Obesity is associated with increased risk of first trimester and recurrent miscarriage: matched case-control study

TLDR

Obesity is a global health issue linked to adverse pregnancy outcomes. The study aimed to evaluate how obesity affects miscarriage risk in the general population. Using a nested case‑control design, 1,644 obese women (BMI > 30 kg/m²) were matched by age to 3,288 normal‑weight controls (BMI 19–24.9 kg/m²) from a maternity database, focusing on primiparous women to assess early, late, and recurrent miscarriages. Obese women had significantly higher odds of early miscarriage (OR 1.2) and recurrent early miscarriage (OR 3.5), confirming obesity increases first‑trimester and recurrent miscarriage risk.

Abstract

Obesity has become a major health problem worldwide and is also associated with adverse pregnancy outcome. The aim of this study was to assess the impact of obesity on the risk of miscarriage in the general public.This was a nested case-control study. The study population was identified from a maternity database. Obese [body mass index (BMI) >30 kg/m2] women were compared with an age-matched control group with normal BMI (19-24.9 kg/m2). Only primiparous women were included in the study to avoid including the subject more than once, and to be able to correctly identify recurrent miscarriages. The prevalence of a previous history of early (6-12 weeks gestation), late (12-24 weeks gestation) and recurrent early miscarriages (REM) (more than three successive miscarriages <12 weeks) was compared between the two groups.A total of 1644 obese and 3288 age-matched normal weight controls with a mean age of 26.6 years [95% confidence interval (CI) 26.5-26.7] were included in the study. The risks of early miscarriage and REM were significantly higher among the obese patients (odds ratios 1.2 and 3.5, 95% CI 1.01-1.46 and 1.03-12.01, respectively; P = 0.04, for both].Obesity is associated with increased risk of first trimester and recurrent miscarriage.