The correct answer is:

Hyperemesis is one of the most common precipitants.

Educational Objective:

Discuss common etiologies of coma during pregnancy due to diabetic ketoacidosis.

Key Points:

Hyperemesis and noncompliance or errors in insulin dosage are the most common precipitants of diabetic ketoacidosis in the pregnant patient. Admission is often indicated to correct dehydration and more carefully adjust glucose control.

Explanation:

The serum pH may be deceptively normal in the pregnant patient, because the initial pH tends to be higher in pregnancy due to physiologic hyperventilation. DKA is rare in patients with gestational diabetes, and serum glucose may be only moderately elevated because the fetus continues to secrete insulin and use glucose. 

The rate of congenital malformations in patients with diabetes is increased threefold or fourfold compared with the nondiabetic population, with anomalies being more likely in pregnant women with poor glycemic control. Preeclampsia and placental infarction secondary to vascular disease may result in impaired fetal development and stillbirth 

Maternal mortality is rare in appropriately treated DKA. Fetal mortality rates are relatively high, ranging from 10 to 35%.

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