P-691 Effect of body mass index on early and late pregnancy loss in women with polycystic ovary syndrome undergoing in vitro fertilization and embryo transfer
Authors: Huang S , Yang R , Wang H , Li R 
Published: July 2024

Abstract

Study question
Are early and late pregnancy loss both affected by elevated body mass index (BMI) in women with polycystic ovary syndrome (PCOS) undergoing IVF-ET?

Summary answer
Late pregnancy loss but not early pregnancy loss was adversely affected by elevated BMI in women with PCOS undergoing IVF-ET.

What is known already
PCOS, the most common endocrine disorder in women of reproductive age, affects 5–18% of women. Obesity appears to be closely associated with PCOS. High BMI of the women with PCOS has been clearly associated with pregnancy loss. However, available data are limited for distinguishing between early and late pregnancy loss in PCOS women with different BMI and age. We performed a large cohort study of PCOS women conceived after IVF-ET to access the risk of early and late pregnancy loss.

Study design, size, duration
A retrospective cohort study of 3213 pregnancies after IVF-ET in women with PCOS from January 2015 to October 2022.

Participants/materials, setting, methods
The participants were the PCOS women with a positive human chorionic gonadotropin (hCG) after IVF-ET treatment in the reproductive centre of an university hospital. We studied early (≤12 weeks and biochemical pregnancy loss included) and late (&gt;12 weeks) pregnancy loss in overweight group (BMI≥24 kg/m2) compared to normal group (BMI&lt;24 kg/m2).

Main results and the role of chance
From 3213 PCOS women conceived after IVF-ET treatment, 1715 (53.4%) women were in overweight group and 1498 (46.6%) in normal group. Baseline characteristics age, primary infertility, pregnancy loss history, endometrial thickness, numbers and types of embryo transferred were not different between two groups. Overweight women had higher serum basal total testosterone and androstenedione levels. Early pregnancy loss (EPL) occurred in 24.2% (415) of overweight women with PCOS versus 21.6% (323) of those with normal weight (OR 1.16, 95% CI 0.98–1.37, P = 0.08). Rates of ELP were also comparable in both groups stratified by age. Overweight women had higher rates of late pregnancy loss (LPL) (6.6% in overweight group versus 3.3% in normal group, OR 2.11, 95% CI 1.50–3.00, P &lt; 0.001). In subgroup analyses, young and advanced-age women with PCOS both had increased chances of LPL with elevated BMI. Logistic regression showed BMI was an independent risk factor of LPL considering age, androgen level, history of previous pregnancy loss, and infertility type.

Limitations, reasons for caution
Due to the retrospective study, records about gestation-related disease history and smoking were not complete and not shown. However, all patients with IVF-ET were asked to control gestation-related conditions suitable for pregnancy. Proportion of smoking was low and women who planned to conceive were advised to stop smoking before treatment.

Wider implications of the findings
This study enables physicians to counsel PCOS women undergoing IVF their risk of pregnancy loss more accurately based on personal characteristics.

Trial registration number
not applicable