SMOKING DURING PREGNANCY AND CONGENITAL LIMB DEFICIENCY

Objective-To examine genetic and environmental factors in the origin of isolated congenital limb deficiencies. Design-Case-control study with questionnaire at a family interview of cases of isolated congenital Limb deficiencies (six types), negative controls (matched for age, sex, and place of residence), and positive controls (cases of sentinel anomalies). Setting-The database of the Hungarian Congenital Abnormality Registry, 1975-84, complemented by three other sources of ascertainment (1 575 904 births). Subjects-537 case-control pairs; 392 positive controls. Main outcome measures-smoking during pregnancy, congenital limb deficiencies. Results-The adjusted rate of smoking during pregnancy was significantly higher in the mothers of cases of terminal transverse defect (relative odds 1.48; 95% confidence interval 0.98 to 2.23; P=0.017). This finding supports the hypothesis of vascular disruption as a cause of congenital limb deficiency. Conclusions-Maternal smoking during pregnancy raises the relative odds for terminal transverse limb deficiencies.