Effect of Obesity on Gestational and Perinatal Outcomes

Association of high pre-pregnancy body mass index with adverse maternal and perinatal outcomes

Background & Objectives

Obesity is an epidemic of the 21st century with its rates doubling in both developed and developing countries. It raises concerns for both maternal and fetal well-being and needs altered care throughout pregnancy and in postnatal period. Raised BMI prior to conception is associated with adverse feto-maternal outcomes. Limited data is available about its association with adverse maternofetal outcome in this region of the world. Our objective was to find out association of high pre-pregnancy BMI with adverse maternal and perinatal outcomes.

Methods

This cohort study of 390 patients was conducted in Gynae department of Lady Reading Hospital Peshawar. Study duration was from June 2021 to March 2022. Patients enrolled in third trimester of gestation (≥ 37 weeks) were divided into two groups based on BMI i.e., Group-A with BMI <25 and Group-B with BMI ≥ 25. Both groups were followed until their delivery and discharge.

Results

The mean age of 390 women was 28.2 ± 4.8 years. There was statistically significant association between raised pre pregnancy BMI and maternal risks like postpartum hemorrhage (p-0.0001), genital tract (p-0.0002) and perineal trauma (p-0.04). Neonatal risks significantly associated with high pre-pregnancy BMI were macrosomia (p-0.0001), and one minute APGAR score of < 8/10(p- 0.01). Both groups had no statistically significant difference for different modes of delivery i.e normal vaginal/ instrumental delivery and cesarean section (P-value 0.9).

Conclusion

Maternal pre-conception BMI of ≥ 25 leads to poor maternal and perinatal outcomes.

Risk of neural tube defects according to maternal body mass index: a systematic review and meta-analysis

INTRODUCTION

The aim of our systematic review and meta-analysis was to evaluate the risk of neural tube defects (NTDs) according to the pre-pregnancy body mass index.

MATERIALS AND METHODS

Electronic databases were searched (MEDLINE, EMBASE, Web of Sciences, Scopus, ClinicalTrial.gov, OVID, and Cochrane Library). Selection criteria included prospective and retrospective cohort studies reporting the prevalence of fetal NTDs in obese, overweight, and underweight pregnant women. Odds ratios (ORs) comparing risk among these subsets of pregnancies with normal weight mothers were determined with 95% confidence intervals (CI). The evaluated outcome was the association between maternal underweight, overweight, and obesity and the risk of NTDs.

RESULTS

We included ten studies published between 2000 and 2017, including underweight, overweight, and obese pregnant women with fetal NTD (cases) and pregnant women with recommended BMI with fetal NTD (controls). Compared with normal BMI women, obese mothers were at significantly higher risk of fetal NTDs (0.53 vs. 0.33%; OR 1.62 95% CI 1.32-1.99, p < .0001), while no difference for the risk of NTDs was found when comparing overweight (0.34 vs. 0.32%; OR 1.09 95% CI 0.92-1.3, p = .3) and underweight (0.65 vs. 0.24%; OR 1.34 95% CI 0.73-2.47, p = .34) with normal weight pregnant women.

DISCUSSION

Obese pregnant women are at significantly higher risk NTDs, while no significant difference has been found in overweight and underweight pregnant women. Key message Obese pregnant women are at significantly higher risk of NTDs, such as spina bifida compared with normal weight women. No difference was found when comparing overweight and underweight with normal weight women.

Association of Maternal Body Mass Index With Risk of Infant Mortality: A Dose-Response Meta-Analysis

Objective: This study presumed that a high or low body mass index (BMI) might increase the risk of infant mortality. Therefore, a meta-analysis was performed to systematically assess the association between maternal BMI and the risk of infant mortality. Methods: The electronic databases, including Pubmed, Embase database, and Cochrane Library, were systemically searched by two investigators from inception to November 26th, 2020, with no language restriction. In parallel, a dose-response was assessed. Results: Finally, 22 cohort studies involving 13,532,293 participants were included into this paper, which showed that compared with normal BMI, maternal overweight significantly increased the risks of infant mortality [risk ratio (RR), 1.16; 95% confidence interval (CI), 1.13-1.19], neonatal mortality (RR, 1.23; 95% CI, 1.08-1.39), early neonatal mortality (RR, 1.55; 95% CI, 1.26-1.92) and post-neonatal mortality (RR, 1.18; 95% CI, 1.07-1.29). Similarly, maternal obesity significantly increased the risk of infant mortality (RR, 1.55; 95% CI, 1.41-1.70), neonatal mortality (RR, 1.55; 95% CI, 1.28-1.67), early neonatal mortality (RR, 1.37; 95% CI, 1.13-1.67), and post-neonatal mortality (RR, 1.30; 95% CI, 1.03-1.65), whereas maternal underweight potentially decreased the risk of infant mortality (RR, 0.93; 95% CI, 0.88-0.98). In the dose-response analysis, the risk of infant mortality significantly increased when the maternal BMI was >25 kg/m². Conclusions: Maternal overweight or obesity significantly increases the risks of infant mortality, neonatal mortality, early neonatal mortality, and post-neonatal mortality compared with normal BMI in a dose-dependent manner. Besides, maternal underweight will not increase the risk of infant mortality, neonatal mortality, early neonatal mortality, or postneonatal mortality; instead, it tends to decrease the risk of infant mortality. Early weight management may provide potential benefits to infants, and more large-scale prospective studies are needed to verify this finding in the future.

