EFW at the second and third trimester ultrasound and with birthweight using linear regression. To assess the proportionality of the impact of maternal and fetal characteristics, we computed the percent change in weight associated with these characteristics at these three time points.

RESULTS

The coefficient of variation was close to 12% at each gestational age, but EFW was not normally distributed, leading to small but systematic underestimation of fetuses under the 10th percentile. Weights representing the 50th and 10th percentiles based on Hadlock's growth trajectory were lower than observed or predicted weights. Most characteristics more strongly impacted weight at birth than during pregnancy. In the French Longitudinal study of Children (ELFE) cohort, boys were 1.8% (95% confidence interval [CI] 1.3-2.4) heavier than girls in the third trimester, whereas this percentage was 4.6% (95% CI 4.0-5.2) at birth. In the National Perinatal Survey, these percentages were 2.3% (95% CI 1.8-2.8) and 4.3% (95% CI 3.8-4.8).

CONCLUSIONS

These results from two independent sources revealed discrepancies between routine clinical EFW data used for growth monitoring and the customized growth model's assumptions.

Sex-specific association of high maternal psychological stress during pregnancy on newborn birthweight

Birthweight is an important predictor of newborn health and has been linked to maternal psychological stress during pregnancy. However, it is unclear whether prenatal stress affects birthweight similarly for both male and female infants. We used a well-established pregnancy cohort to investigate the impact of high maternal psychological stress during pregnancy on birthweight as a function of infant sex. Overall, 5702 mother-newborn pairs were analysed. Of these, 198 mothers reported high levels of stress using the Psychological Stress Measure (nine-items version; PSM-9). Maternal psychological stress was assessed between the 24^th and 28^th week of gestation and analyses were performed jointly and independently as a function of neonatal sex (separate analyses for male and female infants). Newborns exposed to high maternal psychological stress during pregnancy (a score above 26 measured using the PSM-9 questionnaire, corresponding to >97.5^th percentile) were compared to newborns of mothers who reported lower stress. ANCOVAs revealed that high levels of maternal stress during pregnancy were linked to infant birthweight as a function of infant sex. Male infants of mothers who reported high levels of stress had a greater birthweight whereas female infants had a lower birthweight under the same conditions, in comparison to mothers who did not report greater levels of stress. Although the effect size is small, these results underline the possibility that male and female fetuses may use different strategies when adapting to maternal adversity and highlight the need to consider infant sex as a moderator of the association between maternal psychological stress during pregnancy and infant birthweight.

Periconceptional maternal body mass index and the impact on post-implantation (sex-specific) embryonic growth and morphological development

OBJECTIVE

Women with obesity have an increased risk of pregnancy complications. Although complications generally present in the second and third trimester of pregnancy, most of them develop in the periconception period. Moreover, fetal sex also impacts pregnancy course and outcome. Therefore, our aim is to study (sex-specific) associations between periconceptional maternal body mass index (BMI) and embryonic growth and morphological development.

METHODS

A total of 884 women with singleton pregnancies were selected from the Rotterdam Periconception Cohort, comprising 15 women with underweight, 483 with normal weight, 231 with overweight and 155 with obesity. Longitudinal three-dimensional ultrasound examinations were performed at 7, 9, and 11 weeks of gestation for offline measurements of crown-rump length (CRL), embryonic volume (EV), and Carnegie stages. Analyses were adjusted for maternal age, parity, ethnicity, education, and periconceptional lifestyle.

RESULTS

A negative trend was observed for embryos of women with obesity (β_EV -0.03, p = 0.086), whereas embryonic growth and developmental trajectories in women with overweight were comparable to those with normal weight. Maternal underweight was associated with faster morphological development (β_Carnegie 0.78, p = 0.004). After stratification for fetal sex, it was demonstrated that female embryos of underweight women grow and morphologically develop faster than those of normal weight women (β_EV 0.13, p = 0.008; β_Carnegie 1.39, p < 0.001), whereas female embryos of women with obesity grow slower (β_EV -0.05, p = 0.027).

CONCLUSION

We found that periconceptional maternal underweight is associated with faster embryonic growth, especially in females. In contrast, female embryos of women with obesity grow slower than female embryos of women with normal weight. This may be the result of altered female adaptation to the postnatal environment. Future research should focus on strategies for optimizing preconceptional maternal weight, to reduce BMI-related pregnancy complications and improve the health of future generations.

Coping with Stress in Complicated Pregnancy and Gestational Weight Gain

Maternal obesity is one of the leading health problems in the world. Excessive gestational weight gain (GWG) can lead to many complications during pregnancy, especially when it is accompanied by diabetes. Moreover, the risk of excessive GWG in pregnant women is significant, irrespective of prenatal counseling. Studies on this subject concerning coping with stress are lacking in the literature. The present work is aimed at evaluating the styles of coping with stress and their relation to GWG in pregnant women with gestational diabetes (GDM) for whom sudden adaptation to dietary management during this period can be challenging. It was indicated that women with GDM reported high stress related to potential maternal-fetal complications and worries about compliance with dietary management. The overall weight gain of participants in pregnancy was determined in connection to their prepregnancy body mass index (BMI) and classified based on the Institute of Medicine guidelines. A standardized psychological scale was used to assess coping styles. The results showed that almost half of the participants did not meet the Institute of Medicine recommendations for weight gain during pregnancy. There were significant correlations between the styles of coping with stress and the GWG. Additionally, low correlations were indicated between emotional, avoidant, task-oriented coping styles and the age of pregnant women with GDM. Regression analysis showed that the stress-coping style that focused on emotions was the most predictive of overall weight gain. There is a need for a better understanding of psychological barriers in achieving the recommended GWG and potential limitations in providers' interventions, particularly for GDM.

Individualized birth length and head circumference percentile charts based on maternal body weight and height

Objectives Measurement of birth length and birth head circumference is part of the newborn assessment. Both measurements aid in distinguishing between proportionate and disproportionate small and large for gestational age newborns. It had been shown that birth weight is related to maternal height and weight. This study aims to analyze birth length and birth head circumference percentiles based on maternal stature. Methods This observational study analyzed birth length and birth head circumference percentiles of 2.3 million newborns stratified by maternal height and weight from the first obstetric assessment. Percentiles were calculated for sex and 22-43 gestational weeks for all infants. Eighteen subgroups based on six maternal height and three weight strata were defined and percentiles calculated from 32 to 42 gestational weeks using GAMLSS package for R. Results Newborns of mothers with height <158 cm and weight <53 kg (short stature) had a rate of preterm birth of 9%, compared to 5% in the tall stature group (height >177 cm, weight >79 kg). Small stature mothers were 1.7 years younger. Birth length differed by several centimeters for the same percentiles between groups of short and tall stature mothers, whereas birth head circumference differed up to 1.2 cm. The largest deviation of birth length was between the 97th percentiles. For male newborns born at term, birth length at the 97th percentile differed by 3.2 cm, at the 50th percentile by 2.7 cm and at the third percentile by 2.5 cm. Conclusions Birth length and birth head circumference are related to maternal height and weight. To more completely assess newborns, the maternal size should be considered.

Impact of maternal height on birthweight classification in singleton births at term: a cohort study in The Netherlands

OBJECTIVE

To assess the association between maternal height and birthweight in a healthy population and to study the effect of maternal height on the classification of birthweight as small for gestational age (SGA) and large for gestational age (LGA).

METHODS

A descriptive, observational retrospective study was conducted in a low risk population in the Netherlands. The study included term singleton healthy nonsmoking pregnant women with normal body mass index (n = 9291). We calculated the impact of maternal height on birthweight using multiple linear regression analyses with adjustment for gestational age, gender, and parity. We calculated the number of newborns classified as SGA and LGA using the cutoff point of the Dutch Birthweight chart, which does not customize for maternal height. Subsequently, we calculated the changes in classification from SGA and LGA to appropriate for gestational age (AGA) in case of customization for maternal height.

