What is this Condition?

Pregnancy places special demands on carbohydrate metabolism and increases the body’s insulin requirement, even in a healthy mother. Thus, she may become prediabetic, or, if she’s diabetic, runs the risk of aggravating her preexisting condition.

The prognosis of the mother and fetus is good if the mother’s blood glucose (sugar) level is well controlled and ketosis and other complications are prevented. Infant morbidity and mortality depend on recognizing and successfully controlling low blood sugar, which may develop within hours after delivery.

What Causes it?

In diabetes, glucose is inadequately used by the body, either because insulin is not synthesized by the pancreas (as in insulin-dependent diabetes) or because body tissues resist the hormonal action of endogenous insulin (as in non-insulin-dependent diabetes). During pregnancy, the fetus relies on the mother’s glucose as a primary fuel source, but pregnancy triggers protective mechanisms that have anti-insulin effects: increased hormone production (placental lactogen, estrogen, and progesterone), which counteracts the effects of insulin; degradation of insulin by the placenta; and prolonged elevation of stress hormones (cortisol, epinephrine, and glucagon), which raises blood sugar levels.

In a normal pregnancy, an increase in anti-insulin factors is met by increased insulin production to maintain normal blood sugar levels. However, prediabetic or diabetic women can’t produce enough insulin to overcome the insulin antagonist mechanisms of pregnancy, or their tissues are insulin-resistant. As insulin requirements rise toward term, a prediabetic woman may develop gestational diabetes, requiring dietary management and, possibly, administration of insulin to achieve glucose control; an insulin-dependent woman may need to increase her insulin dosage.

What are the Symptoms?

Indications for diagnostic screening for maternal diabetes during pregnancy include obesity, excessive weight gain, excessive hunger or thirst, excessive urination, recurrent monilial infections, glucose in the urine, previous delivery of a large infant, excessive amniotic fluid, maternal high blood pressure, and a family history of diabetes.

Uncontrolled diabetes in a pregnant woman can cause stillbirth, fetal anomalies, premature delivery, and birth of an infant who is large or small for gestational age. Such infants are predisposed to severe episodes of low blood sugar shortly after birth and may also develop calcium deficiency, high levels of bilirubin in the blood, and respiratory distress syndrome.

How is it Diagnosed?

The prevalence of gestational diabetes makes careful screening for high blood sugar appropriate in all pregnancies in each trimester. Abnormal blood sugar levels measured in a fasting person or after she has eaten, signs and symptoms, and the person’s history suggest diabetes in women not previously diabetic.

A 3-hour glucose tolerance test confirms diabetes when two or more values are above normal.

Procedures to assess fetal status include stress and nonstress tests, ultrasound to determine fetal age and growth, and measurement of urine hormone levels.

How is it Treated?

Treatment of both newly diagnosed and established diabetes is designed to maintain the woman’s blood sugar levels within acceptable limits through dietary management and insulin administration. Most pregnant women with overt diabetes require hospitalization at the beginning of pregnancy to assess physical status, to check for heart and kidney disease, and to regulate diabetes.

Generally, the optimal time for delivery is between 37 and 39 weeks’ gestation. An insulin-dependent diabetic woman requires hospitalization before delivery because bed rest promotes optimal circulation to the fetus and improves uterine muscle tone. In addition, hospitalization permits frequent monitoring of blood sugar levels and prompt intervention if complications develop.

Depending on fetal status and maternal history, the obstetrician may induce labor or perform a cesarean delivery. During labor and delivery, the woman with diabetes will receive a continuous intravenous infusion of dextrose with regular insulin in water. Maternal and fetal status must be monitored closely throughout labor. The woman may benefit from half her prepregnancy dosage of insulin before a cesarean delivery. Her insulin requirement will fall markedly after delivery.