Ginekol Pol. 2026;97(6):466-485. doi: 10.5603/gpl.109312.
ABSTRACT
OBJECTIVES: Fetal and placental growth are influenced by multiple maternal and fetal factors, including fetal sex and maternal parity. Accurate knowledge of these determinants is essential for growth monitoring and perinatal risk assessment. This study aimed to evaluate the effects of fetal sex and maternal parity on birth weight, placental weight, and the fetal-to-placental weight ratio in a large single-center cohort.
MATERIAL AND METHODS: We conducted a retrospective cohort study of 4,642 singleton live births between 28 and 40 weeks of gestation at a tertiary hospital in the Wielkopolska region, Poland. Birth weight, placental weight, and fetal-to-placental weight ratios were analyzed according to fetal sex and maternal parity. Percentile charts were generated, and differences were assessed using appropriate statistical tests with p < 0.05 considered significant.
RESULTS: Male newborns had higher birth weights than females, with significant differences from 36 to 40 weeks. Placental weight increased with gestational age, with males showing higher values at 38-40 weeks. Fetal-to-placental weight ratios were higher in males at 30, 36, 37, and 40 weeks, indicating greater placental efficiency. Multiparous women delivered newborns with higher birth and placental weights compared to primiparas, particularly in late gestation. Correspondingly, fetal-to-placental ratios were higher among multiparas, reflecting enhanced placental efficiency in subsequent pregnancies.
CONCLUSIONS: Fetal sex and maternal parity significantly influence fetal and placental growth and fetoplacental efficiency. Male newborns and offspring of multiparas had higher birth weights and more favorable fetal-to-placental weight ratios. The provided percentile charts may serve as practical references for obstetric and neonatal care in the Wielkopolska region.
PMID:42522555 | DOI:10.5603/gpl.109312
