Association of fetal gender and the onset and severity of hypertensive disorders of pregnancy.

Objective: It was reported that fetal gender was associated with gestational-age related incidence of preeclampsia. However, there is no study to date to evaluate the association of fetal gender differences with all hypertensive disorders of pregnancy. The present study aimed to evaluate the association, if any, between fetal gender differences and the disposition to develop hypertensive disorders of pregnancy and the risk of developing severe features.

Methods: This was a single site retrospective cohort that included patients who were diagnosed with either gestational hypertension, preeclampsia without severe features, severe preeclampsia, superimposed preeclampsia, or superimposed preeclampsia with severe features. Patients were divided into two groups based on male versus female fetal gender. Our primary outcome was gestational age (GA) at diagnosis of hypertensive disorder. GA ranges evaluated were <28 weeks, 28-34 weeks, 34-37 weeks, and >37 weeks. Secondary outcomes were maternal morbidity (severe features at delivery, HELLP syndrome, placental abruption, eclampsia, maternal death, and maternal intensive care unit (ICU) admission), GA range at delivery, indication for delivery, and fetal outcomes. Continuous data were analyzed using an unpaired t-test and categorical data was analyzed using Chi-square test. A probability level was <.05 was set as statistically significant.

Results: A total of 597 patients were included, 275 with male fetus and 322 with female fetus. Demographic comparison between the two groups showed similar rates in patients complicated with chronic hypertension, but a higher incidence of antihypertensive medication used in the male fetus group,  < .05. All other demographics were similar between the two groups. There were no significant differences in maternal primary and secondary outcomes, including GA range at diagnosis and severe features at delivery, and fetal outcomes, including neonatal intensive care unit (NICU) admission, evaluated between the two groups.

Conclusion: Our study did not find significant differences between fetal gender and GA at the diagnosis of hypertensive disorders of pregnancy or development of severe features in the study subjects.