Trends in Selected Chronic Conditions and Related Risk Factors Among Women of Reproductive Age: Behavioral Risk Factor Surveillance System, 2011-2017

Introduction: Chronic diseases in the United States are the leading drivers of disability, death, and health care costs. In women of reproductive age (WRA), chronic disease and related risk factors can also affect fertility and reproductive health outcomes. This analysis of trends from 2011 to 2017 adds additional indicators and updates an analysis covering 2001-2009. Methods: Data from the 2011-2017 Behavioral Risk Factor Surveillance System were analyzed for 265,544 WRA (18-44 years). To assess trends in 12 chronic conditions and related risk factors, we calculated annual prevalence estimates and adjusted prevalence ratios (APRs) with predicted marginals accounting for age, race, Hispanic ethnicity, education, and health care coverage. Results: From 2011 to 2017, prevalence decreased for current smoking (20.7%-15.9%; p < 0.001), gestational diabetes (3.1%-2.7%; p = 0.003), and high cholesterol (19.0%-16.7%; p < 0.001); prevalence increased for depression (20.4%-24.9%; p < 0.001) and obesity (24.6%-27.6%; p < 0.001). After adjustment, in 2017 WRA were more likely to report asthma (APR = 1.06; 95% confidence interval [CI] = 1.01-1.11), physical inactivity (APR = 1.08; 95% CI = 1.04-1.12), obesity (APR = 1.15; 95% CI = 1.11-1.19), and depression (APR = 1.29; 95% CI = 1.25-1.34) compared with 2011. They were less likely to report high cholesterol (APR = 0.89; 95% CI = 0.85-0.94) in 2015 compared with 2011, and current smoking (APR = 0.86; 95% CI = 0.82-0.89) and gestational diabetes (APR = 0.84; 95% CI = 0.75-0.94) in 2017 compared with 2011. Conclusions: Some chronic conditions and related risk factors improved, whereas others worsened over time. Research clarifying reasons for these trends may support the development of targeted interventions to promote improvements, potentially preventing adverse reproductive outcomes and promoting long-term health.

[Factors related to severe neonatal acidosis in planned cesarean section. A case-control study]

OBJECTIVES

To identify factors related to the occurrence of severe neonatal acidosis in case of planned caesarean section.

METHODS

Case-control study conducted between 1997 and 2016 among women with planned caesarean delivery at term. Cases were women whose neonates had neonatal arterial pH<7,0. For each case, two planned caesarean sections with neonatal pH≥7,0 were selected as controls. Women whose fetus had a congenital malformation and those whose anesthesia was not spinal anesthesia were excluded.

RESULTS

Among the 5014 planned cesarean sections of the study period, 38 severe neonatal acidosis were observed (incidence of 0,76% CI95 [0,54-1,04]). Compared to 72 controls, the 36 caesareans with severe neonatal acidosis were associated with more frequent maternal obesity (BMI≥30kg/m²), higher ephedrine doses, longer time from skin incision to infant delivery, and more extraction difficulties. After logistic regression, only maternal obesity remained associated with a significant increase in the risk of severe neonatal acidosis, ORa=3,73, 95%CI (1,11-12,56).

CONCLUSIONS

In case of planned cesarean section, the main risk factor for severe neonatal acidosis is the existence of maternal obesity.

Maternal obesity and the risk of fetal acidosis at birth

Background: Maternal obesity is a risk factor for multiple obstetrics complications and adverse outcomes. The objective of the study was to investigate the association between obesity (IMC >30) and fetal acidosis at birth.Methods and findings: This hospital-based cohort study was based on 24,307 live-born infants in which maternal body mass index (BMI) information was available and delivered in the Granada north region during 2007-2018 from data of the Hospital Medical Birth Registry. Multivariate using logistic regression was performed to assess the association between fetal acidosis and BMI, crude, and adjusted odds ratio of fetal acidosis were calculated. p < .05 was considered statistically significant. We adjusted by maternal age, parity, hypertension, diabetes, and smoking habits. In the study population of 17,167 term live births, 518 infants (3.02%) had an umbilical cord blood pH < 7.10. The obesity rate in mothers with acidosis at delivery was 12.7%, but morbid obesity rate was 2.51% (adjusted OR 1.82).Conclusion: This study strengthens the evidence that demonstrates that morbid obesity is an independent risk factor for fetal acidosis at birth.

Predictors of excess birth weight in Brazil: a systematic review

OBJECTIVE

To describe the main predictors for excess birth weight in Brazilian children.

