A population-based study of survival and childbearing among female subjects with birth defects and the risk of recurrence in their children

Background and Methods Persons with birth defects are at high risk for death during the perinatal period and infancy. Less is known about the rater survival or reproduction of such persons. We studied a cohort that comprised 8192 women and adolescent girls with registered birth defects and 451,241 women and adolescent girls with no birth defects, all of whom were born in Norway from 1967 through 1982. The rate of survival was determined through 1992, and the rate of childbearing was determined through October 1997. We also estimated the risk of birth defects in the children of these subjects. Results Among the subjects with birth defects, 80 percent survived to 15 years of age, as compared with 98 percent of those with no birth defects. Among the surviving subjects, 53 percent of those with birth defects gave birth to at least one infant by the age of 30 years, as compared with 67 percent of those with no birth defects. The subjects with birth defects were one third less likely to give birth by the age of 30 than those with no birth defects. The children of the subjects with birth defects had a significantly higher risk of birth defects than the children of those with no birth defects (relative risk, 1.6; 95 percent confidence interval, 1.3 to 2.1). This increased risk was confined entirely to the specific defect carried by the mother, with the relative risk of recurrence varying from 5.5 to 82 according to the defect. In contrast, there was no increase in the risk of having an infant with a different type of defect. Conclusions Women and girls with birth defects have decreased survival as compared with those with no birth defects, especially in the first years of life, and are less likely to have children. in addition, they have an increased risk of having children with the same defect. (N Engl J Med 1999;340:1057-62.) (C) 1999, Massachusetts Medical Society.