Superfertility is more prevalent in obese women with recurrent early pregnancy miscarriage

Abstract

Objective: To investigate the effects of obesity on superfertility.

Design: Retrospective observational study.

Setting: A tertiary referral implantation clinic.

Population: Four hundred and fourteen women attending a tertiary implantation clinic with a history of recurrent miscarriage (RMC), over a 4-year period.

Methods: Pattern of pregnancy loss and time to pregnancy intervals for each pregnancy were collected by medical staff from women with RMC. The women were categorised into normal, overweight and obese according to their body mass index (BMI). Kaplan-Meier curves were constructed estimating the cumulative probability of a spontaneous pregnancy over time. The pregnancy loss patterns were correlated with BMI and data were compared between the categories using the Kruskal-Wallis test.

Main outcome measures: Pregnancy loss pattern and time to pregnancy intervals.

Results: Overall, 23.2, 51.4 and 64.2% of women conceived within first 1, 3 and 6 months, respectively. Obese women had cumulative pregnancy rates of 65.2 and 80% by three and 6 months, respectively, which was more than the cumulative pregnancy rates for women with normal BMI (49.2 and 65.8%). Comparison of survival curves indicated a significant difference in time to conceive for obese when compared with normal and overweight women (*P = 0.01), suggesting a higher prevalence of superfertility in obese women with RMC.

Conclusions: Our findings suggest that obese women may have a greater efficacy to achieve pregnancy, but with an increased risk of miscarriage, which may suggest the possible metabolic effects of obesity on endometrium.

Keywords: Obesity; recurrent miscarriage; superfertility.