Pregnancy in a Diabetic Patient. Prenatal Care — The First Trimester

Maternal Complications, Management, and Monitoring

The main goal in caring for a pregnant diabetic patient in the first trimester is maintenance of near-perfect glycemic control, which should have been achieved prior to conception. Weekly (or at least every two weeks) physician visits are necessary in the earlier part of the pregnancy. Patients should perform home blood glucose monitoring at least four times a day, with three before meals and one before bedtime. Hemoglobin A1c levels should also be checked every 4­-6 weeks during this period. Insulin requirements should be individualized and insulin given accordingly. There is no clear standard on how many daily injections should be given or what the ratio should be between the regular and intermediate-acting insulin. Each patient’s dose will be individualized based on the results of the blood glucose monitoring and HbA1c levels.

In a study by Schuster et al., 93 women were followed during pregnancy to assess the efficacy of using premixed insulin (70% NPH/30% Regular) by injectable pen versus the traditional self-mixed insulin administered by syringe. The women were enrolled into four different groups: 1) self-mixed/ syringe, 2) premixed/syringe, 3) self-mixed/pen, and 4) premixed/ pen. The study found a significant difference (p = 0.03) of fewer cesarean deliveries for failure to progress to labor in the women in the premixed pen group. However, no significant differences were noted in glucose control, compliance, cost, incidence of infections, or infant macrosomia. Therefore, tight glycemic control by close monitoring and individualized dosing, using a variety of dosing and administration techniques, will result in a positive outcome.

Since insulin requirements fluctuate in early pregnancy, the patient, family, and physician must watch for signs and symptoms of hypoglycemia, which may occur without warning. Patients should be warned about the dangers of missing meals and instructed in the use of glucagon. The patient must also be instructed on how to change the insulin dosage as needed based on the results of the blood glucose test results. For the patient on a twice-daily regimen, the morning short-acting regular insulin should be adjusted on the before-lunch test result and the morning intermediate-acting NPH insulin dose on the before-dinner meal test. Evening short-acting regular insulin should be adjusted on the bedtime test and the evening intermediate-acting insulin on the before-breakfast test. Keep in mind that the adjustment is always 24 hours behind.

Achieving good glycemic control is further complicated in early pregnancy by nausea and vomiting (morning sickness). Good glycemic control is of particular importance, since morning sickness increases the risk of ketoacidosis and fetal loss. Patients are advised to manage nausea initially by changing dietary habits, such as eating dry crackers or toast before rising, eating frequent small meals and snacks, drinking liquids between meals rather than with meals, and avoiding caffeine and foods that are spicy or have a high fat content. If the nausea is severe, antinausea medications should be utilized. Table 5 lists the antiemetics that have been used in managing hyperemesis gravidarum. Vomiting that is severe may require patients to be hospitalized for intravenous nutrition, especially if ketonuria is present, or to be put on home IV therapy.

Diabetic ketoacidosis (DKA) is another complication that can occur in early and late pregnancy. DKA is associated with a fetal mortality of about 35%. It is a condition characterized by insulin deficiency, hyperglycemia, and acidosis. This is considered a true medical emergency, for both the mother and the fetus. The presenting signs and symptoms of DKA are vomiting, polydipsia, polyuria, weakness, abdominal pain, weight loss, hyperventilation, dry mucous membranes, tachycardia, hypotension, disorientation, and coma. Factors that predispose a pregnant diabetic woman to ketoacidosis are listed in Table 6. Pregnant diabetic patients can develop DKA at a lower glucose level than that seen in a nonpregnant diabetic patient. For the manifestations of diabetic ketoacidosis to develop, the glucose level is at least 300 to 350 mg/dL in a nonpregnant diabetic patient, while in the pregnant diabetic patient, the signs and symptoms leading to diabetic ketoacidosis have been observed with glucose levels as low as 200 mg/dL.

Pregnant patients with diabetic ketoacidosis should be admitted to an intensive care unit and appropriate management initiated. Management goals of a pregnant DKA patient are maternal stabilization, hydration, and reversal of hyperglycemia and metabolic acidosis. Attainment of these goals will also result in decreased fetal hypoxemia, acidosis, and hypokalemia. If the pH is less than 7.0, management consists of fluid replacement, insulin administration, potassium replacement, and bicarbonate replacement. Table 7 lists some specific measures to acutely manage diabetic ketoacidosis in pregnancy.

Fetal Complications

In the first trimester the main complication for the fetus is the development of congenital mal-formations due the hyperglycemic states of the mother. All abnormalities occur during the first eight weeks of pregnancy; therefore, glucose control must start prior to pregnancy. In a study by Fuhrmann et al., the authors followed 292 diabetic women who began strict metabolic control after 8 weeks gestation and 128 diabetic women who began intensive treatment before conception. In the first group there were 22 infants with congenital malformations versus one malformation in the second group (p <0.01). The same authors also reported studying 56 women who were normoglycemic in the early weeks of gestation versus 144 pregnant diabetic patients who were only seen after eight weeks of pregnancy, with no preconceptional metabolic control. They report one infant with a fatal heart malformation in the normoglycemic women versus nine congenital malformations (three fatal, three severe, and three minor) in the women who were not normoglycemic in the initial weeks of pregnancy. These studies clearly indicate the need for achieving and maintaining glucose control in the initial stages of pregnancy to decrease the incidence of congenital malformations.