RESULTS

A significant association was found between maternal height and birthweight; 15.0 g higher birthweight per extra cm maternal height (95% confidence interval 13.8-16.1; p<.001; R² model = 0.28). The incidence of SGA was 7.1% (range 17.4-2.0% form shortest to tallest maternal height category) and of LGA 8.4% (range 1.9-21.5% from shortest to tallest maternal height category). We calculated a shift in classification: 114 newborns (17.3%) in shorter (<167 cm) women previously SGA and 165 newborns (21.1%) in taller (>173 cm) women previously LGA were classified as AGA when controlling for maternal height.

CONCLUSIONS

Maternal height is significantly associated with birthweight. Birthweight charts customized for maternal height change classification in one out of six SGA or LGA newborns at term.

Individualized sex-specific birth weight percentiles for gestational age based on maternal height and weight

OBJECTIVES

The maternal body size affects birth weight. The impact on birth weight percentiles is unknown. The objective of the study was to develop birth weight percentiles based on maternal height and weight.

METHODS

This observational study analyzed 2.2 million singletons from the German Perinatal Survey. Data were stratified into 18 maternal height and weight groups. Sex-specific birth weight percentiles were calculated from 31 to 42 weeks and compared to percentiles from the complete dataset using the GAMLSS package for R statistics.

RESULTS

Birth weight percentiles not considering maternal size showed 22% incidence of small for gestational age (SGA) and 2% incidence of large for gestational age (LGA) for the subgroup of newborns from petite mothers, compared to a 4% SGA and 26% LGA newborns from big mothers. The novel percentiles based on 18 groups stratified by maternal height and weight for both sexes showed significant differences between identical original percentiles. The differences were up to almost 800 g between identical percentiles for petite and big mothers. The 97th and 50th percentile from the group of petite mothers almost overlap with the 50th and 3rd percentile from the group of big mothers.

CONCLUSIONS

There is a clinically significant difference in birth weight percentiles when stratified by maternal height and weight. It could be hypothesized that birth weight charts stratified by maternal anthropometry could provide higher specificity and more individual prediction of perinatal risks. The new percentiles may be used to evaluate estimated fetal as well as birth weight.

Caesarean sections are associated with sonographic determined fetal size from the second trimester onwards

Human birth represents a critical and life-threatening event in the life of mother and child and is therefore of special importance for anthropological as well as public health research.

Study aims: to analyze the association patterns between fetal biometry and delivery modes from the first trimester onwards.

In this electronic medical record-based study, a dataset of 3408 singleton term birth taking place at the Viennese Danube hospital in Austria. was analyzed. Fetal biometry was reconstructed by the results of three ultrasound examinations carried out at the 11th/12th, 20th/21th and 32th/33thweek of gestation. In detail, crown-rump length, biparietal diameter, fronto-occipital diameter, head circumference, abdominal trans-verse diameter, abdominal sagittal diameter, abdominal circumference, and femur length were determined. Birth weight, birth length and head circumference were measured immediately after birth. Four delivery modes were compared: spontaneous vaginal birth, instrumental vaginal birth, planned cesarean section and emergency cesarean section.

The total cesarean section rate was 10.2%. Fetal biometry and newborn size differed significantly between the four delivery modes. From the second trimester onward, head circumferences were significantly larger (p=0.005) among fetuses delivered by instrumental delivery or emergency cesarean section than among fetuses delivered by spontaneous vaginal birth. The fetal abdominal dimensions during the third trimester were significantly largest (p=0.001) among fetuses delivered by emergency cesarean section. In comparison to spontaneous vaginal delivery the risk to require instrumental delivery increased significantly with increasing fetal head dimensions at the second (p=0.019) and third trimester(p=0.032) independent of maternal somatic factors. The risk of emergency CS increased significantly with increasing head dimensions (p=0.030) as well as abdominal dimensions (p=0.001) at the third trimester and newborn size (p=0.002), also independently of maternal somatic factors.

In general, larger fetuses are on an increased risk of experiencing instrumental delivery or emergency caesarean section. This association between fetal size and delivery mode is detectable from the second trimester onwards.

Maternal obesity and intrapartum obstetric complications among pregnant women: Retrospective cohort analysis from medical birth registry in Northern Tanzania

BACKGROUND

In the last decade, Tanzania has observed a dramatic increase in overweight and obesity among women of childbearing age, a demographic shift that has been associated with intrapartum obstetric complications in high-income countries. Similar increases in maternal morbidity including postpartum haemorrhage, hypertensive disorders of pregnancy, and rates of caesarean delivery have not yet documented in Tanzania. This analysis describes intrapartum obstetric complications associated with maternal obesity among pregnant women delivering at teaching hospital in Northern Tanzania.

METHODS

A retrospective cohort analysis was conducted using the hospital's antenatal care (ANC) and birth registries from 2000 to 2015. The World Health Organization (WHO) body mass index (BMI) categories were applied to classify BMI status of pregnant women within 16 weeks of gestational age at their first ANC visit. Relative risk (RR) of obstetric complications with corresponding 95% confidence intervals (CIs) were estimated using multivariable log-binomial regression, adjusting for clustering effect for the correlation between multiple deliveries of the same woman.

RESULTS

Among 11 873 women who delivered babies in the hospital during the study period, 3139 (26.5%) fit the definition of overweight and 1464 (12.3%) women with obesity. Compared with women with normal weight, women with obesity were at over 2.6 times at risks of experiencing pre-eclampsia/eclampsia (RR: 2.66; 95% CI, 2.08-3.40), pregnancy-induced hypertension (RR 2.13; 95% CI, 1.26-3.62), and postpartum haemorrhage (RR 1.22; 95% CI, 1.00-1.49). Additionally, women with obesity had also higher risk of either elective (RR 2.40; 95% CI, 1.88-3.06) or emergency (RR: 1.53; 95% CI, 1.34-1.75) caesarean delivery.

CONCLUSION

Maternal obesity is an emerging health problem in Tanzania. This study clearly demonstrates an association between increased risk of intrapartum complications and obesity. A review of guidelines around ANC screening and intrapartum care practices considering BMI, as well as appropriate messages for women with obesity, should be considered to improve maternal and newborn outcomes.

Effect of maternal sleep in late pregnancy on leptin and lipid levels in umbilical cord blood

OBJECTIVES

To study the impact of maternal sleep in late pregnancy on birth weight (BW) and leptin and lipid levels in umbilical cord blood.

STUDY DESIGN

A total of 277 healthy and singleton pregnancy women were recruited for participation in the Shanghai Sleep Birth Cohort Study (SSBC) during their 36-38 weeks of pregnancy, from May 2012 to July 2013. Maternal night sleep time (NST), sleep efficiency (SE), sleep onset latency (SOL) and the percentage of wake after sleep onset (WASO) in NST and midpoint of sleep (MSF) were measured by actigraphy for seven consecutive days. The leptin and lipid levels were determined in cord blood samples collected from the umbilical vein immediately after delivery. Birth information (birth weight, gender, delivery type, etc.) was extracted from medical records. A multivariable linear regression model was applied to examine the effect of maternal sleep in late pregnancy on newborn leptin and lipid levels in umbilical cord blood.

