January 3, 1986

Smoking, Sex, and Pregnancy

Author Affiliations

Family Health International Research Triangle Park, NC

JAMA. 1986;255(1):35. doi:10.1001/jama.1986.03370010037007

To the Editor.—  In their article demonstrating reduced fecundity among women smokers, Baird and Wilcox1 cite two other articles that demonstrated a similar effect, and four that failed to do so; other "negative" studies may remain unpublished because of reluctance to report such work. Another recent article is also consistent with their findings.2 The degree of decrease of fecundity in their study, 28%, as compared with that of non-smokers, may overestimate the magnitude of effect for two reasons.First, the time to conceive used by the authors may have been artifactually lengthened by their considering sporadic use of contraceptives as half cycles, with rounding down to the nearest full cycle. Since smokers used contraceptives sporadically 1.5 times as often as nonsmokers, this treatment would lengthen the interval to conception differentially for the smokers. Second, only women seeking prenatal services were included. Thus, women with early spontaneous abortions, which are