Obesity Increases the Risk of Spontaneous Abortion during Infertility Treatment

TLDR

Obesity is a modifiable, low‑cost risk factor for spontaneous abortion, making its control a priority among known predictors. The study investigates whether higher body mass index increases the risk of spontaneous abortion in women undergoing infertility treatment. Using a retrospective cohort of 2,349 pregnancies from 1987‑1999, the authors stratified patients into five BMI categories and applied logistic regression to assess abortion risk. After adjustment, overweight, obese, and very obese women had progressively higher abortion rates (p<0.05, p<0.01, p<0.001), with an overall 20% incidence, confirming a positive BMI‑abortion relationship.

Abstract

Abstract Objective: This study examines the relationship between body mass and the risk of spontaneous abortion in a large cohort of patients who received infertility treatment. Research Methods and Procedures: This is a retrospective study using data on pregnancies ( n = 2349) achieved after treatment in a tertiary medical center from 1987 to 1999. One pregnancy per subject was included, and the subjects were stratified into five body mass groups based on body mass index (BMI): underweight, &lt;18.5 kg/m 2 ; normal, 18.5 to 24.9 kg/m 2 ; overweight, 25 to 29.9 kg/m 2 ; obese, 30 to 34.9 kg/m 2 ; and very obese, ≥35 kg/m 2 . Logistical regression analysis was used. Results: The overall incidence of spontaneous abortion was 20% (476 of 2349). The effect of BMI on the risk of spontaneous abortion was significant after adjusting for several independent risk factors. Compared with the reference group (BMI 18.5 to 24.9 kg/m 2 ), underweight women had a similar risk of spontaneous abortion, whereas there was progressive increase of risk in overweight, obese, and very obese groups ( p &lt; 0.05, p &lt; 0.01, and p &lt; 0.001, respectively). Discussion: Of all known risk factors for spontaneous abortion, the control of obesity has great significance because it is noninvasive, potentially modifiable, possibly amenable to low cost, and self‐manageable by patients. This study established a positive relationship between BMI and the risk of spontaneous abortion in women who became pregnant after assisted reproductive technology treatment.