Objective: The aim of this national population-based study was to identify perinatal and neonatal factors associated with active intensive treatment (AIT) of infants born at the periviable period of 22 to 24 weeks of gestation.
Study design: Data from the Israel national very low-birth weight infant database on 2207 infants born alive in 1995 to 2010 at gestational age (GA) 22 to 24 weeks were evaluated. AIT was defined as endotracheal intubation in the delivery room or mechanical ventilation in the neonatal intensive care unit. Multivariable logistic regression analyses were used to identify the independent effect of demographic and perinatal factors on AIT for each gestational week.
Result: Of the 2207 infants born at 22 to 24 weeks GA, 1643 (74.4%) received AIT and 564 (25.6%) received comfort care. AIT increased from 25.5% at 22 weeks to 62.7 and 93.5% at 23 and 24 weeks GA, respectively, reflecting a 4.66 (95% confidence interval (CI) 3.32 to 6.54)- and 29.8 (95% CI 19.9 to 44.6)-fold odds for AIT at 23 and 24 weeks GA, respectively, compared with 22-week GA infants. Perinatal treatments associated with AIT included maternal tocolytic therapy (odds ratio (OR) 1.51, 95% CI 1.04 to 2.20), prenatal steroid therapy, both partial (OR 3.30, 95% CI 2.14 to 5.10) and complete (OR 3.17, 95% CI 1.91 to 5.26) and cesarean delivery (OR 2.68, 95% CI 1.88 to 3.83). Each unit increase in birth weight z-score was associated with an OR of 1.58 (95% CI 1.30 to 1.92) for AIT. At 22 weeks GA, maternal tocolytic treatment was associated with higher odds of AIT. In the 23 and 24-week GA infants, maternal infertility treatment, antenatal steroids, cesarean delivery and higher-birth weight z-scores were significantly associated with AIT. Among 23-week GA infants, AIT decreased significantly in the period 2006 to 2010 compared with 1995 to 2000 (OR 0.51, 95% CI 0.34 to 0.77).
Conclusion: An active approach in obstetric management of pregnancies appears to impact the neonatologists' decision to undertake AIT treatment in infants born at the border of viability. The higher odds for AIT associated with obstetric interventions might contribute to the reported beneficial effect of antenatal steroids and cesarean delivery on the survival of infants born at the border of viability.