Gestational Diabetes: The Reality

by Marion Toepke McLean, CNM

© 1993 Midwifery Today, Inc. All Rights Reserved.

[Editor's note: This column originally appeared in Midwifery Today, Issue 28, Winter 1993.]

When I was new to midwifery in the 1970s, testing for gestational diabetes was most commonly done after a stillbirth. And then the question was: Why didn't we learn this sooner?

At that time, a test for gestational diabetes nonintrusive enough for general screening in pregnancy did not exist. The test required dosing with 100 grams of glucose after a 12-hour fast, then drawing four blood samples, each an hour apart. Consequently, we reserved this test for women with risk factors. For the rest of our clients, we relied on testing the urine for glucose. However, this revealed only a small number of the total cases.

A few years ago, the American Diabetic Association approved a simple screening test. After a one-hour fast, 50 grams of glucose are ingested. One hour later, the blood glucose level is tested. A level greater than 140 milligrams suggests gestational diabetes. The test provided an opportunity to improve outcomes, especially since diet and exercise are adequate treatment in most cases.

Because of the simplicity of the test, I was surprised when many women resisted the screening. One woman told me she thought that gestational diabetes is an imaginary disease and brought me a magazine article to prove her point. But a friend of mine lost her baby to gestational diabetes in the late '70s, so to me the condition is very real.

She had a normal pregnancy, but was postdates. Her midwives talked about a nonstress test, but she went into labor before the test was done. They checked on her several times during a day of prodromal labor. The fetal heart rate was good, and fetal movements were noted. The following morning, her contractions came on strong. When the midwives returned to her house, she was 4 centimeters dilated—but no fetal heart tones were detected. The consulting obstetrician reported an abnormal three-hour glucose tolerance test. The diagnosis was gestational diabetes.

What had happened? The pancreas of the diabetic mother produced insufficient insulin. Consequently, glucose levels, which can damage many organs, rose in the mother's and baby's bloodstreams. The baby's young, strong pancreas increased its own insulin production, normalizing its blood sugar. Levels were stabilized, though at the cost of some fetal compromise. Then, during labor, the mother's food intake decreased and no more glucose diffused across into the baby's blood. The baby's own abnormally high insulin levels quickly metabolized the glucose within her body, her blood sugar plummeted, she went into shock and died.

Good glucose control in pregnancy prevents the overproduction of insulin by the baby's pancreas and subsequent episodes of hypoglycemia in late pregnancy or the neonatal period. My friend has two healthy children today, the result of carefully monitored pregnancies with dietary control of gestational diabetes.

But even with screening and monitoring, I had a close call a couple of years ago. The woman was on a diabetic diet and blood sugar testing. She always reported normal blood sugars. However, it did seem like she was gaining a lot of weight, and at term, her baby measured large.

In labor, she dilated normally, up to 9-plus centimeters. For the next three hours, the lip remained, tapering off to a thin rim. She stood; she squatted. The baby's baseline heart rate rose a little. I heard no more accelerations, nor any decelerations; the fetal monitor confirmed this. The fluid remained clear. When I checked her, the cervix was so stretchy I could push it back over the head, which was within reach but not engaged. She had no urge to push. Should I give it a try? I thought about the big baby, his uncertain status and the stresses that can occur during a vaginal delivery. I decided against asking her to try to push the baby on through. My obstetrician consultant was notified of the arrest of labor. Another period of observation ensued without complete dilatation. Finally, she underwent cesarean section.

The 11-pound boy was pulled out limp and pale. He was resuscitated, and an IV was started to correct his very low blood sugar. It was several days before he was stable without the IV. Why did we have a sick baby when the blood sugars were normal during pregnancy? The mother confided in the doctor who was caring for the baby. "She was bingeing," he told me. "She followed the diet and recorded her blood sugars one hour after each meal. They were basically normal. But she didn't report her bingeing, and she never checked her blood sugar after a binge." So, we had a sick baby who, with lots of high-tech care, survived to become a healthy boy.

What is the moral to the story? Gestational diabetes is a reality, and it can be a serious problem for both mother and baby; but detection and treatment, along with the mother's cooperation, can prevent problems for mother and baby. Midwives should monitor their mothers and initiate appropriate gestational diabetes care for those with the disease.

Marion Toepke McLean is a 1966 graduate of Pacific Lutheran University School of Nursing in Tacoma, Washington, and a 1974 graduate of Frontier Nursing Service School of Nurse Midwifery in Hyden, Kentucky. She practices in birth center and hospital settings in Eugene, Oregon, and lives with her family in the town of Dexter.

If you enjoyed this article, you'll enjoy Midwifery Today magazine! Subscribe now!