Objective: To identify the frequency and maternal and neonatal factors associated with meconium-stained amniotic fluid at birth.
Methods: Cross-sectional study carried out with 2,441 births at an in-hospital birth center in the city of São Paulo (Southeastern Brazil) in March and April, 2005. The association between meconium-stained amniotic fluid and the independent variables (maternal age, parity, previous c-section or not, gestational age, obstetric history, oxytocin use in the labor, cervical dilation at admission, mode of current delivery, newborn weight, Apgar score at the 1st and 5th minute) was expressed as prevalence ratio (PR).
Results: Meconium-stained amniotic fluid was verified in 11.9% of the births; 68.2% of these were normal births and 38.8% c-sections. Meconium was associated with: primiparity (PR=1.49, 95%CI 1.29; 1.73), gestational age ≥ 41 weeks (PR = 5.05, 95%CI 1.93;13.25), oxytocin in labor (PR = 1.83, 95%CI 1.60; 2.10), c- section (PR = 2.65, 95%CI 2.17; 3.24) and Apgar scores < 7 at the 5th minute (PR = 2.96, 95%CI 2,94;2,99). Neonatal mortality was 1.6/1,000 live births. Meconium-stained amniotic fluid was found in 50% of neonatal deaths and it was associated with higher rates of surgical deliveries.
Conclusions: Oxytocin use, worse conditions of the newborn after the delivery and increased c-section rates were factors associated with meconium-stained amniotic fluid. Routine use of oxytocin in the intrapartum period could be evaluated due to its association with meconium-stained amniotic fluid.