The use of osteopathic manipulative treatment (OMT) during pregnancy has a long tradition in osteopathic medicine. A retrospective study was designed to compare a group of women who received prenatal OMT with a matched group that did not receive prenatal OMT. The medical records of 160 women from four cities who received prenatal OMT were reviewed for the occurrence of meconium-stained amniotic fluid, preterm delivery, use of forceps, and cesarean delivery. The randomly selected records of 161 women who were from the same cities, but who did not receive prenatal OMT, were reviewed for the same outcomes. The results of a logistic regression analysis were statistically reliable, chi2 (4, N = 321) = 26.55; P < .001, indicating that the labor and delivery outcomes, as a set, were associated with whether OMT was administered during pregnancy. According to the Wald criterion, prenatal OMT was significantly associated with meconium-stained amniotic fluid (Z = 13.20, P < .001) and preterm delivery (Z = 9.91; P < .01), while the use of forceps was found to be marginally significant (Z = 3.28; P = .07). The case control study found evidence of improved outcomes in labor and delivery for women who received prenatal OMT, compared with women who did not. A prospective study is proposed as the next step in evaluating the effects of prenatal OMT.