Objective: To investigate the association between gender and birth trauma in full-term infants.
Methods: A retrospective, cohort, case-control study was conducted. All singleton full-term neonates born in 1986-2009 and diagnosed with birth trauma (ICD9-CM codes 767.0-767.9) were identified from the hospital's computerized birth-discharge records. The study group was matched in a 2:1 ration with neonates delivered immediately after each index case of neonatal trauma.
Results: Of the 118, 280 singleton full-term infants delivered during the study period, 2876 (24/1000) experienced birth trauma. The most frequent birth traumas were scalp injury (63.9%) and clavicle fracture (32.1%). The overall risk of birth trauma was unrelated to fetal gender. However, fetal male gender was a significant and independent risk factor for scalp injury (OR=1.31, 95%-CI 1.15-1.49), and female fetal gender was a significant and independent risk factor for clavicle fracture (OR=1.27, 95%-CI 1.09-1.49). The significance of these associations persisted even after adjustment for potential confounders including mode of delivery, gestational age, neonatal length, timing of delivery, head circumference, parity, and birth weight.
Conclusion: Fetal gender appears to be a predisposing risk factor for specific types of birth trauma. Further studies are needed to investigate the reasons for this observation.