Predictors of very preterm births (born between 23 and 29 weeks’ gestation) at a tertiary care center in Karachi, Pakistan: additional multivariate analyses on data from primary cohort

Previously, we have published univariate analyses on a cohort of all singleton, very preterm infants (N = 101) born between 23 and 29 weeks of gestation during January 01, 1998 to June 30, 2003 at The Aga Khan University Hospital in Karachi, Pakistan. Our main objective was to extend these analyses to multivariate logistic regression models and report odds ratios (ORs) for univariate and multivariate analyses. All variables in univariate were included in multivariate models. The survival incidences were 0% at 23, 16.7% at 24, 40.0% at 25, 30.0% at 26, 33.3% at 27, 68.8% at 28 and 83.9% at 29 weeks of gestation. In univariate analyses, gestational age, birth-weight and mode of delivery (cesarean-section had higher survival compared to vaginal) were statistically significant predictors of survival (P [less than or equai to] 0.001 each). Other variables that also included antenatal steroids did not achieve significance. However, in complete-case multivariate analyses, only gestational age (per week) was associated with survival (OR = 2.5, 95% CI 1.1-5.5, P = 0.03); birth-weight (per 100 g) and C-section were not associated-1.2, 0.88-1.6, P = 0.26 and 2.4, 0.48-12.2, P = 0.28. Antenatal steroid use, maternal age, year of birth, parity, history of preterm delivery, hemoglobin levels, complications and time of birth remained not associated.