RESULTS

A total of 177 women and their infants were included in the analysis. Maternal mean NST was 7.03 ± 1.10 h in late pregnancy, and 48% had a shorter sleep time (NST < 7 h). The average maternal SE was 72.54% ± 9.66%. The mean percentage WASO/NST was 21.62% ± 9.98%; the average MSF was about 3:34 (0:53); and the SOL was 46.78 ± 36.00 min. After adjustment for confounders, both maternal NST and SE were found to be significantly associated with triglyceride levels (β = -0.219, p = 0.006; β = -0.224, p = 0.006) in umbilical cord blood; and maternal NST was also observed to have positive association with newborn leptin levels (β = 0.146, p = 0.047). However, we did not find significant association between other maternal sleep parameters in late pregnancy and leptin and lipid levels and birth weight.

CONCLUSIONS

Short sleep duration and poor sleep quality during late pregnancy were associated with newborn leptin and lipid levels, and efforts on improving maternal sleep during late pregnancy should be advocated for children's health.

Prevalence of hyperglycemia in pregnancy and influence of body fat on development of hyperglycemia in pregnancy among pregnant women in urban areas of Arusha region, Tanzania

Background

Hyperglycemia in pregnancy is a medical condition resulting from either pre-existing diabetes or insulin resistance developed during pregnancy. This study aimed to determine the prevalence of hyperglycemia in pregnancy and influence of body fat percentage and other determinants on developing hyperglycemia in pregnancy among women in Arusha District, Tanzania.

Methods

A cross–sectional study was conducted between March and December 2018 at selected health facilities in Arusha District involving 468 pregnant women who were not known to have diabetes before pregnancy. Blood glucose was tested by Gluco-Plus™ using the World Health Organization criteria at fasting and 2 h after consuming 75 g of glucose dissolved in 300 ml of water. Body fat was measured using a bioelectric impedance analyzer, mid-upper arm circumference using a regulated tape, weight using SECA™, blood pressure using a GT-868UF Geratherm™ machine, and height using a stadiometer. Demographic and maternal characteristics were collected through face to face interviews using a structured questionnaire.

Results

The participants’ mean age was 28 years (SD ± 6), mid-upper arm circumference 27 cm (SD ± 3.7), body fat 33.72% (SD ± 7.2) and pre-pregnancy body mass index 25.6 kg/m² (SD ± 5.5). One-third of participants had mid-upper arm circumferences ≥28 cm with 25% being overweight and 22.7% obese before pregnancy. Prevalence of hyperglycemia in pregnancy was 16.2% (n = 76) of which 13% had gestational diabetes and 3.2% diabetes in pregnancy. Hyperglycemia in pregnancy was significantly associated with body fat percentage (AOR 1.33; 95% CI: 1.22–1.44), family history of Type 2 diabetes mellitus (AOR 6.95, 95% CI: 3.11–15.55), previous delivery of babies ≥4 kg (AOR 2.3, 95% CI: 1.00–5.28), mid-upper arm circumference ≥ 28 cm (AOR 1.2, 95% CI: 1.09–1.32), and Type 2 diabetes mellitus symptoms (AOR 2.83, 95% CI: 1.53–6.92).

Conclusion

The prevalence of hyperglycemia in pregnancy was high, particularly among women with history of delivering ≥4-kg babies, increased body fat, mid-upper arm circumference, symptoms and/or family history of Type 2 diabetes mellitus. These findings identify opportunities to further explore the utility of body fat percentage and other determinants for rapid screening and management of hyperglycemia in pregnancy.

Impact of maternal body mass index and gestational weight gain on pregnancy complications: an individual participant data meta-analysis of European, North American and Australian cohorts

OBJECTIVE

To assess the separate and combined associations of maternal pre-pregnancy body mass index (BMI) and gestational weight gain with the risks of pregnancy complications and their population impact.

DESIGN

Individual participant data meta-analysis of 39 cohorts.

SETTING

Europe, North America, and Oceania.

POPULATION

265 270 births.

METHODS

Information on maternal pre-pregnancy BMI, gestational weight gain, and pregnancy complications was obtained. Multilevel binary logistic regression models were used.

MAIN OUTCOME MEASURES

Gestational hypertension, pre-eclampsia, gestational diabetes, preterm birth, small and large for gestational age at birth.

RESULTS

Higher maternal pre-pregnancy BMI and gestational weight gain were, across their full ranges, associated with higher risks of gestational hypertensive disorders, gestational diabetes, and large for gestational age at birth. Preterm birth risk was higher at lower and higher BMI and weight gain. Compared with normal weight mothers with medium gestational weight gain, obese mothers with high gestational weight gain had the highest risk of any pregnancy complication (odds ratio 2.51, 95% CI 2.31- 2.74). We estimated that 23.9% of any pregnancy complication was attributable to maternal overweight/obesity and 31.6% of large for gestational age infants was attributable to excessive gestational weight gain.

CONCLUSIONS

Maternal pre-pregnancy BMI and gestational weight gain are, across their full ranges, associated with risks of pregnancy complications. Obese mothers with high gestational weight gain are at the highest risk of pregnancy complications. Promoting a healthy pre-pregnancy BMI and gestational weight gain may reduce the burden of pregnancy complications and ultimately the risk of maternal and neonatal morbidity.

TWEETABLE ABSTRACT

Promoting a healthy body mass index and gestational weight gain might reduce the population burden of pregnancy complications.

The human yolk sac size reflects involvement in embryonic and fetal growth regulation

INTRODUCTION

The human yolk sac provides the embryo with stem cells, nutrients, and gas exchange. We hypothesized that more maternal resources, reflected in body size and body composition, would condition a a larger yolk sac, ensuring resources for the growing embryo. Thus, we aimed to determine the relation between maternal size in early pregnancy and yolk sac size.

MATERIAL AND METHODS

This subsidiary study was embedded in the multinational World Health Organization fetal growth project that included healthy women with a body mass index of 18-30, reliable information of their regular last menstrual period and singleton pregnancies. Yolk sac diameter, crown-rump length, and maternal height, weight, body mass index, and body composition were assessed before 13 weeks of gestation, and the fetal biometry was repeated during the pregnancy.

RESULTS

Of 140 participants, 122 with a successful yolk sac measurement were entered in the present analysis. Maternal weight was negatively associated with the yolk sac diameter (P = 0.007) and so was maternal height (P = 0.011), fat mass (P = 0.037), and lean body mass (P = 0.018), but not body mass index (P = 0.121). Significant effects were predominantly due to the female embryos and could be traced at 24 weeks of gestation. That is, a small yolk sac : crown-rump length ratio in early pregnancy was associated with a high fetal abdominal circumference (P < 0.001) and estimated fetal weight (P = 0.001).

CONCLUSIONS

The human yolk sac is involved in the regulation of embryonic growth, but contrary to our hypothesis, the yolk sac has a compensatory capacity, being larger when the mothers are smaller; and the effect can be traced on fetal size at 24 weeks of gestation.

Do the Low WHRs and BMIs Judged Most Attractive Indicate Higher Fertility?

We examine the widely accepted view that very low waist-hip ratios and low body mass indices (BMIs) in women in well-nourished populations are judged attractive by men because these features reliably indicate superior fertility. In both subsistence and well-nourished populations, relevant studies of fertility do not support this view. Rather studies indicate lower fertility in women with anthropometric values associated with high attractiveness. Moreover, low maternal BMI predisposes to conditions that compromise infant survival. Consistent with these findings from the literature, new data from a large U.S. sample of women past reproductive age show that women with lower BMIs in the late teens had fewer live births, controlling for education, marital history, and race. They also had later menarche and earlier menopause compared with women with higher youth BMIs. In addition, data from the 2013 U.S. natality database show that mothers with lower prepregnancy BMIs have an increased risk of producing both low-birth-weight and preterm infants controlling for other relevant variables-conditions that would have adversely affected fitness over almost all of human evolution. Thus, a review of the relevant literature and three new tests fail to support the view that highly attractive women are more fertile.

