Risk of minor and major fetal malformations in diabetics

Maternal haemoglobin Al, (HbA,,) values were measured before the end of the 15th week of gestation in 142 pregnancies in women with insulin dependent diabetes. In pregnancies complicated by fetal malformations (n=: 17) the mean initial HbAl, value was 9 5 (SD 1 8)% of the total haemoglobin concentration, which was significantly (p <0 001) higher than in pregnancies without malformations (8 0 (SD 1 4)%; n=125). HbA1, values did not differ between pregnancies complicated by minor and major fetal malformations, but the rate of malformations showed a positive relation to the HbAl, value in early pregnancy (x2=119; p=0 001). Fetal malformations occurred in six out of 17 pregnancies (35-3%) in mothers whose initial HbA1, value was 10% or more, in eight out of 62 pregnancies (12 9%) in mothers with initial values between 8 0% and 9 9%, and in only three out of 63 pregnancies (4 8%) in mothers with an initial value below 8 0%. These data support the hypothesis that the increased incidence of fetal malformations in mothers with insulin dependent diabetes is associated with maternal hyperglycaemia during organogenesis. Hence diabetic women who are planning to have a child-especially those with a high HbAlc value-should receive intensified metabolic control.