DATA SOURCES

Systematic review carried out in the bibliographic databases: PubMed/MEDLINE, Cochrane, Scopus, Web of Science, and LILACS. The research in the gray literature was performed using the Google Scholar database. The bias risk analysis was adapted from the Downs and Black scale, used to evaluate the methodology of the included studies.

DATA SYNTHESIS

Using the classifications of fetal macrosomia (>4.000g or ≥4.000g) and large for gestational age (above the 90th percentile), 64 risk factors for excess birth weight were found in 33 scientific articles in the five regions of the country. Of the 64 risk factors, 31 were significantly associated with excess birth weight, with excess gestational weight gain, pre-gestational body mass index ≥25kg/m², and gestational diabetes mellitus being the most prevalent.

CONCLUSION

The main predictors for excess birth weight in Brazil are modifiable risk factors. The implementation of adequate nutritional status in the gestational period and even after childbirth appears to be due to the quality and frequency of the follow-up of the mothers and their children by public health agencies.

Maternal overweight and obesity increase the risk of fetal acidosis during labor

OBJECTIVE

To investigate whether maternal overweight and obesity increased the risk of fetal acidosis measured in umbilical cord arterial blood after delivery.

STUDY DESIGN

Population-based cohort study of 84,785 term (≥37 weeks) infants. Logistic regression was used to estimate risks of fetal acidosis in umbilical cord arterial blood. Fetal acidosis was defined as pH <7.10 or as pH <1st percentile on a normal reference curve.

RESULT

Risks of fetal acidosis increased, regardless of definition, with maternal overweight and obesity severity. Compared to normal weight (BMI 18.5-<25), the odds ratios (95% confidence interval) for pH <7.10 were 1.35 (1.23-1.47) for overweight (BMI 25-<30), 1.46 (1.27-1.69) for mild obesity (BMI 30-<35), and 1.75 (1.42-2.15) for severe obesity (BMI ≥35). The association for obesity was attenuated in analyses restricted to non-instrumental vaginal deliveries.

CONCLUSION

Maternal overweight and obesity increased the risk of fetal acidosis. More complicated deliveries in obese women may partially explain this association.

Foetoplacental epigenetic changes associated with maternal metabolic dysfunction

Metabolic-related diseases are attributed to a sedentary lifestyle and eating habits, and there is now an increased awareness regarding pregnancy as a preponderant window in the programming of adulthood health and disease. The developing foetus is susceptible to the maternal environment; hence, any unfavourable condition will result in foetal physiological adaptations that could have a permanent impact on its health. Some of these alterations are maintained via epigenetic modifications capable of modifying gene expression in metabolism-related genes. Children born to mothers with dyslipidaemia, pregestational or gestational obesity, and gestational diabetes mellitus, have a predisposition to develop metabolic alterations during adulthood. CpG methylation-associated alterations to the expression of several genes in the human placenta play a crucial role in the mother-to-foetus transfer of nutrients and macromolecules. Identification of epigenetic modifications in metabolism-related tissues of offspring from metabolic-altered pregnancies is essential to obtain insights into foetal programming controlling newborn, childhood, and adult metabolism. This review points out the importance of the foetal milieu in the programming and development of human disease and provides evidence of this being the underlying mechanism for the development of adulthood metabolic disorders in maternal dyslipidaemia, pregestational or gestational obesity, and gestational diabetes mellitus.

Hematopoietic changes in the offspring induced by maternal overweight: Effect on placenta and fetal liver populations

INTRODUCTION

Bone marrow cells (BMC) from obese adult mice display an increased apoptosis rate over proliferation. Hematopoietic stem cells (HSC) form all blood cells and are important BMC used in cell therapy. Because it is known that prenatal development can be affected by adverse metabolic epigenetic programming from the maternal organism, this work aimed to investigate the effects of maternal overweight on placenta and fetal liver hematopoietic niches.

METHODS

Overweight was induced in female mice by overfeeding during lactation. After Swiss females were mated with healthy males, fetuses at 19 dpc (day post conception) and placentas were analyzed. Maternal biometric parameters were compared, and hematopoiesis in the dissociated placenta and fetal liver cells was analyzed by flow cytometry. Placenta morphology and protein content were also studied.

RESULTS

The model induced accumulation of adipose tissue, weight gain, and maternal hyperglycemia. Placentas from the overfed group (OG) displayed altered morphology, higher carbohydrate and lipid deposition, and increased protein content of fibronectin and PGC-1α. Cytometric analysis showed that placentas from OG presented a higher percentage of circulating macrophages, endothelial progenitor cells, HSC, and progenitor cells. No difference was detected in the percentage of neutrophil granulocytes and total leukocytes or in the proliferation of total cells, HSC, or total leukocytes. With regard to liver analysis of the OG group, there was a significant increase in circulating macrophages, primitive HSC, and oval cells but no difference in hematopoietic progenitor cells, total leukocytes, or leukocyte or total cell proliferation.

CONCLUSION

Unregulated maternal metabolism can affect hematopoietic populations within the placenta and fetal liver.