Pregnant women who develop marked increased blood sugar levels during pregnancy can reduce the risk of certain birth complications if they receive treatment. This is a prerequisite for offering all pregnant women routine screening for gestational diabetes. However, potential disadvantages of this type of routine screening have not been thoroughly researched ...
Even today, most pregnant women in Germany are unsystematically offered a blood sugar test to identify those women whose blood sugar levels rise too much during pregnancy ...
... "We cannot be certain that the tests as currently carried out in the doctor's surgery yield more benefit than harm."
Gestational diabetes is a question of definition
During pregnancy it is normal that a woman's metabolic rate changes and sugar takes longer to be absorbed by the body. In May 2008 an international study confirmed that rising blood sugar levels increase the risk, for example, of a Caesarean section or birth injuries. However, there is disagreement over when increased blood sugar levels should be treated, as there is no threshold where these risks increase dramatically.
Nevertheless, it should be noted that a diagnosis of gestational diabetes has far-reaching consequences for a pregnant woman. Not only does she have to accept the unpleasant news that something is not right, she also has to adapt her diet and take more physical exercise. In addition, blood sugar levels have to be measured several times a day and, if they do not drop to the prescribed targets within a short time, daily insulin injections have to be administered.
Treatment can have positive effects
... treatment reduces the risk of certain rare birth complications in pregnant women with a marked metabolic disorder. One such complication is shoulder dystocia ...
Potential disadvantages of routine screening have not been researched
Even if there is an indication of benefit from treatment, this does not automatically mean that routine screening is also useful for identifying pregnant women with gestational diabetes. Although some professional associations have been recommending this type of screening for many years, potential harms have not yet been sufficiently investigated. IQWiG could not find any studies which directly showed that routine screening was of more benefit than harm.
In view of this uncertainty, the Institute considered a long list of potential disadvantages. However, the potential risks were not assessed as being so serious that they might cancel out the potential benefit. Thus, the Institute has indirectly deduced an indication that routine screening for gestational diabetes leads to a reduction in perinatal complications.
... Experts around the world are not agreed on how women with a metabolic disorder should be routinely identified.
... Consequently, many tests for gestational diabetes that are already being offered to pregnant women should be viewed critically. "These tests label many pregnant women as being at risk, without it being clear whether they would actually profit from having treatment", explains Sawicki. A harm is particularly likely if a woman with a mild metabolic disorder during pregnancy is recommended to have treatment which is too strong.
In IQWiG's opinion, therefore, a study that directly compares the advantages and disadvantages of different screening strategies for mother and child is overdue. According to Sawicki, "In view of the number of pregnancies per year in Germany (more than 600,000), such a study could be carried out relatively quickly." ...