Characteristics associated with uncomplicated pregnancies in women with obesity: a population-based cohort study

Maternal super obesity is increasing and is associated with an increased risk of pregnancy complications-a call for concern

OBJECTIVE

This study aimed to assess the relationship of increased body mass index (BMI) with pregnancy complications.

STUDY DESIGN

We obtained data for a retrospective cohort of singleton live births using an electronic birth certificate database from 2010 to 2022. Institutional review board exemption was obtained. BMI was assessed as a continuous variable and a categorical variable with groups of BMI 18.5-29.9 kg/m2, 40-49.9 kg/m2, and ≥50 kg/m2 compared to patients with BMI 30-39.9 kg/m2. Primary outcomes were pregnancy and maternal outcomes. Secondary outcomes were neonatal outcomes. ANOVA and χ2 were used to compare continuous and categorical variables respectively, and logistic regression was used to obtain adjusted odds ratios for primary and secondary outcomes.

RESULTS

There were 223,837 patients with singleton live births with mean BMI 27.86 kg/m2. 54,385 (24.3%) had BMI 30-39.9 kg/m2, 13,299 (5.9%) had BMI 40-49.9 kg/m2, and 1,958 (0.87%) had BMI ≥50 kg/m2. Patients with BMI > 50 kg/m2 have a higher likelihood of APGAR scores <7 (aOR 1.38, 95% CI 1.05-1.83), and NICU admission or transfer out of facility (aOR 1.17, 95% CI 1.02-1.34). In the nulliparous subgroup analysis, For patients with BMI >50 kg/m2, there was a higher odds of preterm birth <37 weeks (aOR 1.57, 95% CI 1.23-2.00) and preterm birth <34 weeks (aOR 1.51 95% CI 1.00-2.30. There is also an increased odds of cesarean section in both of these BMI groups (aOR 1.68 95% CI 1.57-1.79 and aOR 2.30 95% CI 1.94-2.72).

CONCLUSION

BMI ≥ 50 kg/m2 was significantly associated with increased pregnancy complications.

Hepcidin across pregnancy and its correlation with maternal markers of iron and inflammation, maternal body weight outcomes, and offspring neurodevelopmental outcomes: a systematic review and meta-analysis

OBJECTIVE

This study evaluated the correlation between maternal hepcidin and other biomarkers of iron status, markers of inflammation, and maternal body weight during pregnancy, as well as neurodevelopment in the offspring.

DATA SOURCES

PubMed, Web of Science, Scopus, and Embase were searched from inception until March 2022.

STUDY ELIGIBILITY CRITERIA

Studies conducted among pregnant women without apparent pregnancy complications were included. Eligible studies reported correlation coefficients between maternal hepcidin and any outcomes of maternal biomarkers of iron status or inflammatory load during pregnancy, prenatal maternal body weight, and offspring neurodevelopment. Studies without correlation data were eligible if they quantitatively reported volumes of both maternal hepcidin and any marker of iron status and/or inflammatory load during gestation.

METHODS

Pooled correlation coefficients between maternal hepcidin and outcomes of interest were calculated using the Fisher r-to-Z transformation. Both fixed-effects and DerSimonian and Laird random-effects models were used to calculate pooled correlation coefficient. When meta-analysis was not feasible, results were descriptively synthesized.

RESULTS

Forty-six studies with 6624 participants were eligible. Hepcidin was significantly correlated with hemoglobin in the third trimester (r=0.21; 95% confidence interval, 0.1-0.32); ferritin in the first (r=0.31; 95% confidence interval, 0.01-0.61) and third trimester (r=0.35; 95% confidence interval, 0.23-0.48); soluble transferrin receptor in the second trimester (r=-0.27; 95% confidence interval, -0.4 to -0.14); total iron-binding capacity in the second trimester (r=0.37; 95% confidence interval, 0.24-0.50); and serum iron in the third trimester (r=0.11; 95% confidence interval, 0.02-0.19). Hepcidin was significantly correlated with the inflammatory marker interleukin-6 in the third trimester (r=0.26; 95% confidence interval, 0.17-0.34) and C-reactive protein in the second (r=0.16; 95% confidence interval, 0.03-0.30) and third trimester (r=0.28; 95% confidence interval, 0.04-0.52). Four out of 5 studies reported weak-to-moderate positive correlation between hepcidin and body mass index. Hepcidin levels varied across body mass index categories. No single study reported the relationship between maternal hepcidin and neurodevelopment in offspring.

