Although the prevalence of alcohol, tobacco, and illicit drug use among women is lower than that among men, women suffer unique adverse health effects from these substances. Furthermore, the use of these substances during pregnancy poses special risks to mother and fetus, including placental accidents, intrauterine growth retardation, congenital anomalies, and premature birth. Primary care clinicians should ask all women about their patterns of alcohol, tobacco, and illicit drug use and should offer targeted interventions to those using these products.