Smoking in pregnancy in relation to gender and adult mortality risk in offspring: The Helsingborg Birth Cohort Study

Background: Smoking in pregnancy is a well-documented risk factor for fetal growth impairment and poor perinatal outcomes. Less is known about the long-term effects of maternal smoking on offspring mortality. Methods: A follow-up study in national registers on total mortality and cancer based on a birth cohort from Helsingborg, Sweden, including data on 2,010 sons and 1,982 daughters born to mothers for whom the smoking habits during pregnancy (50% smokers) have been recorded. Results: A total of 92 offspring deaths were recorded (54 men, 38 women) during follow-up. Of these deaths, 43 deaths were related to trauma, 6 to circulatory disease, and 2 to endocrine disorders. In men, an elevated mortality risk was associated with increasing maternal smoking habits (p for trend 0.011), but in women with low birth weight (p for trend 0.006). A total of 47 incident offspring cancers were registered (18 in men and 29 in women). No significant relation was noted for maternal smoking habits and cancer in the offspring. Conclusions: Maternal smoking during pregnancy is associated with an increased mortality risk in early adult life for male offspring but not for female offspring. This could represent the possible consequence of an increased susceptibility in male fetuses.