Metabolism of Nicotine and Cotinine in Pregnant African-American Women

This study will provide information regarding the optimal dose and duration of nicotine replacement using the nicotine patch for a smoking cessation study of pregnant African-American women. Previous studies have shown that pregnancy, race and ethnicity can affect the way people metabolize nicotine. The information from this study may help scientists develop ways to help pregnant African-American women quit smoking and not start smoking again after delivery. African-American women 18-30years of age who are in the second trimester of a healthy pregnancy, who are carrying only one baby and who smoke 10 or more cigarettes a day may be eligible for this study. Candidates are screened with a medical history, physical examination and urine test. They receive counseling to help them quit smoking. Those who cannot quit smoking within 7 to 10 days after receiving counseling may be invited to join the study. Participants are admitted to a private room in the Pediatric Clinical Research Center at Children's National Medical Center in Washington, D.C., for 48 hours, during which time they are not permitted to smoke. After a "wash out" period, a nicotine patch will be applied according to these doses and schedules: * 21 mg patch for 24 hours * 21 mg patch for 16 hours * 14 mg patch for 24 hours * 14 mg patch for 16 hours An intravenous (IV) line is placed in the subject's arm and 12 blood samples are drawn through the line at intervals during the 48 hours. Twleve urine and saliva samples are also collected. Blood, urine, and saliva samples are analyzed for nicotine and cotinine (a product of nicotine metabolism) levels, and DNA will be collected studied for genes that are associated with nicotine and cotinine metabolism. Participants are interviewed about their urges to smoke, quality of sleep, etc.