RESUMO
OBJECTIVE: To investigate fetal gender and its influences on neonatal outcomes, taking into consideration the available tools for the assessment of fetal well-being. METHODS: We conducted a retrospective study comparing maternal, fetal and neonatal outcomes according to fetal gender, in women carrying a singleton gestation. A multivariate analysis was performed for the prediction of adverse neonatal outcomes according to fetal gender, after adjustment for gestational age, maternal age and fetal weight. RESULTS: A total of 682 pregnancies were included in the study, of them 56% (n = 383) were carrying a male fetus and 44% (n = 299) a females fetus. Male gender was associated with a significant higher rate of abnormal fetal heart tracing patterns during the first (67.7% versus 55.1, p = 0.001) and the second stage (77.6 versus 67.7, p = 0.01) of labor. Male gender was also significantly associated with lower Apgar scores at 1' (19.1% versus 10.7%, p < 0.01), as well as lower pH values (7.18 ± 0.15 versus 7.23 ± 0.18, p < 0.001), and significant differences in cord blood components (PCO2, PO2) compared with female fetuses. In the multivariate analysis, male gender was found to be significantly associated with first (OR 1.76, 95% CI 1.28-2.43, p = 0.001) and second stage (OR 1.73, 95% CI 1.20-2.50, p < 0.01) pathological fetal heart tracing patterns, pH < 7.1, and for Apgar scores at 1'< 7. CONCLUSIONS: The present study confirms the general trend of a lower clinical performance of male neonates compared with females. In addition, the relation between fetal heart rate patterns during all stages of labor and fetal gender showed an independent association between male fetal gender and abnormal fetal heart monitoring during labor.