Impact of replacing Chinese ethnicity-specific fetal biometry charts with the INTERGROWTH-21(st) standard

OBJECTIVE

To assess the impact of adopting the INTERGROWTH-21(st) biometry standards in a Chinese population.

DESIGN

Retrospective cohort study.

SETTING

A teaching hospital in Hong Kong.

POPULATION

A total of 10 527 Chinese women with a singleton pregnancy having a second- or third-trimester fetal anomaly or growth scan between January 2009 and June 2014.

METHODS

Z-scores were derived for fetal abdominal circumference (AC), head circumference (HC), and femur length (FL) using the INTERGROWTH-21(st) and Chinese biometry standards. Pregnancies with aneuploidy, structural or skeletal abnormalities, or that developed pre-eclampsia were excluded. Z-scores were stratified as <2.5th, <5th, <10th, >90th, >95th, or >97.5th percentile. Birthweight centile, adjusted for gestation and gender, was categorised as ≤3rd, 3rd to ≤5th, 5th to ≤10th, and >10th. Pairwise comparison and the McNemar test were performed to assess biometry Z-score differences and concordance between the INTERGROWTH-21(st) and Chinese standards.

MAIN OUTCOME MEASURES

The sensitivity of both the local and INTERGROWTH-21(st) AC standards to identify pregnancies that were small-for-gestational-age (SGA) was assessed.

RESULTS

INTERGROWTH-21(st) AC, HC, and FL Z-scores were significantly lower than those obtained using our local reference for AC, HC, and FL (P < 0.0001 for all). The proportion of fetuses with biometry in the <2.5th, <5th, <10th, >90th, >95th, or >97.5th percentiles was statistically significant (P < 0.01 for all). A total of 1224 (15.5%) of the scans at 18-22 weeks of gestation had AC, HC, or FL below the 3rd percentile of the INTERGROWTH-21(st) standard.

CONCLUSIONS

Adopting the INTERGROWTH-21(st) standard would lead to a significant number of fetuses being at risk of misdiagnosis for small fetal size, particularly when using HC and FL measures.

TWEETABLE ABSTRACT

INTERGROWTH-21(st) biometry assessment in Chinese leads to fetuses being at risk of misdiagnosis of small fetal size.

A new customized fetal growth standard for African American women: the PRB/NICHD Detroit study

BACKGROUND

The assessment of fetal growth disorders requires a standard. Current nomograms for the assessment of fetal growth in African American women have been derived either from neonatal (rather than fetal) biometry data or have not been customized for maternal ethnicity, weight, height, and parity and fetal sex.

OBJECTIVE

We sought to (1) develop a new customized fetal growth standard for African American mothers; and (2) compare such a standard to 3 existing standards for the classification of fetuses as small (SGA) or large (LGA) for gestational age.

STUDY DESIGN

A retrospective cohort study included 4183 women (4001 African American and 182 Caucasian) from the Detroit metropolitan area who underwent ultrasound examinations between 14-40 weeks of gestation (the median number of scans per pregnancy was 5, interquartile range 3-7) and for whom relevant covariate data were available. Longitudinal quantile regression was used to build models defining the "normal" estimated fetal weight (EFW) centiles for gestational age in African American women, adjusted for maternal height, weight, and parity and fetal sex, and excluding pathologic factors with a significant effect on fetal weight. The resulting Perinatology Research Branch/Eunice Kennedy Shriver National Institute of Child Health and Human Development (hereinafter, PRB/NICHD) growth standard was compared to 3 other existing standards--the customized gestation-related optimal weight (GROW) standard; the Eunice Kennedy Shriver National Institute of Child Health and Human Development (hereinafter, NICHD) African American standard; and the multinational World Health Organization (WHO) standard--utilized to screen fetuses for SGA (<10th centile) or LGA (>90th centile) based on the last available ultrasound examination for each pregnancy.

RESULTS

First, the mean birthweight at 40 weeks was 133 g higher for neonates born to Caucasian than to African American mothers and 150 g higher for male than female neonates; maternal weight, height, and parity had a positive effect on birthweight. Second, analysis of longitudinal EFW revealed the following features of fetal growth: (1) all weight centiles were about 2% higher for male than for female fetuses; (2) maternal height had a positive effect on EFW, with larger fetuses being affected more (2% increase in the 95th centile of weight for each 10-cm increase in height); and (3) maternal weight and parity had a positive effect on EFW that increased with gestation and varied among the weight centiles. Third, the screen-positive rate for SGA was 7.2% for the NICHD African American standard, 12.3% for the GROW standard, 13% for the WHO standard customized by fetal sex, and 14.4% for the PRB/NICHD customized standard. For all standards, the screen-positive rate for SGA was at least 2-fold higher among fetuses delivered preterm than at term. Fourth, the screen-positive rate for LGA was 8.7% for the GROW standard, 9.2% for the PRB/NICHD customized standard, 10.8% for the WHO standard customized by fetal sex, and 12.3% for the NICHD African American standard. Finally, the highest overall agreement among standards was between the GROW and PRB/NICHD customized standards (Cohen's interrater agreement, kappa = 0.85).

CONCLUSION

We developed a novel customized PRB/NICHD fetal growth standard from fetal data in an African American population without assuming proportionality of the effects of covariates, and without assuming that these effects are equal on all centiles of weight; we also provide an easy-to-use centile calculator. This standard classified more fetuses as being at risk for SGA compared to existing standards, especially among fetuses delivered preterm, but classified about the same number of LGA. The comparison among the 4 growth standards also revealed that the most important factor determining agreement among standards is whether they account for the same factors known to affect fetal growth.

Association of Maternal Obesity With Longitudinal Ultrasonographic Measures of Fetal Growth: Findings From the NICHD Fetal Growth Studies-Singletons

IMPORTANCE

Despite the increasing prevalence of pregravid obesity, systematic evaluation of the association of maternal obesity with fetal growth trajectories is lacking.

OBJECTIVE

To characterize differences in fetal growth trajectories between obese and nonobese pregnant women, and to identify the timing of any observed differences.

DESIGN, SETTING, AND PARTICIPANTS

The Eunice Kennedy Shriver National Institute of Child Health and Human Development Fetal Growth Studies-Singletons study enrolled cohorts of pregnant women at 12 US health care institutions. Obese women (with prepregnancy body mass index > 30) and nonobese women (prepregnancy body mass indexes, 19-29.9) without major chronic diseases were recruited between 8 weeks and 0 days' gestation and 13 weeks and 6 days' gestation. A mixed longitudinal randomization scheme randomized participants into 1 of 4 schedules for 2-dimensional and 3-dimensional ultrasonograms to capture weekly fetal growth data throughout the remainder of their pregnancies.

MAIN OUTCOMES AND MEASURES

On each ultrasonogram, fetal humerus length, femur length, biparietal diameter, head circumference, and abdominal circumference were measured. Fetal growth curves were estimated using linear mixed models with cubic splines. Median differences in the fetal measures at each gestational week of the obese and nonobese participants were examined using the likelihood ratio and Wald tests after adjustment for maternal characteristics.

