A prospective study of some aetiological factors in limb reduction defects in Sweden.

Two groups of infants with limb reduction defects were studied: all such infants born in Sweden 1983-1986, and infants with severe reduction deformities born in 1973-1981. Data on the use of oral contraceptives, intrauterine devices, and drugs, and on maternal smoking were retrieved from information collected in early pregnancy as a part of routine maternity health service records. It was not possible to substantiate the association, described repeatedly in the literature, between limb reduction defects and the use of oral contraceptives just before or in early pregnancy. Various explanations for this discrepancy are discussed. An association with maternal diabetes was seen but not with drugs used for thyroid disease. A weak and statistically non-significant association with maternal smoking was found for severe limb reduction defects.