Comparative Study on Umbilical Cord Serum Prolactin Levels of Normal Preterm Neonates and Preterm Neonates with Respiratory Distress Syndrome

Abstract

Introduction: Respiratory distress syndrome (RDS) is the most common cause of respiratory distress, morbidity, and mortality associated with premature delivery. Prolactin is present in very high concentrations in amniotic fluid, and prolactin receptors are present in lung preparations. Prolactin acts as a direct trigger of lecithin synthesis or in a “chain reaction” along the hypothalamic–pituitary–adrenal axis. Thus, prolactin seems to have a role in lung maturation along with many other factors through a complex mechanism. Aim: The aim of this study was to evaluate and compare the umbilical cord serum prolactin levels of preterm infants with and without RDS. Materials and Methods: This was a hospital-based comparative observational study carried out at neonatal units of the department of pediatric medicine in a tertiary care center from April 2019 to May 2020. Out of a total of 80 preterm infants, 40 developed RDS and other 40 served as controls. Umbilical cord blood prolactin levels in neonates were measured in both groups and compared. Chi-square test and an unpaired Student’s t-test were used for statistical analysis. Probability was considered significant if <0.05. Results: The mean weight of babies was 1312.50 ± 134.30 g in the normal preterm group and 1285.80 ± 314.76 g in the preterm RDS group (P = 0.622). The mean gestational age was 32.1 ± 1.39 weeks in the normal preterm group and 31.77 ± 2.10 weeks in the preterm RDS group (P = 0.418). The mean serum prolactin levels were slightly high in the female preterm RDS group (P = 0.533). The mean cord prolactin levels in all the gestational ages were higher in normal preterm as compared to preterm with RDS (P < 0.05). Conclusions: Prolactin level was significantly associated with gestational age and birth weight. Low prolactin levels were significantly associated with the development of RDS in preterm babies. The easily available cord blood can be used to measure prolactin levels at birth to predict RDS.