Association between fetal sex and preeclampsia: a case-control study

Even though some underlying biological mechanisms and epidemiological evidence are still unclear, sexual dimorphism seems to play an important role in obstetric complications such as preeclampsia. Parity status has not been frequently considered in determining the risk of preeclampsia in previous studies. This study aimed to determine the association between fetal sex and preeclampsia, stratified by parity status.

Case-control study conducted between October 2023 and October 2024 in the medical records of Mexican patients from northeastern Mexico.

preeclampsia. Cases were defined as women diagnosed with preeclampsia according to standardized criteria; the control group (n = 976) did not meet those criteria. The independent variable was the fetal sex; the statistical power of the sample size was 99 %. Medical history, as well as obstetric and perinatal characteristics, were analyzed, stratifying the study sample into primigravidae and multigravidae. Odds ratios (OR) and 95 % confidence intervals (CI) were estimated with a binary logistic model for each stratum. A p-value < 0.05 was considered significant.

There were 476 cases and 976 controls. Female fetal sex was not associated with preeclampsia, adjusting for confounding variables (primigravidae: OR 1.32 [95% CI 0.84, 2.09]; multigravidae: OR 0.90 [95% CI 0.65, 1.23]).

No association was found between fetal sex and preeclampsia in women from northeastern Mexico, stratified by parity status, and after controlling for multiple confounders. Future studies should consider stratification by parity to investigate the risk of preeclampsia.