Analysis of risk factors of late preterm birth: A case-control study

Abstract

Objective: The aim of this study is to identify the risk factors associated with late preterm births (LPBs). Methodology: This case-control study was conducted in the Department of Obstetrics and Gynecology, teaching hospital attached to KLE University's Jawaharlal Nehru Medical College, Belagavi during May 2015–April 2016. A total of 918 women were enrolled into the study, 459 in each group. Women who delivered between 34 and 36 weeks 6 days were considered cases and controls were women who delivered from 37 weeks onward immediately after a case occurred. Gestational age was confirmed with ultrasonography before 20 weeks. Data were collected from the history of the patient and the medical records. Results: Incidence of LPB was found to be 8% among total births. It was found that 55.1% were spontaneous births. The most common risk factor for LPB was hypertensive disorders of pregnancy (gestational hypertension [HTN]–4.8%, chronic HTN–5%, preeclampsia–36%, eclampsia–4.8%) followed by preterm premature rupture of membranes (32.7%), history of prior preterm births (19.2%), gestational diabetes (17.9%), multifetal gestation (16.6%), placenta previa (13.5%), and abruption placenta (9.8%). On analyzing neonatal outcome, sepsis was found in 25%, hyperbilirubinemia in 21.9%, respiratory distress syndrome in 19%, transient tachypnea of newborn in 9%, and patent ductus arteriosus in 2.9% of the neonates. Conclusion: The indication for the induction or need for termination should be reevaluated in the late preterm gestation. To prevent LPB, identification of the risk factors is necessary and timing of delivery in each risk factor should be reassessed in advance before intended intervention. As LPB constitute the majority of preterm births, it is important to limit late preterm deliveries to clear maternal or fetal indication for delivery.