Causes of low birth weight births in public and private patients.

This examination of the cause of low birth weight births in two model populations, one of public and one of private patients, finds significant differences in the reasons for low birth weight births in the two groups. Idiopathic premature labor was related to 47.1% of private low birth weight births, but only 24.8% of public births; low birth weight term (26.7%) and premature rupture of fetal membranes (33.7%) were more common in public low birth weight births than in private births (13.8% and 23.0%, respectively). Medical problems were related to 16.1% of private and 14.9% of public low birth weight births. Since current prematurity prevention methods are most likely to prevent low birth weight births related to idiopathic premature labor, the relative success of such programs in reducing the rate of low birth weight births is likely to depend on the characteristics of the patient population to which the programs are directed.