RESULTS

The study enrolled 468 obese and 2334 nonobese women between 8 weeks and 0 days' gestation and 13 weeks and 6 days' gestation. After a priori exclusion criteria, 443 obese and 2320 nonobese women composed the final cohort. Commencing at 21 weeks' gestation, femur length and humerus length were significantly longer for fetuses of obese woman than those of nonobese women. Differences persisted in obese and nonobese groups through 38 weeks' gestation (median femur length, 71.0 vs 70.2 mm; P = .01; median humerus length, 62.2 vs 61.6 mm; P = .03). Averaged across gestation, head circumference was significantly larger in fetuses of obese women than those of nonobese women (P = .02). Fetal abdominal circumference was not greater in the obese cohort than in the nonobese cohort but was significantly larger than in fetuses of normal-weight women (with body mass indexes between 19.0-24.9) commencing at 32 weeks (median, 282.1 vs 280.2 mm; P = .04). Starting from 30 weeks' gestation, estimated fetal weight was significantly larger for the fetuses of obese women (median, 1512 g [95% CI, 1494-1530 g] vs 1492 g [95% CI, 1484-1499 g]) and the difference grew as gestational age increased. Birth weight was higher by almost 100 g in neonates born to obese women than to nonobese women (mean, 3373.2 vs 3279.5 g).

CONCLUSIONS AND RELEVANCE

As early as 32 weeks' gestation, fetuses of obese women had higher weights than fetuses of nonobese women. The mechanisms and long-term health implications of these findings are not yet established.

A novel body mass index reference range - an observational study

OBJECTIVE

To generate a new body mass index curve of reference values and ranges for body mass index and weight gain during pregnancy and to compare the new curve and weight gain ranges with the currently used references.

METHODS

A prospective observational study was conducted with a total of 5,656 weight and body mass index measurements in 641 women with single pregnancy who attended their first prenatal visit before 12 weeks. All the women were over 18 years old and had no medical conditions that would influence body mass index. Data were collected using prenatal charts and medical records during hospitalization for childbirth. A linear regression method was used for standard curve smoothing in the general population and for specific curves according to the baseline body mass index classification. Curves were obtained for the 5th, 10th, 50th, 85th, 90th and 95th percentiles. Concordance between the classification of women using the newly generated and currently used curves was evaluated by percentages and kappa coefficients. The weight gain was compared with the reference values of the Institute of Medicine using Student's T test. The data were analyzed using SAS software version 9.2, and the significance level was set at 5%.

RESULTS

A general reference curve of percentiles of body mass index by gestational age was established. Additionally, four specific curves were generated according to the four baseline body mass index categories. The new general curve offered percentile limits for women according to their initial body mass index and according to the Centers for Disease Control and Prevention limits, showing poor agreement with the currently used curve (48.3%). Women who were overweight or obese when starting prenatal care had higher weight gain than the Institute of Medicine recommendation.

CONCLUSIONS

The new proposed curve for body mass index during pregnancy showed weak agreement with the currently used curve. The new curve provided more information regarding body mass index increase using percentiles for general and specific groups of body mass index. Overweight pregnant women showed an upward body mass index trend throughout pregnancy that increased more dramatically than those of other groups of pregnant women, and they also presented a major mean difference between weight gain and the Institute of Medicine recommendation.

Composite neonatal and maternal morbidities with small- versus appropriate- for gestational age among uncomplicated obese women undergoing repeat cesarean delivery. J Matern Fetal Neonatal Med 2017;32:562-567. [PMID: 28942717 DOI: 10.1080/14767058.2017.1384808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

PURPOSE

Our goal was to compare composite neonatal and maternal morbidities (composite neonatal morbidity (CNM), composite maternal morbidity (CMM)) among deliveries with small for age (SGA) versus appropriate for gestational age (AGA; birthweight 10-89%) among obese versus non-obese women undergoing repeat cesarean delivery (CD).

STUDY DESIGN

This is a secondary analysis of a prospective observational study. Women who had elective CD ≥37 weeks were studied. We excluded multiple gestations, fetal anomalies, > 1 prior CD, and medical diseases. Patients were divided into BMI ≥30 versus <30 kg/m². CNM included respiratory distress syndrome, necrotizing enterocolitis, severe intraventricular hemorrhage, seizure, or death; CMM included transfusion, hysterectomy, operative injury, coagulopathy, thromboembolism, pulmonary edema, or death. Multivariate logistic regression was used to control for confounding factors.

RESULTS

Of 7561 women, we included 65% were obese and 35% were not. SGA rates differed significantly: 8 versus 12% (p < .001). Overall, CNM was significantly higher in patients with SGA versus AGA (adjusted odds ratio (aOR) 2.04, 95% CI 1.19-3.49). CMM of SGA in obese versus non-obese was statistically different (aOR 0.11, 95% CI 0.02-0.68). Among obese mothers, SGA neonates had significantly higher CNM compared with AGA ones (aOR 2.17, 95% CI 1.03-4.59).

CONCLUSIONS

SGA occurred in 8% of low-risk obese women with prior CD. CNM of SGA babies in obese versus non-obese women were similar. Paradoxically, CMM was lower in obese cases, possibly reflecting the caution that obese patients receive preoperatively. Our findings may assist in counseling patients and designing trials.

Titration of Intravenous Oxytocin Infusion for Postdates Induction of Labor Across Body Mass Index Groups

OBJECTIVE

To evaluate whether oxytocin titration for postdates labor induction differs among women who are normal weight, overweight, and obese and whether length of labor and birth method differ by oxytocin titration and body mass index (BMI).

DESIGN

Retrospective cohort study.

SETTING

U.S. university-affiliated hospital.

PARTICIPANTS

Of 280 eligible women, 21 were normal weight, 134 were overweight, and 125 were obese at labor admission.

METHODS

Data on women who received oxytocin for postdates induction between January 1, 2013 and June 30, 2013 were extracted from medical records. Oxytocin administration and labor outcomes were compared across BMI groups, controlling for potential confounders. Data were analyzed using χ², analysis of variance, analysis of covariance, and multiple linear and logistic regression models.

RESULTS

Women who were obese received more oxytocin than women who were overweight in the unadjusted analysis of variance (7.50 units compared with 5.92 units, p = .031). Women who were overweight had more minutes between rate changes from initiation to maximum than women who were obese (98.19 minutes compared with 83.39 minutes, p = .038). Length of labor increased with BMI (p = .018), with a mean length of labor for the normal weight group of 13.96 hours (standard deviation = 8.10); for the overweight group, 16.00 hours (standard deviation = 7.54); and for the obese group, 18.30 hours (standard deviation = 8.65). Cesarean rate increased with BMI (p = .001), with 4.8% of normal weight, 33.6% of overweight, and 42.4% of obese women having cesarean births.

CONCLUSION

Women who were obese and experienced postdates labor induction received more oxytocin than women who were non-obese and had longer length of labor and greater cesarean rates.

Timing of Gestational Weight Gain on Fetal Growth and Infant Size at Birth in Vietnam

OBJECTIVE

To examine the importance of timing of gestational weight gain during three time periods: 1: ≤ 20 weeks gestation), 2: 21-29 weeks) and 3: ≥ 30 weeks) on fetal growth and infant birth size.

METHODS

Study uses secondary data from the PRECONCEPT randomized controlled trial in Thai Nguyen province, Vietnam (n = 1436). Prospective data were collected on women starting pre-pregnancy through delivery. Maternal conditional weight gain (CWG) was defined as window-specific weight gains, uncorrelated with pre-pregnancy body mass index and all prior body weights. Fetal biometry, was assessed by ultrasound measurements of head and abdomen circumferences, biparietal diameter, and femoral length throughout pregnancy. Birth size outcomes included weight and length, and head, abdomen and mid upper arm circumferences as well as small for gestational age (SGA). Adjusted generalized linear and logistic models were used to examine associations.

RESULTS

Overall, three-quarters of women gained below the Institute of Medicine guidelines, and these women were 2.5 times more likely to give birth to a SGA infant. Maternal CWG in the first window (≤ 20 weeks), followed by 21-29 weeks, had the greatest association on all parameters of fetal growth (except abdomen circumference) and infant size at birth. For birth weight, a 1 SD increase CWG in the first 20 weeks had 3 times the influence compared to later CWG (≥ 30 weeks) (111 g vs. 39 g) and was associated with a 43% reduction in SGA risk (OR (95% CI): 0.57 (0.46-0.70).

