The mediating role of pregnancy-induced hypertension on pre-pregnancy body mass index and adverse neonatal outcomes in women with assisted reproductive technology.

OBJECTIVE

To explore whether pregnancy-induced hypertension (PIH) mediates the association between pre-pregnancy body mass index (BMI) and adverse neonatal outcomes in women undergoing assisted reproductive technology (ART) for singleton pregnancies.

METHODS

This cohort study collected 79437 maternal data from the National Vital Statistics System (NVSS) between 2020 and 2021. Univariable and multivariable logistic regression models were applied to estimate the association between pre-pregnancy BMI and PIH in women receiving ART as well as the associations between pre-pregnancy BMI and PIH and adverse neonatal outcomes. The mediation effect of PIH on the association between pre-pregnancy BMI and adverse neonatal outcomes was estimated according to the total effect, natural direct effect, natural indirect effect, and percentage of mediation.

RESULTS

There were 25769 participants had adverse neonatal outcomes at the end of the follow-up. After adjusting for confounding factors, an increased risk of PIH in women receiving ART was identified in those with pre-pregnancy BMI ≥25 kg/m2 [odds ratio (OR)=1.92, 95% confidence interval (CI):1.84-2.01]. Pre-pregnancy BMI ≥25 kg/m2 was associated with an increased risk of adverse neonatal outcomes (OR = 1.26, 95%CI:1.22-1.30). Women with PIH had an increased risk of adverse neonatal outcomes (OR = 1.79, 95%CI:1.71-1.87). The percentage mediated by PIH in the association between pre-pregnancy BMI and adverse neonatal outcomes was 21.30%.

CONCLUSION

PIH partially mediated the association between pre-pregnancy BMI and adverse neonatal outcomes in women receiving ART, which recommends that women control weight before receiving ART.