Effect of maternal risk factors and placental histopathology on neonatal morbidity in late preterm infants

Dutucu A, Effect of maternal risk factors and placental histopathology on neonatal morbidity in late preterm infants. Baskent University, Faculty of Medicine, Department of Pediatrics, Thesis, Ankara, 2018. Preterm births are the most important risk factor for neonatal morbidity and mortality. All infants born before 37 gestational weeks are defined as preterm. About 65-70% of these babies are late preterm infants who were born between 340/7- 366/7 gestational weeks. Late preterm infants are often considered to be mature functionally and developmentally, they were also considered as full-term babies. Therefore, these problems can be overlooked in late preterm infants. This study was carried out between January 2018 and July 2018 at Baskent University Faculty of Medicine including a total of 62 late preterm infants. We evaluated neonatal morbidities in these infants according to placental pathology and maternal risk factors. Multiple congenital anomalies, chromosomal abnormalities and late preterm newborns who were born at the other hospitals were excluded from the study. The most frequent morbidities were feeding intolerance (56.5%), hyperbilirubinemia (50%), hypoglycemia (32.3%), neonatal transient tachypnea (16.1%), polycythemia (9.7%), sepsis (8.1%) and respiratory distress syndrome (6.5%). When we compared according to gestational weeks (34th, 35th and 36th weeks) of late preterm infants; the length of hospitalization, morbidities and treatment requirement were found to be highest in 34th weeks of gestation. Maternal malperfusion pathology in the placenta was related to hyperbilirubinemia and intracranial hemorrhage; chronic inflammation pathology was related to polycythemia, feeding intolerance and recurrent hospitalization; fetal obliterative vasculopathy pathology was related to polycythemia; placentomegaly was related to early neonatal sepsis and feeding intolerance; placental hematomas were related to pneumothorax that all were found to be statistically significant. The following diseases were observed more frequently in the presence of these maternal risk factors, respectively. These included hyperbilirubinemia and feeding intolerance which were mostly observed in infants of preeclamptic mothers; also feeding intolerance in infants of mothers who have PPROM; hyperbilirubinemia and feeding intolerance in infants of oligohydramniotic mothers; RDS and intracranial hemorrhage in infants of mothers with placenta previa; hyperbilirubinemia, early neonatal sepsis and feeding intolerance in infants of mothers with maternal thrombophilia and early neonatal sepsis and re-hospitalization in infants of mothers with maternal infections that were found to be statistically significant. Consequently; in our study, the babies who were born at the 34th gestational weeks have more morbidities than the late preterm infants born in other gestational weeks. It has been determined that risk factors such as preeclampsia, oligohydramnios, thrombophilia, infection and placental problems such as maternal malperfusion, chronic inflammation and placentomegaly increase morbidities in late preterm infants. Keywords: late preterm, morbidity, placental pathology, maternal risk factors