“…In 1966, Abramowicz and Kass concluded that the published evidence supporting a positive relation between prenatal care and birthweight was inconclusive.2 Using data from the 1972 National Natality Survey, Placek found that absence of prenatal care was associated with low birthweight.3 Studying birth certificate data, Taffel found that a higher number of prenatal visits was associated with normal birthweight, but that mother's education and ethnic group were more important than the timing of the onset of prenatal care in determining low birthweight.4,5 By studying 130,000 births in upstate New York in 1973, Stickle and Ma found that prenatal care that started in the first trimester was associated with better pregnancy outcome. 6 Gortmaker studied vital statistics records for all births in New York City in 1968. 7 He found that-after controlling for a variety of factors, including parent's education, maternal age, length of gestation and adequacy of prenatal care based on Institute of Medicine criteria8-adequate prenatal care was associated with higher birthweights.…”