Perinatal and Early Respiratory Factors Associated with Invasive Mechanical Ventilation in Very Preterm Infants: A Retrospective Cohort Study from Kazakhstan

Background: Evidence on factors associated with the timing of invasive mechanical ventilation (IMV) among very preterm infants in Central Asia remains limited. Methods: This retrospective cohort study included infants born at 22–30 weeks gestation in two tertiary perinatal centers in Kazakhstan between 2021 and 2025. Analyses were restricted to 381 infants with complete data. IMV initiated during the first week of life was classified as early IMV, and IMV initiated after the first week as late IMV. Separate multivariable logistic regression models were constructed for any, early, and late IMV. Results: Any IMV was recorded in 191 infants (50.1%), including 132 (34.6%) with early IMV and 59 (15.5%) with late IMV. Early IMV was associated with gestational age ≤ 27 weeks (aOR 3.91, 95% CI 1.66–9.22), absence of spontaneous breathing at birth (aOR 151.93, 95% CI 18.26–1263.88), and initial FiO2 > 0.30 (aOR 4.39, 95% CI 1.97–9.77). Complete antenatal corticosteroid exposure was inversely associated with early IMV (aOR 0.38, 95% CI 0.20–0.72). Late IMV was associated with birth weight < 1000 g (aOR 3.51, 95% CI 1.47–8.35) and initial FiO2 > 0.30 (aOR 2.12, 95% CI 1.02–4.39). An initial set CPAP ≥ 12 cmH2O was recorded in 71.9% of infants and was associated with any IMV but not with early or late IMV separately. Conclusions: Early and late IMV were associated with different clinical patterns. These observational associations may support risk assessment but do not establish causal effects of respiratory-support practices.