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

OBJECTIVE

To explore the effects of triglyceride glucose-body mass index (TyG-BMI) on pregnancy outcomes of in vitro fertilization and embryo transfer.

DESIGN

Retrospective cohort study.

SUBJECTS: This study included clinical data from 17,365 patients across 3 reproductive medicine centers in People's Republic of China, encompassing both fresh embryo transfer (ET) cycles and subsequent frozen-thawed embryo transfer (FET) cycles.

EXPOSURE: The subjects were categorized into four groups according to the TyG-BMI quartiles measured before 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).

SECONDARY OUTCOMES: 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: odds ratio [OR] = 1.41, 95% confidence interval [CI]: 1.09-1.83; FET cycles: Q2 vs. Q1: OR = 1.24, 95% CI: 1.06-1.45; Q3 vs. Q1: OR = 1.36, 95% CI: 1.17-1.60; Q4 vs. Q1: OR = 1.57, 95% CI: 1.34-1.84) 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) 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; Q3 vs. Q1: OR = 0.87, 95% CI: 0.79-0.95; Q4 vs. Q1: OR = 0.78, 95% CI: 0.71-0.85). The linear negative correlation between the TyG-BMI and CLBR was further confirmed by the restricted cubic splines. Subgroup analyses based on age and ovarian reserve revealed that a high TyG-BMI had a more pronounced adverse impact on younger women (<35 y) and those with polycystic ovary syndrome or normal ovarian reserve. However, this association was not observed in older patients (≥35 y) or those with diminished ovarian reserve.

CONCLUSION

As TyG-BMI increased, the miscarriage rates in fresh ET and FET cycles increased, whereas live birth rates in FET cycles and CLBR declined. These findings suggest that TyG-BMI may serve as a practical marker for identifying patients at increased metabolic risk for adverse pregnancy outcomes before in vitro fertilization treatment.