High Maternal Body Mass Index in Early Pregnancy and Risks of Stillbirth and Infant Mortality—A Population-Based Sibling Study in Sweden

Abstract

In a population-based case-control study, we investigated whether familial confounding influenced the associations between maternal overweight/obesity and risks of stillbirth and infant mortality by including both population and sister controls. Using nationwide data from the Swedish Medical Birth Register (1992–2011), we included all primiparous women with singleton births who also had a sister with a first birth during that time period. We used logistic regression analyses to calculate odds ratios (and 95% confidence intervals) adjusted for maternal age, height, smoking habits, education, and time period (5-year groups) of child's birth. Body mass index (BMI) was calculated as weight (kg)/height (m)2. Compared with population controls with a normal BMI (18.5–24.9), stillbirth risk increased with increasing BMI (BMI 25–29.9: odds ratio (OR) = 1.51 (95% confidence interval (CI): 1.21, 1.89); BMI 30–34.9: OR = 1.77 (95% CI: 1.24, 2.50); BMI ≥35: OR = 3.16 (95% CI: 2.10, 4.76)). The sister case-control analyses revealed similar results. Offspring of obese women (BMI ≥30) had an increased risk of infant mortality when population controls were used (OR = 2.41, 95% CI: 1.83, 3.16), and an even higher risk was obtained when sister controls were used (OR = 4.04, 95% CI: 2.25, 7.25). We conclude that obesity in early pregnancy is associated with increased risks of stillbirth and infant mortality independently of genetic and early environmental risk factors shared within families.

Maternal Overweight and Obesity and Genital Anomalies in Male Offspring: A Population‐Based Swedish Cohort Study

“…The escalation of overweight and obesity among women of childbearing ages has short‐ and long‐term consequences for the developing fetus. Most obese pregnant women give birth to healthy children but they face higher risk of adverse outcomes, including early pregnancy loss, stillbirth, and infant mortality . Further, an overall increased risk of congenital anomalies has been described …”

“…Most obese pregnant women give birth to healthy children but they face higher risk of adverse outcomes, including early pregnancy loss, stillbirth, and infant mortality. 1 Further, an overall increased risk of congenital anomalies has been described. 2 Cryptorchidism (incomplete testicular descent) and hypospadias (displacement of the urethral meatus on the ventral side of the penis) are the two most common urogenital anomalies in boys.…”

Findings in Stillbirths Associated with Placental Disease

“…This is consistent with previous case-control analyses showing that increased BMI is associated with all-cause stillbirth. [12][13][14][15] Our analysis is the only one to focus on placental disease, providing evidence that elevated BMI is associated with abnormal placental development and/or function. Tobacco use has also long been associated with stillbirth and other adverse pregnancy outcomes linked to placental disease such as FGR and placental abruption.…”

Maternal mortality in the indigenous and non-indigenous population in Pará: contribution to the surveillance of deaths

“…29 In terms of the distribution of deaths, according to Chapter 15 of the ICD-10, disorders associated with oedema, proteinuria and hypertensive disorders during pregnancy, childbirth and the puerperium (ICD O10-O16) stood out when compared to others, equivalent to an absolute number of 270 (30.5%) cases, similar to the results of other studies. [31][32][33][34] Hypertensive diseases are predominantly found in this group. Childbirth complications, whose absolute number was 194 (ICD O60 -O75) and complications in the puerperium (n = 149) (ICD O85-O92) also had a significantly high value.…”