CONCLUSION

Hepcidin weakly to moderately correlates with biomarkers of iron and inflammation in pregnancy.

Influence of Pre-Pregnancy Obesity on Carbohydrate and Lipid Metabolism with Selected Adipokines in the Maternal and Fetal Compartment

A higher body mass index (BMI) before pregnancy is associated with an increased risk of maternal and perinatal complications. This study aimed to analyze selected parameters of carbohydrate and lipid metabolism, including adipokines, in obese pre-pregnant women, and their influence on the birth weight of newborns.

MATERIALS AND METHODS

The study group (O) consisted of 34 pregnant women with higher BMI (obese) before pregnancy. The control group (C) was 27 pregnant women with target BMI and physiological pregnancy. The BMI index: body weight [kg]/(height [m]² was assessed on the first obstetrical visit. The research material was the serum of pregnant women collected in the third trimester of pregnancy and umbilical cord blood collected immediately after delivery. Selected parameters of carbohydrate and lipid metabolism and adipokines were determined.

RESULTS

There were no statistically significant differences between the study group and the control group concerning the concentrations of insulin, glucose, VLDL, adiponectin, TNF-α, HOMA-IR, as well as LDH and cholesterol in maternal blood serum and umbilical cord blood serum. Total cholesterol and HDL in both maternal blood serum and umbilical cord blood were statistically significantly lower than those in the control group. The concentration of triglycerides (TG) and resistin in the blood serum of obese mothers were higher than those in the control group (p < 0.05). However, no statistically significant differences were found between the two groups regarding the concentrations of TG and resistin in the umbilical cord blood. The concentration of LDL cholesterol in the umbilical blood serum in the obese group was statistically significantly lower than that in the control group. The concentration of leptin in maternal blood serum and umbilical cord blood serum in the study group was statistically significantly higher than that in the control group.

CONCLUSIONS

Pregestational obesity does not substantially affect the basic parameters of carbohydrate metabolism in pregnant women, but it disturbs the lipid profile, which is manifested by a significant increase in triglycerides and a decrease in the level of HDL cholesterol in the serum. Preexisting obesity increases the concentration of leptin and resistin in the serum of pregnant women, which may be caused by the increased volume of adipose tissue. The concentrations of leptin and resistin in the blood of pregnant women correlate positively, and the concentrations of adiponectin and TNF-α negatively correlate with pre-pregnancy BMI values. There is a positive correlation between the concentration of leptin in the serum of umbilical cord blood and the birth weight of the newborn, which suggests that this parameter contributes to the pathomechanism of macrosomia.

Associations of metal mixtures in the meconium with birth outcomes in northern Taiwan

Previous studies investigated prenatal exposure to neurotoxic metals in relation to birth anthropometrics. However, limited information has been developed on associations with birth outcomes of fetal exposure to metal mixtures using the meconium as a biomarker. The purpose of this study was to evaluate relationships of the combined effects of mercury (Hg), lead (Pb), cadmium (Cd), and arsenic (As) concentrations in the meconium on birth outcomes (i.e., birth weight, birth length, and head circumference). This cross-sectional study was conducted in northern Taiwan between January 2007 and December 2009. We collected 526 meconium samples within the first 24 h after birth to measure the in utero mixed-metal exposure determined using inductively coupled plasma/mass spectrometry (ICP-MS). We used a multivariable regression and Bayesian kernel machine regression (BKMR) to estimate associations of the combined effects and identify important mixture components with growth impairments. Our results revealed Hg, Pb, Cd, and As concentrations in the meconium and enhanced the quantity of research on meconium analyses. The overall effects of Hg, Pb, Cd, and As concentrations in the meconium as prenatal exposure biomarkers were negatively associated with birth growth. Fetal exposure to Hg and Pb was correlated with decreased birth weights. Hg and Pb concentrations in the meconium were linearly inversely related to the birth weight, birth length, and head circumference. Effects of fetal exposure to As and Cd on birth outcomes were not obvious. A significant increasing relationship was detected between Hg concentrations in the meconium and maternal fish consumption during pregnancy. Higher Pb concentrations in the meconium were observed among infants of mothers who consumed Chinese herbal medicines. Reducing maternal fish consumption and Chinese herbal medicine consumption during pregnancy could limit infant exposure to metals.

