Severe hypoglycemia during pregnancy: its frequency and predisposing factors in diabetic women.

Severe hypoglycemic episodes, as defined as altered consciousness to the extent that self treatment is impossible, were sought prospectively in pregnant diabetic women. One or more episodes were found in none of 21 gestational onset, insulin-requiring women during their 28 pregnancies but were present in 19 (33%) of the 57 already insulin dependent (Type 1) women during 26 (36%) of their 72 pregnancies. The most common predisposing factors included strict glucose control, anorexia, early morning hours (1200-0900), lack of an adrenergic response and time shortly before the next anticipated meal.