Factors associated with spontaneous and iatrogenic preterm birth in Kazakhstan: implications for subtype–specific surveillance and prevention

Background Preterm birth (PTB) remains a leading cause of neonatal morbidity and mortality worldwide. Distinguishing spontaneous preterm birth (SPB) from iatrogenic preterm birth (IPB) is important because these subtypes differ in their clinical characteristics and may require different surveillance and prevention strategies.Objective To compare maternal characteristics, factors associated with PTB subtype, and neonatal outcomes between spontaneous and iatrogenic preterm births in Kazakhstan.Methods We conducted a retrospective comparative study of 1,000 women with preterm birth between 22 + 0 and 36 + 6 weeks of gestation at a tertiary referral center in Almaty, Kazakhstan, during 2021–2022. Maternal, obstetric, and neonatal data were extracted from electronic medical records. Univariable and multivariable logistic regression analyses were performed to identify maternal and obstetric characteristics associated with IPB versus SPB.Results Among 1,000 preterm births, 588 (58.8%) were spontaneous and 412 (41.2%) were iatrogenic. Hypertensive disorders of pregnancy (aOR 6.70, 95% CI 4.84–9.27), oligohydramnios (aOR 3.51, 95% CI 1.94–6.35), coagulopathies (aOR 3.32, 95% CI 1.85–5.97), fetal growth restriction (aOR 2.60, 95% CI 1.53–4.50), and anemia (aOR 1.46, 95% CI 1.09–1.96) were more frequently associated with IPB, whereas cervical insufficiency was more strongly associated with SPB (aOR 0.34, 95% CI 0.20–0.60). Neonates in the IPB group had lower birth weight and Apgar scores than those in the SPB group.Conclusions SPB and IPB demonstrated distinct maternal, obstetric, and neonatal profiles. These findings support subtype-specific surveillance strategies integrating prevention of spontaneous preterm birth with early recognition and management of maternal and placental disorders leading to medically indicated preterm birth.