CONCLUSION

There is a need to target women before or early in pregnancy to ensure adequate nutrition to maximize impact on fetal growth and birth size.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01665378.

How maternal malnutrition affects linear growth and development in the offspring

Maternal malnutrition is common in the developing world and has detrimental effects on both the mother and infant. Pre-pregnancy nutritional status and weight gain during pregnancy are positively related to fetal growth and development. Internationally, there is no agreement on the method of diagnosis or treatment of moderate or severe malnutrition during pregnancy. Establishing clear guidelines for diagnosis and treatment will be essential in elevating the problem. Possible anthropometric measurements used to detect and monitor maternal malnutrition include pre-pregnancy BMI, weight gain, and mid upper arm circumference. Food supplements have the potential to increase gestational weight gain and energy intake which are positively associated with fetal growth and development. Overall more studies are needed to conclude the impact of food/nutrient supplements on infant growth in undernourished pregnant women in developing countries. Currently, a study underway may provide much needed documentation of the benefits of treating malnutrition in pregnancy.

MATERNAL HEIGHT AND PRE-PREGNANCY WEIGHT STATUS ARE ASSOCIATED WITH FETAL GROWTH PATTERNS AND NEWBORN SIZE

The impact of maternal height, pre-pregnancy weight status and gestational weight gain on fetal growth patterns and newborn size was analysed using a dataset of 4261 singleton term births taking place at the Viennese Danube Hospital between 2005 and 2013. Fetal growth patterns were reconstructed from three ultrasound examinations carried out at the 11th/12th, 20th/21th and 32th/33th weeks of gestation. Crown–rump length, biparietal diameter, fronto-occipital diameter, head circumference, abdominal transverse diameter, abdominal anterior–posterior diameter, abdominal circumference and femur length were determined. Birth weight, birth length and head circumference were measured immediately after birth. The vast majority of newborns were of normal weight, i.e. between 2500 and 4000 g. Maternal height showed a just-significant but weak positive association (r=0.03: p=0.039) with crown–rump length at the first trimester and with the majority of fetal parameters at the second trimester (r>0.06; p<0.001) and third trimester (r>0.09; p<0.001). Pre-pregnancy weight status was significantly positively associated with nearly all fetal dimensions at the third trimester (r>0.08; p<0.001). Maternal height (r>0.17; p<0.001) and pre-pregnancy weight status (r>0.13; p<0.001), but also gestational weight gain (r>0.13; p<0.001), were significantly positively associated with newborn size. Some of these associations were quite weak and the statistical significance was mainly due to the large sample size. The association patterns between maternal height and pre-pregnancy weight status with fetal growth patterns (p<0.001), as well as newborn size (p<0.001), were independent of maternal age, nicotine consumption and fetal sex. In general, taller and heavier women gave birth to larger infants. This association between maternal size and fetal growth patterns was detectable from the first trimester onwards.

Antenatal dietary and lifestyle advice for women who are overweight or obese and the effect on fetal growth and adiposity: the LIMIT randomised trial

OBJECTIVE

To report the influence of maternal overweight and obesity on fetal growth and adiposity and effects of an antenatal dietary and lifestyle intervention among these women on measures of fetal growth and adiposity as secondary outcomes of the LIMIT Trial.

DESIGN

Randomised controlled trial.

SETTING

Public maternity hospitals in metropolitan Adelaide, South Australia.

POPULATION

Pregnant women with a body mass index ≥ 25 kg/m(2), and singleton gestation between 10(+0) and 20(+0) weeks.

METHODS

Women were randomised to Lifestyle Advice or continued Standard Care and offered two research ultrasound scans at 28 and 36 weeks of gestation.

MAIN OUTCOME MEASURES

Ultrasound measures of fetal growth and adiposity.

RESULTS

For each fetal body composition parameter, mean Z-scores were substantially higher when compared with population standards. Fetuses of women receiving Lifestyle Advice demonstrated significantly greater mean mid-thigh fat mass, when compared with fetuses of women receiving Standard Care (adjusted difference in means 0.17; 95% CI 0.02-0.32; P = 0.0245). While subscapular fat mass increased between 28 and 36 weeks of gestation in fetuses in both treatment groups, the rate of adipose tissue deposition slowed among fetuses of women receiving Lifestyle Advice, when compared with fetuses of women receiving Standard Care (P = 0.0160). No other significant differences were observed.

CONCLUSIONS

These findings provide the first evidence of changes to fetal growth following an antenatal dietary and lifestyle intervention among women who are overweight or obese.

Maternal clinic and home blood pressure measurements during pregnancy and infant birth weight: the BOSHI study

This prospective cohort study compared measurements of maternal home blood pressure (HBP) with clinic blood pressure (CBP) before 20 weeks' gestation to determine associations with the risk of delivering a lower birth weight infant. A total of 605 Japanese women were included. Exposures were initial CBP, made between 10 weeks 0 days and 19 weeks 0 days, and HBP for comparison made within 1 week of CBP. Outcome was infant's birth weight, categorized and ranked as follows: ⩾3500 g, 3000-3499 g, 2500-2999 g and <2500 g. The proportional odds model with possible confounding factors was applied to compare the associations between CBP and HBP on infant birth weight. When both CBP and HBP were included simultaneously, the adjusted odds ratios (ORs) per 1 standard deviation (1s.d.) increase in clinic and home diastolic BP (DBP) were 1.06 (95% confidence interval (CI): 0.87-1.30) and 1.28 (95% CI: 1.04-1.58), respectively. The adjusted ORs per 1s.d. increase in clinic and home mean arterial pressure (MAP) were 1.02 (95% CI: 0.83-1.24) and 1.29 (95% CI: 1.04-1.59), respectively. Systolic BP measurement was not associated with infant birth weight. In conclusion, high maternal home DBP and MAP before 20 weeks' gestation was associated with a higher risk of lower infant birth weight than clinic DBP and MAP. Therefore, in addition to CBP, it may be worth having pregnant women measure HBP to determine the risk of lower infant birth weight.

Sonographic fetal weight estimation in normal and overweight/obese healthy term pregnant women by gestation-adjusted projection (GAP) method

PURPOSE

The objective of this study is to assess the ultrasound accuracy in fetal weight estimation related to the time distance between the actual weight recorded at delivery and the period of sonography among normal and overweight/obese pregnant women within 3 weeks prior birth at term.

METHODS

Four-hundred and ninety patients with healthy pregnancy were studied in a cohort study. The absolute percent error in estimation was achieved by gestation-adjusted projection method from Hadlock model for weight calculation as measure of accuracy. The mean percentage error variation over the weeks was correlated to maternal body mass index (BMI, Kg/m(2)) at ultrasound. The relationship between BMI and ultrasound performance was assessed by linear regression.

RESULTS

The overall proportion of supposed sonographic estimated fetal weight at birth within ±10 % of the birth weight significantly declines over the weeks (P = .016). The trend toward a progressive deterioration in ultrasound accuracy is not statistically significant for normal weight women (P = .272) but it is for over-weight/obese (P = .044). On univariate analysis, the absolute percent error and absolute error are positively related to BMI.

CONCLUSIONS

Accuracy is related to the week at ultrasound scan with a gradual deterioration over the time and it worsens with increasing distance in days between the date of ultrasounds and delivery. The deterioration is greater for BMI ≥ 25.

Ethnic Differences in Effects of Maternal Pre-Pregnancy and Pregnancy Adiposity on Offspring Size and Adiposity

CONTEXT

Maternal adiposity and overnutrition, both before and during pregnancy, plays a key role in the subsequent development of obesity and metabolic outcomes in offspring.

