Peri-Conceptional A1C and Risk of Serious Adverse Pregnancy Outcome in 933 Women With Type 1 Diabetes

OBJECTIVE

To study the association between peri-conceptional A1C and serious adverse pregnancy outcome (congenital malformations and perinatal mortality).

RESEARCH DESIGN AND METHODS

Prospective data were collected in 933 singleton pregnancies complicated by type 1 diabetes.

RESULTS

The risk of serious adverse outcome at different A1C levels was compared with the background population. The risk was significantly higher when peri-conceptional A1C exceeded 6.9%, and the risk tended to increase gradually with increasing A1C. Women with A1C exceeding 10.4% had a very high risk of 16%. Congenital malformation rate increased significantly at A1C above 10.4%, whereas perinatal mortality was increased even at A1C below 6.9%.

CONCLUSIONS

These results support recent guidelines of preconceptional A1C levels <7% in women with type 1 diabetes.Recently, guidelines for management of pregnancy in women with pregestational diabetes have recommended pregestational A1C values <7.0% (1,2) and <6.1% (3). Previous studies have reported information of early A1C including 116–691 pregnancies (4–10). We aimed to study whether there is a threshold value for peri-conceptional A1C in women with type 1 diabetes below which the risk of serious adverse pregnancy outcome (congenital malformation and perinatal mortality) is not increased.