Interactive diabetes case 11: A 34-year-old pregnant patient with type 2 diabetes – D2

ANSWER — Correct.

These insulin doses were calculated using an algorithm with a total daily dose of 0.8 units/kg for weeks 13 to 28 of pregnancy. Two-thirds of the total daily dose is given before breakfast in a two-to-one ratio of NPH to a very short-acting insulin, such as lispro or aspart; one-sixth of the total daily dose is given as a very short-acting insulin before supper; and one-sixth of the total daily dose is given as NPH at bedtime. Adjustments are made every one to two weeks or as needed [1]. (See "Pregestational (preexisting) diabetes mellitus: Antenatal glycemic control".)

Very short-acting insulin analogs, such as lispro or aspart, are convenient to use during pregnancy because they can be given immediately before meals, in contrast with regular insulin, which must be given approximately 30 minutes before meals. They may produce better management of postprandial glucose levels and less hypoglycemia than regular insulin.

The patient returns in one week. The glucose meter memory indicates a progressive fall in glucose values over the first three days, and the following glucose values in the last four days: 73 to 111 mg/dL (4.1 to 6.2 mmol/L) before breakfast, 131 to 161 one hour after breakfast, 84 to 119 before lunch, 121 to 152 one hour after lunch, 87 to 114 before supper, 118 to 143 one hour after supper, and 86 to 106 at 2 to 3 AM.

You conclude that these values are above the target values you have chosen: 70 to 95 mg/dL (3.9 to 5.3 mmol/L) for fasting and preprandial values; 110 to 140 (6.1 to 7.8 mmol/L) for one-hour postprandial values. You are especially concerned about the postprandial values after breakfast and lunch. You review the patient's carbohydrate intake at those meals, finding it higher than recommended, and suggest appropriate adjustments in portion size. You increase the morning insulin dose to NPH 30 units and aspart 18 units. You advise the patient to take aspart insulin 5 units before lunch if the one-hour postprandial glucose values after lunch continue to exceed 140 mg/dL (7.8 mmol/L) after the changes in diet and morning doses of insulin. You advise the patient that it is no longer necessary to check glucose values at 2 to 3 AM and to return in one week. You see the patient every four weeks during her pregnancy, increasing the insulin doses as her requirements rise during pregnancy. The patient's glycated hemoglobin (A1C) is 6.4 percent at 16 weeks of pregnancy, 6.0 percent at 20 weeks, 5.8 percent at 24 weeks, 5.6 percent at 28 weeks.

The patient develops proliferative retinopathy and a vitreous hemorrhage in the left eye at 27 weeks of pregnancy. She receives multiple laser treatments to both eyes. The vitreous hemorrhage resolves. The patient is hospitalized at week 28 for eight days because a 24-hour urine collection contains 2614 mg of protein per 24 hours. A repeat collection in the hospital contains 4785 mg of protein per 24 hours. A nephrologist states that the differential diagnosis is between diabetic nephropathy and preeclampsia. The blood pressure is satisfactory during the admission. The patient is discharged with a diagnosis of diabetic nephropathy.

The patient is admitted at 36 weeks of gestation for induction of labor because of the presence of active retinopathy and nephropathy. The child is a healthy boy with an Apgar of 9 out of 9, weighing 2660 grams.

Six months after delivery, the patient's A1C is 6.7 percent and the urine micro albumin/creatinine ratio is 325 mg/g.

The management of this patient is discussed further elsewhere. (See "Interactive diabetes case 11: A 34-year-old pregnant patient with type 2 diabetes – Comment".)