Gestational Diabetes Mellitus (GDM) is defined as diabetes that arises during pregnancy, and especially after the 24th week. Its prevalence in Western countries is estimated at 3-10% of pregnant women, given that different criteria for diagnosing gestational diabetes make it difficult to assess correctly. Because of its implications for the future health of the mother, newborn and pregnancy, GDM is a target for screening and early detection. In many countries, a glucose tolerance test is preformed between the 24th and 28th week of pregnancy. The test, despite its sweet name, is often experienced as tedious and unpleasant, given the time it consumes, and the challenge in drinking 50 or 100 grams of sugar in one gulp. In fact, many women were likely to give up the experience if they found a more convenient alternative. So is there such a possibility in sight?
An American study published two months ago examined the association between glycated hemoglobin (HbA1C) levels in the first trimester of pregnancy, and the later development of gestational diabetes. The results appear promising. The simple blood test was performed in all women at 8-13 gestational week, and in three later time points during pregnancy. The results? Glycated hemoglobin level was significantly higher in women who later developed diabetes, compared to controls. In addition, a woman’s chance of developing diabetes increased as A1C levels was higher, even when it was within normal range. The addition of this test to the conventional risk factors improved the ability to predict who will eventually develop gestational diabetes.
This study’s included women at low risk for gestational diabetes, and those without pre-existing medical conditions. This quality makes it relevant to the general population and differs it from past studies that only examined specific high-risk groups. The representation of a variety of ethnic groups also contributes to its over-all relevance.
Despite the promising findings, the researchers maintain restraint. Glycated hemoglobin test is not widely used today during pregnancy, and mainly reserved to confirm diabetes diagnosis, and to monitor glycemic control. It is not at all certain that the test is suitable to be used as screening for GDM. In addition, the HbA1C test has its limitations, that may impair accuracy. Such are the presence of anemia, or increased turnover of red blood cells, both are particularly common in pregnancy. These limitations are possible to control in a research framework, but not always in daily practice. In conclusion, further research is needed before (and if) the test will be recommended as a routine test in pregnancy, but these findings are definitely something to think about.