Malformations among infants of mothers with insulin-dependent diabetes: Is there a recognizable pattern of abnormalities?

BACKGROUND

Infants of diabetic mothers have been shown in several studies to have an increased frequency of malformations. In previous studies, an increased frequency of several specific malformations has been noted, including anencephaly, bilateral renal agenesis, and double outlet right ventricle. Surveillance, used to identify all malformed infants in a consecutive sample of births, can identify a distinctive pattern of malformations among the affected infants.

METHODS

The infants of insulin-dependent, pregestational diabetic mothers were identified in the daily review of the medical records of each newborn infant with a malformation and her/his mother's medical record. Infants of mothers with gestational diabetes were excluded. The frequency of each malformation was compared to that among the malformed infants of nondiabetic mothers.

RESULTS

One hundred and eighty-three malformed infants of diabetic mothers were identified among the 289,365 births. The most notable malformations were: neural tube defects (anencephaly, 9%), heart defects (transposition of great arteries, 4%), bilateral renal agenesis or dysgenesis (6%), and vertebral anomalies (hemivertebrae, 4%).

CONCLUSIONS

There was a recognizable pattern of malformations and characteristics of infants of diabetic mothers, although there was variation in the pattern among affected infants. Some of the malformations in the diabetic embryopathy can be identified in prenatal screening by ultrasound. More important, their occurrence can be reduced significantly by the mother achieving much better control of her diabetes mellitus prior to conception.