Violence has been chronicled in from 6% to 20% of pregnancies, depending partly on how it is defined. The possibility of serious consequences from prenatal violence prompted a prospective cohort study enrolling women who,during a 2-year period in 1994-1996, took part in a maternity care coordination program. Three times the women were asked if they had been hit, slapped, kicked, or hort during the current pregnancy. All those revolting violence were counseled and offered domestic violence shelter and services. Of 550 participants, 13.5% reported violence, which was rated as severe in half the cases (hitting, kicking, injury by a weapon, abdominal injury) and moderate in the remaining half (threats, slapping, shoving, sexual abuse). Hitting and kicking were the commonest forms of violence, and most often the violator was a partner or ex-partner. Although the face and head were the most common targets, many women reported abdominal injury. The average number of violent incidents reported was 1.5. Younger women, the unmarried, and those with little education more often reported severe physical violence. The same was the case for primiparas and African American women. In addition, women reporting severe physical violence were significantly likelier to have a previous perinatal death or preterm birth or to have used alcohol in the current pregnancy. The apparent relationship between severe violence and preterm labor or delivery, very low birth weight, low Apgar scores, and neonatal intensive care persisted after controlling for age, race, a previous poor birth outcome, and alcohol use. Seven of 13 women reporting prenatal violence directed at the abdomen delivered before term, and 5 had a low birth-weight infant. Prenatal physical abuse clearly is associated with preterm delivery, especially when directed at the abdomen. The findings point to a need to routinely screen for such violence. Women subjected to violence should be closely watched for preterm labor.