The Impact of Body Mass Index on Metabolic and Pregnancy Outcomes in Patients with Polycystic Ovary Syndrome

Objective : To study the metabolic differences in polycystic ovary syndrome (PCOS) patients with different body mass indices (BMI) and to explore the effect of obesity on pregnancy outcomes in PCOS patients. Methods : A total of 1360 PCOS patients undergoing in vitro fertilization/intracytoplasmic sperm injection-embryo transfer (IVF/ICSI-ET) at Dalian Women's and Children's Medical Center (Group) from January 2015 to January 2021 were selected and divided into four groups based on BMI: underweight group (29 cases), normal weight group (562 cases), overweight group (475 cases), and obese group (294 cases). Results : Significant differences in FSH, LH, FINS, CA125, and LDL were found among the BMI groups (p<0.05). Multiple comparisons revealed that FSH, LH, and CA125 were significantly lower in the overweight and obese groups than in the normal weight group, and FINS was significantly higher in these groups. A multifactorial model showed a likelihood ratio test χ²=254.57, P<0.0001, indicating statistical significance. Additionally, AGE, LH, FINS, CHOL, HDL, and LP were associated with BMI grouping (p<0.05), while FSH, E2, PRL, CA125, LDL, TG, and Hcy were not (p≥0.05). The chi-square test indicated a significant difference in miscarriage rates across the weight groups (p<0.0001). Compared to the normal weight group, miscarriage rates tended to increase with BMI, with the obese group having significantly higher rates. Pregnancy rates for PCOS patients with BMI<23.387 and BMI≥23.387 were 29.10% and 8.94%, respectively, with a statistically significant difference. Miscarriage rates for PCOS patients with BMI<26.528 and BMI≥26.528 were 2.85% and 12.50%, respectively, also showing statistical significance. In the ROC curve of BMI and pregnancy outcomes, the sensitivity ranged from 66.7% to 67.7%; specificity values varied from a very low level of 44.3% (LDL) to 85.4% (DBP), generally higher than SHBG values. Conclusion : As BMI increases, several indicators such as fasting blood glucose, insulin, AGE, LH, CHOL, HDL, and LP show abnormalities in PCOS patients' glucose metabolism. Obese PCOS patients have higher FINS levels, suggesting that FINS may have an impact. The increase in BMI may lead to lower pregnancy rates and higher miscarriage rates.