Nicotine patch use in pregnant smokers: Nicotine and cotinine levels and fetal effects

OBJECTIVE: The aims of this study were (1) to determine whether nicotine pa tch therapy for pregnant women smokers acutely compromises fetal well-being and (2) to determine the serum and urine nicotine and cotinine levels in p regnant women while smoking, while abstinent from smoking, and while receiv ing nicotine patch therapy compared with levels in a historical control gro up of nonpregnant women smokers who abstained from smoking while receiving comparable doses of nicotine patch therapy. STUDY DESIGN: Pregnant cigarette smokers (n = 21) aged greater than or equa l to 18 years whose fetuses were beyond 24 weeks' gestational age were recr uited for this 1-sample, repeated-measures study. Serial measurements of th e mother and fetus were made at baseline while the mother was smoking, whil e abstaining from smoking, and while using nicotine patch therapy for 4 day s in a special care hospital unit. Nonpregnant women smokers of similar age were used for comparison. Morning and afternoon serum and 24-hour urine le vels of nicotine and cotinine were obtained during hospitalization. Indicat ors of fetal well-being assessed were fetal heart rate and reactivity, syst olic/diastolic ratio of blood flow in the umbilical artery, and fetal activ ity seen on ultrasonography and quantitated as biophysical profiles. RESULTS: No evidence of fetal compromise was seen during the inpatient phas e while nicotine patch therapy was administered. Steady state (inpatient da y 4) serum levels of nicotine were similar to smoking levels and to those s een in historical control subjects (ie, nonpregnant women of child-bearing age who were abstinent from smoking and who used the same nicotine patch). Morning serum cotinine levels were significantly higher (P = .038) in the n onpregnant subjects than in the pregnant subjects, whereas afternoon levels were not significantly different. Steady state urinary levels of nicotine and cotinine were also not significantly different in pregnant versus nonpr egnant patients. On inpatient days 2, 3, and 4, when the women were not smo king and were wearing the nicotine patch, the morning fetal heart rates wer e significantly reduced relative to baseline when the subjects were smoking . CONCLUSIONS: Nicotine patch therapy was not found to be associated with ind ications of fetal compromise during the in-hospital phase of nicotine patch therapy in pregnant smokers who were abstaining. Although not conclusive b ecause of the small sample sizes, serum nicotine levels (morning and aftern oon) appear similar in pregnant and nonpregnant subjects and similar for bo th groups when smoking (baseline) as compared to the steady state of nicoti ne patch use.