Changing obstetric practice and 2-year outcome of the fetus of birth weight under 1000 g.

The aim of this study was to assess the outcome up to 2 years of age for the fetus of birth weight 500-999 g, over time and in association with changes in obstetric care. Two consecutive cohorts of infants of birth weight 500-999 g were compared from two eras, 1977-1982 and 1985-1987, and their outcome up to 2 years of age was determined with particular emphasis on the effect of various obstetric interventions at the time of birth, such as cesarean delivery, electronic fetal monitoring, antenatal steroid therapy, and tocolytic therapy. The outcome to 2 years was analyzed by logistic function regression to adjust for imbalances in confounding perinatal variables. In the latter era, the survival rate to 2 years increased significantly by almost 50%, and only 7% of the survivors were severely disabled. The rates of delivery by cesarean and of electronic fetal monitoring both increased significantly in the latter era, but neither was associated with the improved outcome. The only variable associated with an improved outcome that was amenable to obstetric intervention at the time of birth was antenatal steroid therapy, which was used equally in both eras. The obstetrician may aid the fetus of birth weight 500-999 g by giving the mother steroids to accelerate fetal lung maturity, but cesarean cannot be recommended as the routine mode of delivery unless there are recognized maternal or fetal indications.