Introduction: Hypertensive disorders of pregnancy, including gestational hypertension and preeclampsia, are influenced by parental genetic composition but few studies have explored the intergenerational recurrence of these conditions. Our objective was to quantify the association between in utero exposure to hypertensive disorders of pregnancy and the risk of gestational hypertension or preeclampsia during a woman’s first pregnancy.
Methods: We used data from the Nova Scotia 3G Multigenerational Cohort, a study that includes 18,438 women whose birth and subsequent deliveries as an adult were recorded in the Atlee Perinatal Database. The current analysis included only singleton deliveries to nulliparous women who themselves were born singleton to nulliparous or multiparous women. Logistic regression models, adjusted for potential confounders such as in utero exposure to maternal smoking and pre-pregnancy weight, were used to estimate odds ratios (OR) with 95% confidence intervals (CI) for the associations between in utero exposure and outcomes in the women’s first pregnancy.
Results: Among the 17,431 singleton-born women, 6.9% and 3.5% had codes for gestational hypertension and preeclampsia in their first pregnancy, respectively. In comparison, 8.4% and 1.5% of women were exposed in utero to gestational hypertension and preeclampsia. Compared to women born to normotensive mothers, women were at increased risk of gestational hypertension if they were exposed in utero to gestational hypertension (OR 1.8; CI 1.5, 2.1) or preeclampsia (OR 2.7; CI 1.9, 3.9). Women were at increased risk of preeclampsia if they were exposed in utero to gestational hypertension (OR 1.9; CI 1.5, 2.4) or preeclampsia (OR 3.5; CI 2.2, 5.4).
Conclusion: In this cohort, Nova Scotian women with in utero exposure to hypertensive disorders experienced increased risks of these complications in their own first pregnancy, suggesting that genetics, shared environment, or both, may play a role in development of both gestational hypertension and preeclampsia.
Stefan Kuhle– Associate Professor, Dalhousie University
Linda Dodds– Professor, Dalhousie University
Mary Margaret Brown– Trainee, Dalhousie University
Victoria Allen– Professor, Dalhousie University
Christy Woolcott– Associate Professor, Dalhousie University