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

Abstract

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.

Keywords: adverse outcomes; obesity; predictors; pregnancy.

Figure 1

PRISMA. * Intent of study indicates that the objective of the study was not to study the predictors of adverse pregnancy outcomes.

Figure 2

Graph illustrating the number of articles published over time.

Figure 3

(a) PE Age and Race. Acronyms: BMI = body mass index; CI = confidence interval; PE = preeclampsia. (b) PE Risk Factors. Acronyms: BMI = body mass index; T1DM = type 1 diabetes mellitus; LA= log adiponectin; CI = confidence interval; PE = preeclampsia.

Figure 4

(a) LBW Age and Race. Acronyms: BMI = body mass index; LBW = low birth weight; VLBW = very low birth weight; AI/AN = American Indian/Alaskan Native; SGA = small-for-gestational-age; CI = confidence interval. (b) LBW Risk Factors. Acronyms: BMI = body mass index; LBW = low birth weight; VLBW = very low birth weight; RWG = recommended weight gain; SGA = small-for-gestational-age; CI = confidence interval.

Figure 5

(a) Pre-term Birth Age and Race. Acronyms: BMI = body mass index; PTB = preterm birth; AI/AN = American Indian/Alaskan Native; CI = confidence interval. (b) Pre-term Birth Risk Factors. Acronyms: BMI = body mass index; PTB = preterm birth; T1DM = type 1 diabetes mellitus; MWG = maternal weight gain; GDM = gestational diabetes mellitus; IBC = interpregnancy-BMI change; CI = confidence interval.

Figure 6

(a) GDM Age and Race. Acronyms: BMI = body mass index; US = United States; CI = confidence interval. (b) GDM Risk Factors. Acronyms: BMI = body mass index; RWG = recommended weight gain; GWG = gestational weight gain; GDM = gestational diabetes mellitus; CI = confidence interval.