Maternal Hypertension During Pregnancy Shows Sex-Specific Effects on Fetal Growth

Recent research highlights the impact of hypertensive disorders during pregnancy (HDPs) on fetal development, revealing that the effects vary depending on the sex of the fetus. HDPs, including chronic hypertension and gestational hypertension, are characterized by elevated blood pressure during pregnancy and are associated with serious health risks for both mother and baby, such as preterm birth and increased infant mortality.

One significant concern is that HDPs can impair blood flow to the placenta, which may limit oxygen and nutrient delivery to the developing fetus. While previous studies have shown inconsistent results regarding fetal and placental growth responses to maternal hypertension, emerging evidence suggests these effects might be sex-dependent.

A study conducted by Alexandra R. Sitarik and colleagues, published in Pediatric Investigation, investigated whether the relationship between HDPs and fetal growth markers differs by sex. Using data from the Wayne County Health Environment Allergy and Asthma Longitudinal Study (WHEALS), the researchers analyzed 853 pregnancies, focusing on measures such as birthweight and placental weight, while adjusting for relevant confounders.

The findings revealed that male fetuses born to mothers with gestational hypertension exhibited higher birthweight Z-scores compared to those with normal blood pressure. Conversely, female fetuses did not show this pattern. Intriguingly, in more complicated pregnancies, female babies exposed to hypertension exhibited lower birthweights, whereas males continued to display increased growth.

Further analysis of placental-to-birthweight ratios indicated that female fetuses exposed to HDPs had reduced ratios, suggesting a potential prioritization of placental development over fetal growth as a survival strategy. These sex-specific growth patterns align with the growth strategy hypothesis, which proposes that male fetuses are less adaptable to prenatal stressors, while females may adapt by enhancing placental function.

Understanding these differences is crucial for improving prenatal care and risk assessment. Recognizing that fetal response to hypertension varies by sex can help clinicians tailor interventions, ultimately supporting healthier outcomes for both mothers and infants. This study underscores the importance of considering fetal sex in research and clinical management of hypertensive pregnancy disorders.

Source: https://medicalxpress.com/news/2025-08-maternal-hypertension-pregnancy-linked-fetal.html