Down's syndrome and maternal cancer. A preliminary study.

The possible association between maternal cancer and Down's syndrome was studied in a register-based case-control study of 962 women who had an infant with Down's syndrome born during 1973-1981, and to each two controls, matched for maternal age, parity, and year of delivery. A total of 952 complete triplets was obtained. Among them, 63 Down's syndrome mothers and 79 control mothers were found in a cancer registry for the period 1958-1982 (odds ratio 1.6;95% conf. interval 1.3-2.0). Of these, 14 Down's syndrome mothers and 20 controls had malignant lesions (odds ratio 1.4, 0.9-2.2), and 49 Down's syndrome mothers and 55 controls had cervical cancer in situ (odds ratio 1.8, 1.4-2.3). This risk increase was present both before and after the delivery of the Down's syndrome infant. Various explanations of these findings are discussed and the need for further data is stressed.