Gestational diabetes after surviving the first six months of my pregnancy with very few complaints, I thought I was home free, at least until delivery. I felt fine, and the routine urinalysis performed at each OB appointment had never detected sugar in my urine. Imagine my surprise, then, when I learned that I had flunked the one-hour glucose tolerance test routinely used around 24 to 28 weeks to screen for gestational diabetes (GD).
What Is Gestational Diabetes?
GD is a temporary type of diabetes that develops in 1 to 2 percent of all pregnancies. During pregnancy, the body triggers an “anti-insulin” mechanism via hormones secreted from the placenta to ensure that enough sugar remains in the mother’s bloodstream to nourish the fetus. But it is clearly an imperfect science: Sometimes too much sugar remains. The normal response is for the body to manufacture more insulin, but in GD patients the body is either unable to produce enough insulin at once, or the insulin that exists is not used efficiently.
The condition generally worsens as pregnancy progresses and the placenta continues to grow. Severe cases often require treatment with insulin, but milder ones can be diet-controlled.
In most GD cases, blood sugar levels return to normal as soon as the placenta is delivered.
Left untreated, GD is dangerous for both Mother and Baby. Without a proper breakdown of sugars, they pass undiluted through the placenta to the baby, creating large fat stores. The excessively large “macrosomic” babies can reach 12 or 13 pounds, undeliverable vaginally. Like non-pregnant diabetics, untreated mothers can suffer from kidney difficulties and vision problems. In addition, their placentas tend to deteriorate very rapidly, often prompting induced labors or Cesareans.
Happily, though, the diabetes is usually temporary. In most cases, blood sugar levels return to normal as soon as the placenta is delivered.
Glucose Tolerance
Because GD is so common, most obstetricians have made the one-hour glucose tolerance test on a standard screen. The test begins with a fasting blood sugar reading. The patient then drinks a cup of sugary syrup, waits an hour, and another blood sample is drawn.