OBJECTIVE

We explored the hypothesis that maternal adiposity (pre-pregnancy and at 26-28 weeks' gestation) and mid-pregnancy gestational weight gain (GWG) are independently associated with offspring size and adiposity in early childhood, and determined whether these effects are ethnicity dependent.

DESIGN

In a prospective mother-offspring cohort study (N = 976, 56% Chinese, 26% Malay, and 18% Indian), we assessed the associations of offspring size (weight, length) and adiposity (subscapular and triceps skinfolds), measured at birth and age 6, 12, 18, and 24 mo, with maternal pre-pregnancy body mass index (ppBMI), mid-pregnancy GWG, and mid-pregnancy four-site skinfold thicknesses (triceps, biceps, subscapular, suprailiac).

RESULTS

ppBMI and mid-pregnancy GWG were independently associated with postnatal weight up to 2 y and skinfold thickness at birth. Weight and subscapular and triceps skinfolds at birth increased by 2.56% (95% confidence interval, 1.68-3.45%), 3.85% (2.16-5.57%), and 2.14% (0.54-3.75%), respectively for every SD increase in ppBMI. Similarly, a one-SD increase in GWG increased weight and subscapular and triceps skinfolds at birth by 2.44% (1.66-3.23%), 3.28% (1.75-4.84%), and 3.23% (1.65-4.84%), respectively. ppBMI and mid-pregnancy suprailiac skinfold independently predicted postnatal skinfold adiposity up to 2 years of age, whereas only GWG predicted postnatal length. The associations of GWG with postnatal weight and length were present only among Chinese and Indians, but not Malays (P < .05 for interaction).

CONCLUSIONS

ppBMI and GWG are independent modifiable factors for child size and adiposity up to 2 years of age. The associations are ethnic-dependent, and underscore the importance of ethnic specific studies before generalizing the applicability of risk factors reported in other populations.

Maternal obesity during pregnancy and cardiovascular development and disease in the offspring

Maternal obesity during pregnancy is an important public health problem in Western countries. Currently, obesity prevalence rates in pregnant women are estimated to be as high as 30 %. In addition, approximately 40 % of women gain an excessive amount of weight during pregnancy in Western countries. An accumulating body of evidence suggests a long-term impact of maternal obesity and excessive weight gain during pregnancy on adiposity, cardiovascular and metabolic related health outcomes in the offspring in fetal life, childhood and adulthood. In this review, we discuss results from recent studies, potential underlying mechanisms and challenges for future epidemiological studies.

Ethnic disparities in maternal obesity and weight gain during pregnancy. The Generation R Study

Objective

To examine ethnic disparities in maternal prepregnancy obesity and gestational weight gain, and to examine to which extent these differences can be explained by socio-demographic, lifestyle and pregnancy related characteristics.

Methods

In a multi-ethnic population-based prospective cohort study among 6,444 pregnant women in Rotterdam, the Netherlands, maternal anthropometrics were repeatedly measured throughout pregnancy. Ethnicity, socio-demographic, lifestyle and pregnancy related characteristics were assessed by physical examinations and questionnaires.

Results

The prevalence of prepregnancy overweight and obesity was 23.1% among Dutch-origin women. Statistically higher prevalences were observed among Dutch Antillean-origin (40.8%), Moroccan-origin (49.9%), Surinamese-Creole-origin (38.6%) and Turkish-origin (41.1%) women (all p-values <0.05). Only Dutch Antillean-origin, Moroccan-origin, Surinamese-Creole-origin and Turkish-origin women had higher risks of maternal prepregnancy overweight and obesity as compared to Dutch-origin women (p-values <0.05). Socio-demographic and lifestyle related characteristics explained up to 45% of the ethnic differences in body mass index. Compared to Dutch-origin women, total gestational weight gain was lower in all ethnic minority groups, except for Cape Verdean-origin and Surinamese-Creole-origin women (p-values <0.05). Lifestyle and pregnancy related characteristics explained up to 33% and 40% of these associations, respectively. The largest ethnic differences in gestational weight gain were observed in late pregnancy.

Conclusion

We observed moderate ethnic differences in maternal prepregnancy overweight, obesity and gestational weight gain. Socio-demographic, lifestyle and pregnancy related characteristics partly explained these differences. Whether these differences also lead to ethnic differences in maternal and childhood outcomes should be further studied.

Assessment of fetal growth by customized growth charts

Customized fetal growth charts take account of the individual variation in the fetal growth potential based on non-pathological maternal and fetal characteristics. Application of these customized weight charts might improve the distinction between pathological growth-restricted fetuses and fetuses that are small but have reached their growth potential. Current models for customized growth standards have been based on birth weight and fetal growth data. Variables used for customization are gestational age, maternal age, parity, ethnicity, height, weight and fetal sex. Thus far, it remains controversial whether these maternal and fetal characteristics used for customization are strong enough predictors for fetal growth on an individual level and are truly physiological characteristics. The currently available customized growth charts might be of benefit for use in epidemiological studies and clinical practice. Further studies are needed to validate these customized growth models and to examine whether and to what extend they improve identification of children that are at risk for morbidity in the perinatal period and later in life.

Childhood consequences of maternal obesity and excessive weight gain during pregnancy

Obesity is a major public health concern. In western countries, the prevalence of obesity in pregnant women has strongly increased, with reported prevalence rates reaching 30%. Also, up to 40% of women gain an excessive amount of weight during pregnancy. Recent observational studies and meta-analyses strongly suggest long-term impact of maternal obesity and excessive weight gain during pregnancy on adiposity, cardiovascular and respiratory related health outcomes in their children. These observations suggest that maternal adiposity during pregnancy may program common health problems in the offspring. Currently, it remains unclear whether the observed associations are causal, or just reflect confounding by family-based sociodemographic or lifestyle-related factors. Parent-offspring studies, sibling comparison studies, Mendelian randomization studies and randomized trials can help to explore the causality and underlying mechanisms. Also, the potential for prevention of common diseases in future generations by reducing maternal obesity and excessive weight gain during pregnancy needs to be explored.

Maternal weight gain in different periods of pregnancy and childhood cardio-metabolic outcomes. The Generation R Study

BACKGROUND

Excessive gestational weight gain seems to be associated with offspring cardio-metabolic risk factors. Little is known about the critical periods of gestational weight gain. We examined the associations of maternal weight gain in different periods of pregnancy with childhood cardio-metabolic risk factors.

METHODS

In a population-based prospective cohort study from early pregnancy onwards among 5908 mothers and their children, we obtained maternal prepregnancy weight and weight in early, mid and late pregnancy. At the age of 6 years (median: 72.6 months; 95% range: 67.9, 95.8), we measured childhood body mass index (BMI), total body and abdominal fat distribution, blood pressure and blood levels of lipids, insulin and c-peptide.

RESULTS

Overall, the associations of maternal prepregnancy weight with childhood outcomes were stronger than the associations of maternal gestational weight gain. Independent from maternal prepregnancy weight and weight gain in other periods, higher weight gain in early pregnancy was associated with higher childhood BMI, total fat mass, android/gynoid fat mass ratio, abdominal subcutaneous fat mass and systolic blood pressure (P-values<0.05). Independent associations of maternal weight gain in early pregnancy with childhood abdominal preperitoneal fat mass, insulin and c-peptide were of borderline significance. Higher weight gain in mid pregnancy was independently associated with higher childhood BMI, total and abdominal subcutaneous fat mass and systolic blood pressure (P-values<0.05). The associations for childhood cardio-metabolic outcomes attenuated after adjustment for childhood BMI. Weight gain in late pregnancy was not associated with childhood outcomes. Higher weight gain in early, but not in mid or late pregnancy, was associated with increased risks of childhood overweight and clustering of cardio-metabolic risk factors (odds ratio (OR) 1.19 (95% confidence interval (CI): 1.10, 1.29) and OR 1.20 (95% CI: 1.07, 1.35) per standard deviation increase in early gestational weight gain, respectively).

