Determinants of spontaneous and iatrogenic preterm birth in Kazakhstan: a retrospective cohort study

Background Preterm birth (PTB) is a leading cause of neonatal morbidity and mortality, with distinct etiologies for spontaneous (SPB) and iatrogenic (IPB) subtypes. Comparative evidence on maternal risk factors and neonatal outcomes for these groups remains limited. Objective To compare maternal risk factors and neonatal outcomes between spontaneous and iatrogenic preterm births. Study Design: We conducted a retrospective cohort study of 1,000 women who delivered preterm infants (22–36 + 7 weeks) at a tertiary perinatal center between 2021 and 2022. Data from electronic medical records were analyzed using nonparametric tests and multivariable logistic regression. Primary outcomes included maternal risk factors and neonatal outcomes. Results Of all PTB cases, 58.8% were spontaneous and 41.2% iatrogenic. Among SPB, 53.0% followed spontaneous labor and 46.9% were associated with premature rupture of membranes. Neonates in the IPB group had significantly lower birth weight, length, and Apgar scores (p < 0.001), although neonatal morbidity and mortality did not differ. Logistic regression showed that IPB was associated with hypertensive disorders (aOR 6.7, 95% CI 4.84–9.27), fetal growth restriction (aOR 2.60, 95% CI 1.53–4.50), anemia, coagulopathies, oligohydramnios, and IVF, while SPB was linked to cervical insufficiency. Conclusion Spontaneous and iatrogenic PTB represent distinct entities with different maternal risk profiles but similar neonatal outcomes. While cervical insufficiency remains the established risk factor for SPB, the growing contribution of IPB underscores the need for strict evidence-based justification of medically indicated preterm deliveries.