ENDOCRINOLOGY IN PREGNANCY: Targeting metabolic health promotion to optimise maternal and offspring health

There is an increase in maternal metabolic burden due to the rise in pregnancies complicated by obesity, gestational diabetes, type 2 diabetes and polycystic ovary syndrome. Metabolic dysfunction during pregnancy is associated with increased risks of long-term morbidity and mortality for women and their offspring. Lifestyle interventions in pregnancy in women at risk of metabolic dysfunction have demonstrated short-term improvements such as reduced gestational weight gain and lowered risk of gestational diabetes. It is not known whether these interventions lead to sustained improvements in the metabolic health of the mother and baby. Pharmacological interventions have also shown benefits for the mother and baby in pregnancy, including improvements in glycaemic control, reduction in gestational weight gain and reduction in large for gestational age infants; however, there remains uncertainty over long-term outcomes for mother and child. Existing studies on interventions targeting metabolic health are limited to selected populations in the preconception and postpartum periods and lack follow-up beyond delivery of the intervention. The COVID-19 pandemic has refocused our attention on the effects of maternal metabolic ill-health that play a role in contributing to premature morbidity and mortality. There is an urgent need for strategies to accurately identify the growing number of women and offspring at risk of long-term adverse metabolic health. Strategies which focus on early identification and risk stratification using individualised risk scores in the pre and inter-conception periods must take priority if we are to target and improve the metabolic health of women and their offspring who are at highest risk.

Early life programming of health and disease: the long-term consequences of obesity in pregnancy: a narrative review

The prevalence of overweight and obesity is rising in all parts of the world and among young women it presents a very clear danger during pregnancy. Women who are overweight or who gain excessive weight during pregnancy are at greater risk of complications in pregnancy and labour, and are more likely to lose their child to stillbirth, or themselves die during pregnancy. This narrative review considers the evidence that in addition to increasing risk of poor pregnancy outcomes, obesity has the capacity to programme fetuses to be at greater risk of cardiometabolic disorders later in life. An extensive body of evidence from prospective and retrospective cohorts, and record linkage studies demonstrates associations of maternal obesity and/or gestational diabetes with cardiovascular disease, type-1 and type-2 diabetes. Studies in animals suggest that these associations are underpinned by adaptations that occur in fetal life, which remodel the structures of major organs including the brain, kidney and pancreas. This article is protected by copyright. All rights reserved.

Overweight, obesity and excessive weight gain in pregnancy as risk factors for adverse pregnancy outcomes: a narrative review

The global prevalence of overweight and obesity in pregnancy is rising and this represents a significant challenge for the management of pregnancy and delivery. Women who have a pre‐pregnancy body mass index greater than 25 kg m^–2 are more likely than those with a body mass index in the ideal range (20–24.99 kg m^–2) to have problems conceiving a child and are at greater risk of miscarriage and stillbirth. All pregnancy complications are more likely with overweight, obesity and excessive gestational weight gain, including those that pose a significant threat to the lives of mothers and babies. Labour complications arise more often when pregnancies are complicated by overweight and obesity. Pregnancy is a stage of life when women have greater openness to messages about their lifestyle and health. It is also a time when they come into greater contact with health professionals. Currently management of pregnancy weight gain and the impact of overweight tends to be poor, although a number of research studies have demonstrated that appropriate interventions based around dietary change can be effective in controlling weight gain and reducing the risk of pregnancy complications. The development of individualised and flexible plans for avoiding adverse outcomes of obesity in pregnancy will require investment in training of health professionals and better integration into normal antenatal care.

