Risk factors for extremely preterm and very preterm birth

Aim. To evaluate the prevalence of preterm birth and risk factors for extremely preterm, very preterm, and moderate to late preterm birth.Materials and Methods. We retrospectively assessed case histories of 11,500 pregnant women delivered in Kuzbass Regional Children's Clinical Hospital during 2019-2021 and their newborns. Among the studied factors were gestational age, birth weight, sex, 5-minute Apgar score, maternal age (< 20 years, 20-35 years, ≥ 35 years), parity (primiparity or multiparity), active smoking, maternal diseases during pregnancy (gestational hypertension, intrahepatic cholestasis of pregnancy, gestational diabetes mellitus, anemia, gastrointestinal and genitourinary diseases), chorioamnionitis, and pregnancy complications (placental abruption, placenta previa, vaginal bleeding, polyhydramnios), fetal distress, and fetal growth restriction.Results. Prevalence of preterm birth was 8.4%. The potential risk factors for preterm birth were placental abruption, placenta previa, short (< 25 mm) cervix, intrahepatic cholestasis of pregnancy, gestational hypertension, chorioamnionitis, anemia, young (< 20 years) and advanced (≥ 35 years) maternal age, primiparity, active smoking, and fetal distress. Among them, placental abruption, placenta previa, short (< 25 mm) cervix, gestational hypertension, and chorioamnionitis were specific risk factors of extremely preterm and very preterm birth whilst intrahepatic cholestasis of pregnancy was the risk factor of moderate to late preterm birth.Conclusion. Extremely preterm, very preterm, and moderate to late preterm birth have distinct risk factor profiles, highlighting the need for differential pregnancy management strategies.