CONCLUSIONS

Higher weight gain in early pregnancy is associated with an adverse cardio-metabolic profile in offspring. This association is largely mediated by childhood adiposity.

Antenatal predictors and body composition of large-for-gestational-age newborns: perinatal health outcomes

OBJECTIVE

To compare body composition of large-for-gestational-age (LGA) with appropriate-for-gestational-age (AGA) newborns and to identify antenatal predictors of LGA.

STUDY DESIGN

This cross-sectional study included 536 term, singleton infants. Anthropometric measurements were performed within 48 h of birth and included determination of body fat percentage (%BF) by air displacement plethysmography. Associations were investigated using logistic regression.

RESULT

LGA infants had greater %BF (P<0.001) compared with AGA infants. Significant predictors of LGA infants included parity (odds ratio (OR)=1.98, (95% confidence interval (CI) 1.00, 4.02)), paternal height (OR=1.08, (95% CI 1.03, 1.14)), maternal pregravid weight (65 to 74.9 kg: OR=2.77, (95% CI 1.14, 7.06)) and gestational weight gain (OR=1.09, 95% CI (1.03, 1.16)). Gestational diabetes mellitus was not associated with LGA infants (P=0.598).

CONCLUSION

Paternal height, parity, maternal pregravid weight and gestational weight gain were strongly associated with LGA infants. These results may allow early prediction and potential modification, thereby optimising clinical outcomes.

Fetal sex and race modify the predictors of fetal growth

The objective of this study is unknown if fetal sex and race modify the impact of maternal pre-pregnancy body mass index (BMI), and smoking on fetal growth. The authors studied markers of fetal growth in singleton offspring of 8,801 primiparous, normotensive women, enrolled in the Collaborative Perinatal Project. The authors tested for departures from additivity between sex/race and each predictor. The head-to-chest circumference ratio (HCC) decreased more, while birthweight and ponderal index (PI) increased more for each 1 kg/m(2) increase in pre-pregnancy BMI among term females versus males (P = 0.07, P < 0.01 and P = 0.08, interaction respectively). For term offspring of White compared with Black women, smoking independent of "dose" was associated with larger reductions in growth (165 g vs. 68 g reduction in birthweight, P < 0.01, interaction), greater reduction in fetal placental ratio (P < 0.01, interaction), PI (P < 0.01, interaction), and greater increase in HCC (P = 0.02), respectively. The association of BMI and smoking with fetal size appeared to be reversed in term versus preterm infants. Our study provides evidence that the associations of pre-pregnancy BMI and smoking are not constant across sex and race. This finding may be relevant to sex and race differences in neonatal and long term health outcomes.

Implications of High Free Thyroxine (FT4) concentrations in euthyroid pregnancies: the FaSTER trial

CONTEXT

Lower birth weight has been reported in conjunction with high maternal free T4 (FT4) in euthyroid pregnancies, raising concerns for suboptimal outcomes.

OBJECTIVE

The objective of the study was to explore the relationships between high maternal FT4 and pregnancy complications in euthyroid women and to further examine the relationships among maternal size, FT4, and birth weight.

DESIGN

This was an observational multicenter cohort study.

SETTING

The study was conducted at prenatal clinics.

STUDY SUBJECTS

A total of 9209 euthyroid women with singleton pregnancies participated in the study.

INTERVENTIONS

There were no interventions.

MAIN OUTCOME MEASURES

Relationships between second-trimester high maternal FT4 and pregnancy/delivery complications and, among FT4, maternal weight and birth weight were measured.

RESULTS

Women in the highest FT4 quintile are younger and weigh less than women in quintiles 1-4; gestational diabetes and preeclampsia occur less often (P = < .001, P < .001, P < .001, and P = .05, respectively). Lowest median birth weight occurs among women in the highest FT4 quintile (P = < .001), but deliveries less than 37 weeks' gestation are not increased. Labor/delivery complications do not differ by FT4 quintile. Restricting analyses to maternal weight-adjusted small-for-gestational-age deliveries yields similar results, except for preeclampsia. In the highest maternal weight decile, adjusted median birth weight is 266 g higher (8.3%) than in the lowest weight decile; adjusted median FT4 is 0.91 pmol/L lower (6.8%). Among women in the highest FT4 decile, adjusted median birth weight is 46 g lower (1.3%) than in the lowest FT4 decile. All three relationships are statistically significant (P < .001, P < .001, and P = .004, respectively).

CONCLUSIONS

Lower median birth weight among euthyroid women with high FT4 is not associated with adverse pregnancy outcomes. Further investigation is indicated to determine how the variations in thyroid hormone concentration influence birth weight.

Challenges in determining body fat in pregnant women

BACKGROUND/AIMS

Determining body composition in pregnant women is challenging as not all of the existing applicable methodologies can be used during pregnancy and not all of the methods have been properly standardized. The aim of this study was to compare the existing anthropometric methods for the evaluation of body composition, especially in pregnant women.

METHODS

One hundred forty-seven pregnant volunteers aged [average (SD)] 31 years (± 4) in gestational week 32 (± 3) provided information on their age and prepregnancy body mass. Their height, current mass, skinfold thicknesses, and limb circumferences were measured. The body density and fat percentage were calculated according to 17 different anthropometric equations obtained from the literature. Data were analyzed with ANOVA.

RESULTS

For the same sample of pregnant women, the body fat percentages obtained using the existing anthropometric methods varied greatly (p < 0.0001) and ranged from 16% (± 5) to 38% (± 4); methods developed specifically for pregnant women yielded disturbingly large differences, with body fat values ranging from 16% (± 5) to 36% (± 6).

CONCLUSIONS

This study revealed large discrepancies among anthropometric methods for body composition assessment in pregnant women. As the results from the same sample obtained with different existing equations are wide ranging, the existing methodologies should be examined and improved before they can serve as sources of information regarding the health status of pregnant women.

Tracking of fetal growth characteristics during different trimesters and the risks of adverse birth outcomes

BACKGROUND

Fetal growth characteristics are used to identify influences of several maternal characteristics and to identify individuals at increased risk of adverse outcomes. The extent to which fetal growth characteristics track in different trimesters is not known.

METHODS

In a population-based prospective cohort study among 8636 pregnant women, we examined the extent to which fetal growth characteristics track, are influenced by maternal socio-demographic and lifestyle related determinants and are associated with birth outcomes. Fetal growth was assessed in each trimester and at birth.

RESULTS

Correlation coefficient between first-trimester crown-rump length and birthweight was r = 0.12 (P-value < 0.05). Correlation coefficients for fetal-head circumference, (femur) length and (estimated) fetal weight ranged from r = 0.16 to r = 0.30 (all P-values < 0.05) between second trimester and birth and from r = 0.36 to r = 0.58 (all P-values < 0.05) between third trimester and birth, and were highest for (estimated) fetal weight. Correlation coefficients for (estimated) fetal weight tended to be lower among overweight mothers, as compared with normal weight mothers, but were not influenced by other maternal characteristics. First, second and third-trimester fetal growth characteristics were associated with risks of preterm birth and small size for gestational age at birth,with the strongest associations present in third trimester.

CONCLUSION

Fetal growth characteristics track moderately throughout gestation, with stronger tracking coefficients present in later pregnancy. Tracking coefficients were not materially influenced by maternal socio-demographic and lifestyle characteristics. First, second and third trimester fetal growth characteristics were associated with the risk of adverse birth outcomes.