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.

Influence of fetal blood flow redistribution on fetal and childhood growth and fat distribution: the Generation R Study

OBJECTIVE

A suboptimal intrauterine environment leads to fetal blood flow redistribution and fetal growth restriction. Not much is known about childhood growth consequences. We examined the associations of fetal blood flow redistribution with birth outcomes, and repeatedly measured fetal and childhood growth and fat mass measures.

DESIGN

Prospective cohort study.

SETTING

Population-based.

POPULATION

One thousand one hundred and ninety-five pregnant women and their children.

METHODS

We measured umbilical and cerebral artery blood flow at a gestational age of 30.3 weeks (95% range, 28.5-32.6 weeks). A higher umbilical/cerebral (U/C) pulsatility index ratio is an indicator of preferential blood flow to the brain cerebral circulation at the expense of the lower body parts.

MAIN OUTCOME MEASURES

Fetal and childhood growth were repeatedly measured from the third trimester until childhood. We measured the total body fat mass, lean fat mass and android/gynoid fat mass ratio by dual-energy X-ray absorptiometry and preperitoneal fat by ultrasound at 6 years.

RESULTS

A higher fetal U/C ratio was associated with increased risks of preterm birth and small size for gestational age at birth [odds ratios, 1.41 (95% confidence interval, 1.08-1.85) and 1.63 (95% confidence interval, 1.21-2.19), respectively, per SDS increase in U/C ratio]. Longitudinal growth analyses showed that a higher fetal U/C ratio was associated with persistently lower head circumference, length and weight from third trimester fetal life until childhood (all P < 0.05). The fetal U/C ratio was not associated with total body and abdominal fat measures at 6 years.

CONCLUSION

Our results suggest that fetal blood flow redistribution affects fetal development and has persistent consequences for childhood growth.

TWEETABLE ABSTRACT

Fetal blood flow redistribution affects fetal development and has persistent consequences for childhood growth.

Fetal sex dependency of maternal vascular adaptation to pregnancy: a prospective population-based cohort study

OBJECTIVE

To investigate fetal sex dependency of maternal vascular adaptation to pregnancy as assessed by uteroplacental vascular resistance and maternal blood pressure.

DESIGN

Prospective population-based cohort study.

SETTING

Rotterdam, the Netherlands.

POPULATION

In total, 8224 liveborn singleton pregnancies were included.

METHODS

Maternal vascular adaptation was assessed in all trimesters of pregnancy. Pregnancies were stratified into being either complicated by the placental syndrome (i.e. pre-eclampsia, fetal growth restriction or preterm birth, n = 1229) or uncomplicated (n = 6995).

MAIN OUTCOME MEASURES

First trimester: blood pressures. Second trimester: blood pressures, pulsatility index of the uterine artery (PI-UtA). Third trimester: blood pressures, PI-UtA, presence of notching in the uterine artery.

RESULTS

In women carrying a male fetus PI-UtA was higher than in women with a female fetus in the total group (second trimester P < 0.001, third trimester P = 0.005). Effect estimates differed between women with or without the placental syndrome. In the total group, women with a male fetus more often showed notching in the Doppler resistance pattern (odds ratio 1.42, 95% confidence interval 1.17-1.72). Different blood pressure patterns were observed between pregnant women with a male fetus and pregnant women with a female fetus and between complicated pregnancies and uncomplicated pregnancies.

CONCLUSION

Fetal sex is significantly associated with maternal vascular adaptation to pregnancy with differential effects in uncomplicated pregnancies and in pregnancies complicated by the placental syndrome.

TWEETABLE ABSTRACT

Fetal sex is significantly associated with maternal vascular adaptation to pregnancy.

Fertility treatment, twin births, and unplanned pregnancies in women with eating disorders: findings from a population-based birth cohort

Objective

To investigate fertility treatment, twin births, and unplanned pregnancies in pregnant women with eating disorders in a population-based sample.

Design

A longitudinal population-based birth cohort (Generation R).

Setting

Rotterdam, the Netherlands.

Sample

Women from the Generation R study who reported a history of (recent or past) anorexia nervosa (n = 160), bulimia nervosa (n = 265), or both (n = 130), and a history of psychiatric disorders other than eating disorders (n = 1396) were compared with women without psychiatric disorders (n = 4367).

Methods

Women were compared on the studied outcomes using logistic regression. We performed crude and adjusted analyses (adjusting for relevant confounding factors).

Main outcome measures

Fertility treatment, twin births, unplanned pregnancies, and women's feelings towards unplanned pregnancies.

Results

Relative to women without psychiatric disorders, women with bulimia nervosa had increased odds (odds ratio, OR, 2.3; 95% confidence interval, 95% CI, 1.1–5.2) of having undergone fertility treatment. Women with all eating disorders had increased odds of twin births (anorexia nervosa, OR 2.7, 95% CI 1.0–7.7; bulimia nervosa, OR 2.7, 95% CI 1.1–6.6; anorexia and bulimia nervosa, OR 3.795% CI 1.3–10.7). Anorexia nervosa was associated with increased odds of unplanned pregnancies (OR 1.8, 95% CI 1.2–2.6) and mixed feelings about these pregnancies (adjusted OR 5.0, 95% CI 1.7–14.4). Pre-pregnancy body mass index did not explain the observed associations.

Conclusions

Eating disorders are associated with increased odds of receiving fertility treatment and twin births. Women with anorexia nervosa were more likely to have an unplanned pregnancy and have mixed feelings about the unplanned pregnancy. Fertility treatment specialists should be aware that both active and past eating disorders (both anorexia nervosa and bulimia nervosa) might underlie fertility problems.