ASSOCIATION OF GLUCOSE INTOLERANCE WITH PIH (PREGNANCY-INDUCED HYPERTENSION)

Abstract

Background: Hypertensive disorders of pregnancy (gestational hypertension and preeclampsia) affect roughly 3–10% of pregnancies worldwide and contribute to significant maternal-fetal morbidity. Preeclampsia alone is responsible for an estimated 50,000 maternal deaths each year. In parallel, gestational diabetes mellitus (GDM) is increasingly common (affecting ~7–15% of pregnancies globally) and shares risk factors with preeclampsia. We hypothesized that maternal glucose intolerance (GDM or pre-existing diabetes) elevates the risk of developing pregnancy-induced hypertension (PIH).

Methods: We conducted a prospective cohort study at a tertiary care hospital in Pakistan (2024–2025). Pregnant women <20 weeks gestation without chronic hypertension were enrolled (n=1200). They were categorized by glycemic status: normoglycemic, GDM (diagnosed by IADPSG OGTT criteria), or pregestational diabetes. All participants were followed for new-onset PIH (gestational hypertension or preeclampsia by standard definitions). We compared PIH incidence between groups and used logistic regression to adjust for confounders.

Results: PIH occurred in 73 of 1200 pregnancies (6.1%). The incidence of PIH was markedly higher in women with glucose intolerance: 15.0% in GDM and 20.8% in pre-existing diabetes, versus 4.7% in normoglycemic pregnancies (p<0.001). GDM was associated with a ~3.5-fold increased odds of PIH (unadjusted OR 3.55, 95% CI 2.0–6.3), and pre-existing diabetes with ~5.3-fold odds (OR 5.29, 95% CI 1.9–14.8) compared to normoglycemic women. These associations remained significant after adjusting for age, BMI, and parity.

Conclusions: Maternal glucose intolerance is independently associated with a higher risk of PIH. Women with GDM or pregestational diabetes should receive vigilant antenatal surveillance and risk factor management to mitigate hypertensive complications. Our findings underscore the importance of integrated obstetric and medical care for high-risk pregnancies.