Fetal sexual dimorphism in systemic soluble fms-like tyrosine kinase 1 among normotensive and preeclamptic women

Problem: A handful of studies report sexual dimorphism in the maternal angiogenic profile possibly influencing placental development and preeclampsia risk. This secondary analysis explored associations between fetal sex and soluble fms-like tyrosine kinase-1 (sFLT) and endoglin (9-35 weeks gestation) using data from a nested case-control study within the Danish National Birth Cohort. Method of study: A total of 448 preeclamptic women and 328 normotensive women had data on sFLT and endoglin. Preeclampsia was defined by blood pressure ≥140/90 mm Hg and proteinuria (≥0.3g or 300 mg/24 h.). Generalized linear models adjusting for gestational age of blood draw, body mass index, maternal age, and smoking determined associations between fetal sex and log-transformed biomarkers. Results: Male fetal sex is associated with 11% lower sFLT levels (β = −0.11, P = 0.03) in preeclamptic women. There were no differences observed in normotensive women. We found no statistically significant differences in endoglin by fetal sex among groups. Conclusion: Our results are similar with other studies suggesting that women with female fetuses have increased sFLT levels. However, significant difference was only among women with preeclampsia. This study was exploratory and longitudinal investigations across pregnancy are required to understand the relationship between fetal sex and systemic maternal angiogenic biomarkers.