The objective of this study was to assess whether duration rather than quantity or frequency of maternal smoking during pregnancy significantly accounted for the explained variance in birth weight. The study was a prospective descriptive study using a convenience sample. The study took place in two prenatal clinics located in two mid-Atlantic inner-city teaching hospitals. Participants were 165 maternal-infant pairs. The main outcome measures were birth weights adjusted for baby's sex, race, and length of gestation. Fifty-seven (34.6%) of the mothers reported a history of smoking prior to pregnancy. Of these, 40 continued to smoke during pregnancy. A significantly larger proportion of smoking mothers had infants in the 10th percentile for birth weight (z = -2.965; p < 0.003). The overall regression model was significant, and the only significant predictor of birth weight was duration of maternal smoking during pregnancy (R = 0.237; F[1.1631 = 9.723; p < 0.01). Initial prenatal assessments must include a history of maternal smoking. For mothers identified as smokers, nursing interventions should include smoking cessation programs as early as the first prenatal visit. Furthermore, since pregnancy recognition normally occurs at or after 6 weeks, prevention efforts should focus on smoking cessation programs for women throughout their childbearing years.
(C) 1999International Nurses Society on Addictions