Use of medication during pregnancy and risk of childhood leukemia (Canada)

To examine risk of childhood acute lymphoblastic leukemia (ALL) associated with maternal use of medications during pregnancy; in particular medications known or suspected to be teratogenic.

Seven hundred and eighty nine children (< 15 years old) diagnosed with ALL in the province of Quebec between 1980 and 2000 were recruited for study. A similar number of population based controls matched to cases (1:1) by sex and age were chosen from family allowance or health insurance files. Information was gathered via telephone interview with the subjects' parents. Data were analyzed using conditional logistic regression.

Risk of childhood ALL was significantly increased in the offspring of mothers who reported using any medication (adjusted odds ratio (OR(adj)) = 1.3, 95% CI = 1.0-1.6) or any teratogenic medication (OR(adj) = 1.4, 95% CI = 1.1-1.9) during pregnancy. Among specific medication categories, only central nervous system depressants were associated with a significantly increased risk, although elevated odd ratios were found for anti-epileptics, immunosuppressants, oral contraceptives, and illicit drugs. Risk associated with use of teratogenic medications was higher with increased dose and in children diagnosed before two years of age.

A modest increase in risk of ALL was found among children of mothers who used medication during pregnancy.