Overweight and obesity before pregnancy and excessive gestational weight gain are major determinants of risk for pregnancy loss, gestational diabetes, hypertensive conditions, labour complications and maternal death.

Pregnancy is regarded as a teachable moment when women are at their most receptive to messages about their health. However, unclear guidance on diet and physical activity, weight stigma from health professionals, inexperience and reluctance among professionals about raising issues about weight, and stretched resources put the health of women and babies at risk.

Excessive weight gain in pregnancy and post‐partum weight retention compromise future fertility and increase risk for future pregnancies.

Large randomised controlled trials have had little success in addressing excessive gestational weight gain or antenatal complications. Individualised, culturally sensitive and responsive interventions appear to have greater success.

Predictors of Adverse Pregnancy Outcomes in Pregnant Women Living with Obesity: A Systematic Review

Obesity is a well-recognized risk factor for pregnancy complications. Most studies to date are in large cohorts, with results presented in a way that assumes all women living with obesity are at equal risk. This study investigates which women living with obesity are at higher risk of specific pregnancy complications. A systematic search of MEDLINE and Embase identified 7894 prospective or retrospective cohort studies exploring predictors of adverse outcomes among pregnant women living with obesity. Following screening, 61 studies were deemed eligible. Studies were selected if the effects of exposure to any predictor amongst pregnant women living with obesity could be collected. Maternal characteristics assessed for association with adverse outcomes included maternal age, race/ethnicity, maternal height, mode of conception, complement activation factors, and history of various comorbidities/procedures. Gestational diabetes mellitus was the most studied outcome (n = 32), followed by preterm birth (n = 29), preeclampsia (n = 27), low birthweight infants (n = 20), small for gestational age newborns (n = 12), and stillbirth (n = 7). This review identified important characteristics that should be considered during the screening and follow-up sessions of pregnant women living with obesity, including pre-existing type 1 diabetes, maternal age < 20 years or ≥35 years, non-White ethnicity, abdominal adiposity obesity, and history of bariatric surgery.

Prediction of Healthy Pregnancy Outcomes in Women with Overweight and Obesity: The Role of Maternal Early-Pregnancy Metabolites

Women with obesity receive intensified antenatal care due to their increased risk of pregnancy complications, even though not all of these women develop complications. We developed a model based on maternal characteristics for prediction of healthy pregnancy outcomes in women with obesity or who are overweight. We assessed whether early-pregnancy metabolites improved prediction. In a population-based cohort study among a subsample of 1180 Dutch pregnant women with obesity or who are overweight, we developed a prediction model using 32 maternal socio-demographic, lifestyle, physical and pregnancy-related characteristics. We determined early-pregnancy amino acids, nonesterifed fatty acids, phospholipids and carnitines in blood serum using liquid chromatography-tandem mass spectrometry. A healthy pregnancy outcome was the absence of fetal death, gestational hypertension, preeclampsia, gestational diabetes, caesarian section, preterm birth, large-for-gestational-age at birth, macrosomia, postpartum weight retention and offspring overweight/obesity at 5 years. Maternal age, relationship status, parity, early-pregnancy body mass index, mid-pregnancy gestational weight gain, systolic blood pressure and estimated fetal weight were selected into the model using backward selection (area under the receiver operating characteristic curve: 0.65 (95% confidence interval 0.61 to 0.68)). Early-pregnancy metabolites did not improve model performance. Thus, in women with obesity or who are overweight, maternal characteristics can moderately predict a healthy pregnancy outcome. Maternal early-pregnancy metabolites have no incremental value in the prediction of a healthy pregnancy outcome.