Diabetes and Pregnancy
There are different types of diabetes that affect pregnancy. Type I and Type II diabetes are both diagnosed prior to pregnancy. Gestational diabetes is acquired during pregnancy by women who have not had a history of high blood glucose levels. All types of diabetes are important causes of maternal and fetal morbidity and mortality. Diabetic patients are considered “high risk” pregnancies, and they are monitored closely by physicians, dieticians, nurses and ultrasound exams. Patients may be managed by a perinatologist, which is a doctor trained in obstetrics and gynecology, who is further trained to take care of high-risk pregnancies.
Women who do not have their diabetes controlled at the time of conception have a higher risk of developing a baby with a birth defect. Birth defects can occur in the brain, spine, and heart. Diabetes can also lead to miscarriage. Defects and complications occur because the increased glucose levels affect the early development of the baby’s organs. Since gestational diabetes occurs later in the pregnancy, the glucose does not affect the developing organs in the same way. The gestational diabetic has less risk of congenital defects than the patient with Type- 1 or Type 2 diabetes.
A routine glucose tolerance test (GTT) is done between 24 and 28 weeks of gestation to determine if the patient is at risk for developing gestational diabetes. An initial blood glucose test is taken to determine the fasting level. A one-hour glucose test requires the pregnant woman to drink a 50 gram glucose solution which usually comes in different flavors. She gets her blood drawn prior to drinking the solution and one hour after to check her glucose levels. This test shows how her body reacts to the sugar solution. The results are considered abnormal if the fasting blood sugar level is over 95 mg/dl or exceeds 140 mg/dl one hour after drinking the solution. If the results are abnormal, the patient is then sent for a three-hour test. This test requires the patient to drink a 100 gram glucose solution and the blood is drawn every hour for three hours. If two values are above a certain level, gestational diabetes is diagnosed.
A diabetic pregnant patient must monitor and control glucose levels very carefully. She must test glucose levels several times a day. The patient may control her glucose with either diet or with insulin. Untreated or poorly controlled gestational diabetes can hurt the developing baby. Glucose crosses through the placenta, giving the baby high blood glucose levels. This causes the baby's pancreas to make extra insulin to get rid of the blood glucose. The baby gets more energy than it needs to grow and develop and stores it as fat. This can lead to macrosomia, or a "fat" baby, which can also lead to problems with the delivery. If the baby weighs more than 4,000 grams, the patient’s clinician will be alerted to problems of dystocia with vaginal delivery and may prefer a cesarean section. Dystocia occurs when the head is delivered but the baby gets caught in the birth canal at the level of the shoulders. This is an emergency situation that can lead to nerve damage in the baby and may even lead to the baby’s demise.
The diabetic pregnancy may also develop polyhydramnios, which is an increased level of fluid in the amniotic sac. Polyhydramnios can be a sign of another malformation and can also lead to preterm labor. A preterm baby may have respiratory distress syndrome and require being placed in the high risk nursery.
Diabetes significantly affects the clinical management of the patient due to all the complications that can be encountered. The clinical judgment of an obstetrician experienced in diabetic pregnancy is essential. Ultrasound scanning must be available for assessing gestational age, examining for congenital abnormalities and monitoring fetal growth. These patients need early ultrasound exams and also are monitored with ultrasound to evaluate fetal well being. Monitoring the pregnancy with ultrasound may occur once and perhaps even two times per week. The patient may also have weekly consultations with dieticians or nurses to follow-up on glucose levels. The patient may require changes in diet and/or changes in levels of insulin that is administered.
Obstetrical patients that acquire gestational diabetes have a 50% risk of becoming diabetic within five years if they require insulin during the pregnancy. If the diabetes was controlled through diet, there is a 60% risk of developing diabetes within 10-15 years. Evidence shows that lifestyle alteration may delay or prevent the onset of diabetes. Gestational diabetic patients should have a glucose tolerance test approximately six weeks after delivery to evaluate their blood glucose levels.