Smoking, alpha 1-antitrypsin and decreased fertility in women

There is epidemiologic evidence that smoking by women is associated with decreased fertility. Little is known about the biological mechanism(s) that might underlie a direct association. The effect of smoking on genital secretions, including levels of alpha 1-antitrypsin (AlAT), has not been studied. Low midcycle levels of AlAT appear to favour fertility by facilitating sperm migration and/or penetration. Smoking increases serum levels of functional AlAT. Since AlAT is produced only in the liver, levels in other tissues may reflect serum levels. It is postulated that smoking-induced increases in serum AlAT result in higher levels of AlAT in genital secretions, including those at midcycle, thereby impeding fertility. Support of an effect of serum AlAT levels on fertility is provided by studies of AlAT deficient persons, in whom fertility seems to be enhanced. An adverse effect of smoking on fertility through an increase in genital tract AlAT levels would be reversible.