Congenital anomalies in the offspring of women with type 1, type 2 and gestational diabetes.
OBJECTIVE
To determine the frequency of major congenital anomalies in the offspring of women with gestational diabetes (GDM), classified according to their postpartum glucose tolerance status.


METHODS
A prospective study of pregnancies in women with Type 1 diabetes (n = 221), Type 2 diabetes (n = 317) and GDM (n = 1822) between 1985 and 2000 (15 years). Congenital anomalies were detected by antenatal ultrasound or postnatal examination.


RESULTS
The frequency of major congenital anomalies in the offspring was 5.9% (95% confidence interval (CI) 3.2-9.8) for women with Type 1 diabetes; 4.4% (95% CI 2.4-7.3) for women with Type 2 diabetes; and 1.4% (95% CI 0.9-2.0) for women with GDM. Two hundred and thirty-seven women with GDM (13%) had diabetes diagnosed on early (6-week) postpartum glucose tolerance testing. The frequency of major congenital anomalies in their offspring was 4.6% (95% CI 2.3-8.2), compared with 0.9% (95% CI 0.5-1.5) for the remainder of the GDM group (P < 0.0001).


CONCLUSIONS
GDM is not a homogeneous group with regard to the risk of major congenital anomalies. In those with diabetes on early postpartum testing, who are likely to have had unrecognized Type 2 diabetes antedating their pregnancy, the rate of major congenital anomalies is the same as for women with established Type 1 or Type 2 diabetes. In the remainder of the GDM group, the rate does not differ from the non-diabetic background rate.
Farrell
T
T
Department of Medicine, Faculty of Medicine & Health Sciences, University of Auckland, New Zealand.
Neale
L
L
Cundy
T
T
D001786:Blood Glucose / Q000378:metabolism; D000013:Congenital Abnormalities / Q000453:epidemiology*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood; D003924:Diabetes Mellitus, Type 2 / Q000097:blood; D016640:Diabetes, Gestational / Q000097:blood; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy; D012189:Retrospective Studies
D001786:Blood Glucose