Pre-Pregnancy BMI and Maternal Hypertensive Risk

A study using data from the Japan Environment and Children’s Study shows that pre‑pregnancy BMI above 22.00 kg/m² is linked to a higher prevalence of hypertensive disorders of pregnancy compared with a reference BMI of 20.01–21.00 kg/m².

That threshold—below many Western counseling cutoffs—shifts attention to lower BMI bands within this population. The association persisted after multivariable adjustment (maternal age, parity, smoking, socioeconomic status) and after Bonferroni correction for multiple outcomes. In a nationwide prospective cohort of 96,796 singleton pregnancies, the observational design limits causal inference but strengthens population‑level applicability.

ROC analysis for hypertensive disorders (gestational hypertension and preeclampsia) identified a discriminative cutoff at 22.31 kg/m² (AUC 0.63; 95% CI 0.60–0.66, where reported), with a Youden‑derived sensitivity of ≈47% and specificity of ≈74%.

These diagnostic metrics indicate moderate discrimination: the cutoff flags more at‑risk individuals than the reference group but also yields substantial false negatives and positives.