Elevated triglyceride-glucose body mass index increases risk of miscarriage in women undergoing in vitro fertilization and embryo transfer.

Abstract

OBJECTIVE To explore the effects of triglyceride-glucose body mass index (TyG-BMI) on pregnancy outcome of in vitro fertilization and embryo transfer (IVF-ET). DESIGN Retrospective cohort study. SUBJECTS This study included clinical data from 17365 patients across three reproductive medicine centers in China, encompassing both fresh embryo transfer (ET) cycles and subsequent frozen-thaw embryo transfer (FET) cycles. EXPOSURE The subjects were categorized into four groups according to the TyG-BMI quartiles measured prior to cycle initiation: Quartile 1 (Q1): < 166.9, Quartile 2 (Q2): 166.9-188.8, Quartile 3 (Q3): 188.8-218.8, Quartile 4 (Q4): ≥ 218.8. MAIN OUTCOME MEASURES Primary outcome: cumulative live birth rate (CLBR). Second outcome: biochemical pregnancy rate, clinical pregnancy rate, miscarriage rate and live birth rate. RESULTS A higher TyG-BMI was significantly associated with increased miscarriage rates (fresh ET cycles: Q4 vs Q1: OR=1.41, 95%CI: 1.09-1.83, P=0.008; FET cycles: Q2 vs Q1: OR=1.24, 95%CI: 1.06-1.45, P<0.001; Q3 vs Q1: OR=1.36, 95%CI: 1.17-1.60, P<0.001; Q4 vs Q1: OR=1.57, 95%CI: 1.34-1.84, P<0.001) in both fresh ET and FET cycles. Additionally, a higher TyG-BMI was associated with lower live birth rate (Q4 vs Q1: OR=0.88, 95%CI: 0.80-0.97, P=0.011) in FET cycles. In cumulative cycles, patients with a higher TyG-BMI exhibited a significantly lower CLBR (Q2 vs Q1: OR=0.90, 95%CI: 0.82-0.99, P=0.025; Q3 vs Q1: OR=0.87, 95%CI: 0.79-0.95, P=0.003; Q4 vs Q1: OR=0.78, 95%CI: 0.71-0.85, P<0.001). The linear negative correlation between the TyG-BMI and CLBR was further confirmed by the restricted cubic splines (P-non-linear = 0.159, P-overall < 0.001). Subgroup analyses based on age and ovarian reserve revealed that a high TyG-BMI had a more pronounced adverse impact on younger women (<35y) and those with polycystic ovary syndrome (PCOS) or normal ovarian reserve. However, this association was not observed in older patients (≥35y) or those with diminished ovarian reserve (DOR). CONCLUSIONS As TyG-BMI increased, the miscarriage rates in fresh ET and FET cycles increased, while live birth rates in FET cycles and cumulative live birth rates declined. These findings suggest that TyG-BMI may serve as a practical marker for identifying patients at increased metabolic risk for adverse pregnancy outcomes prior to IVF treatment.