The reproductive history of 100 women with at least 1 child with a neural tube defect (NTD) has been studied. The data analyzed correspond to the period previous to their first visit to a genetic counseling service. A total of 204 pregnancies resulted in 205 outcomes. Of the 100 sibships, 14 (14%) had more than 1 affected member. The pregnancy was shorter than 28 weeks in 56/205 (27%) of the total outcomes. Of 104 evaluable previous outcomes, 34 corresponded to short pregnancies, positioned before an affected (23/60, 38%), a healthy (2/18, 11%), or an undiagnosed product (9/26, 35%). Short pregnancies subsequent to affected outcomes were also increased. The inter-gestational interval varied according to diagnosis: it was longer in the affected group than in the healthy one (0.1 > p > 0.05) and the subsequent intervals were shorter for the affected group (p < 0.05). An increased number of abortions adjacent to affected offspring and a changing fertility pattern, depending on the product diagnosis, point to an environmental etiological component in this high- risk NTD group of mothers. Copyright (C) 2000 S. Karger AG, Basel
