A population-based case-control study of the safety of oral anti-tuberculosis drug treatment during pregnancy

OBJECTIVE: TO study the human teratogenic potential of isoniazid and other anti-tuberculosis drug treatment during pregnancy. DESIGN AND SETTING: Cases from a large population-based dataset at the Hung arian Case-Control Surveillance of Congenital Abnormalities, and controls f rom the National Birth Registry, between 1980 and 1996. Information on all oral anti-tuberculosis drug treatments during pregnancy was medically recor ded. STUDY PARTICIPANTS: Women who had newborns or fetuses with congenital abnor malities (case group), and women who had babies with no congenital abnormal ity (control group). MAIN OUTCOME MEASURES: Congenital abnormalities in newborn infants and fetu ses diagnosed prenatally during the second and third trimesters, and postna tally from birth to the age of one year. RESULTS: Of 38 151 controls, 29 (0.08%) were exposed to anti-tuberculosis d rug treatment during pregnancy; the corresponding figures for cases were 22 865 and 11 (0.05%). The prevalence odds ratio was 0.6 (95% CI 0.3-1.3). An alysis of isoniazid and other oral antituberculosis drug use during the sec ond and third months of gestation, i.e., in the critical period for most ma jor congenital abnormalities, in case-control pairs did not indicate a tera togenic effect of these drugs in any group with congenital abnormality. CONCLUSION: Maternal exposure to oral anti-tuberculosis drugs during pregna ncy did not show a detectable teratogenic risk to the fetus; however, the n umber of pregnant women who were treated with these drugs during the critic al period of most major congenital abnormalities was limited (six cases vs. 21 controls).