Factors influencing pulmonary surfactant protein A levels in cord blood, maternal blood and amniotic fluid.

The purpose of this study was to evaluate factors that influence pulmonary surfactant protein A (SP-A) levels in cord blood, maternal blood and amniotic fluid, as well as to establish the normal range of serum SP-A. Labor significantly influenced cord blood SP-A levels. The SP-A levels in maternal blood after delivery were correlated with, but higher than those before delivery. There was a correlation between SP-A levels in amniotic fluid and cord blood. Neonatal serum SP-A was not correlated with maternal SP-A levels. The normal range of SP-A in cord blood was 2.7-21.7 ng/ml following cesarean section without labor, 4.8-50.2 ng/ml after labor at gestational weeks 36-38, and 12.2-44.6 ng/ml at gestational weeks 39-41. SP-A levels in maternal blood before and after delivery and amniotic fluid were 6. 0-74.0, 9.6-73.6 and 403.4-24,540 ng/ml, respectively.