WEIGHT-GAIN ASSOCIATED WITH PRENATAL SMOKING CESSATION IN WHITE, NON-HISPANIC WOMEN

OBJECTIVE: Our purpose was to assess the effect of prenatal smoking ce ssation on maternal weight gain and infant birth weight in women who s moked at least five cigarettes per week. STUDY DESIGN: This prospectiv e study followed up a sample of white, non-Hispanic pregnant smokers e nrolled in three multispecialty clinics. By use of t tests, women quit ting smoking before 28 weeks and continuing smokers were compared on t otal weight gain, Institute of Medicine weight gain categories, and in fant birth weight. RESULTS: Quitters gained 36.6 pounds (SD 14.5) and smokers 28.9 pounds (SD 11.7) lo < 0.001). The relative risk of quitte rs gaining less than the Institute of Medicine minimum was 0.47 (95% c onfidence interval 0.27 to 0.81). Quitters also gained more than Insti tute of Medicine standards (relative risk 1.74, 95% confidence interva l 1.21 to 2.51), and they were 3.1 times as likely to be delivered of infants weighing >4000 gm (95% confidence interval 1.18 to 7.97). The four low-birth-weight babies were born to smokers with low weight gain . CONCLUSION: In this population smoking cessation is associated with a lower risk of gaining too little by Institute of Medicine standards and also with higher risk of gaining more than the Institute of Medici ne standard and having infants weighing >4000 gm. The clinical signifi cance of these effects needs to be determined in further studies.