Cryptorchidism according to maternal gestational smoking

BACKGROUND: It has been suggested that maternal smoking during pregnancy is a risk factor for low sperm counts and testicular cancer in the offspring. Cryptorchidism is associated with both of these disorders and might share causal mechanisms. METHODS: We used prospective information on prenatal exposures and obstetric information on the birth of 5716 boys, collected from 1984 to 1987. During the 16-19 years of follow-up, 270 cases of cryptorchidism were diagnosed, and 185 of these boys underwent orchiopexy. RESULTS: Compared with nonsmokers, the adjusted risk ratio for being diagnosed with cryptorchidism was 1.1 (95% confidence interval = 0.8-1.6) if the mothers smoked 10-19 cigarettes/day and 2.3 (1.1-5.0) if they smoked > or = 20 cigarettes/day. The risk ratios for orchiopexy were 1.4 (0.9-2.1) and 1.8 (0.6-5.0), respectively. CONCLUSION: An excess risk of cryptorchidism was observed among sons of mothers who smoked 10 cigarettes or more per day during pregnancy. In recognition of the limited power of this study, the findings should be replicated in larger cohorts.