Congenital Malformations in Newborns from Diabetic Mothers

Abstract

It has been well known that there is a high incidence of congenital malformations in newborns from diabetic mothers when the mothers' diabetes control before and during pregnancy is poor. We treated 438 pregnant diabetics who bore 443 children between February 1964 and June 1992. Among these children, there were 51 cases (11.5%) with congenital malformations, 21 cases with major anomalies (4.7%) and 30 cases with minor anomalies (6.8%). The type of malformations are not related to special organs; heart malformations and cleft lips are relatively frequent compared to other types of malformations. The mechanism of the congenital malformations in newborns from diabetic mothers remains unclear. However, clinically and experimentally it has been found to be due to fuel-mediated teratogenesis. Since October 1978, HbAi has been used as an index of diabetic control and the relationship between congenital malformations and the mother's diabetes control has been observed. 1) There is no difference in the incidence of malformations in children from IDDM and NIDDM mothers. However, there are more severe malformations in the children from IDDM mothers compared to those from NIDDM mothers. 2) Mothers who bore children with major malformations had all made their first visit to our hospital after pregnancy. HbAi in the IDDM mothers who had children with malformations at the first visit was 11%. 3) In the NIDDM mothers, even if HbAi levels are near normal, children with major malformations were born and there was little relationship between congenital malformations and the mothers' diabetes control. These data suggest that there are two kinds of congenital malformations in children from diabetic mothers, fuel-mediated teratogenesis, and malformations as seen in children from non-diabetic mothers.