Tests for postpartum screening of women with hyperglycaemia in pregnancy (including gestational diabetes)

The tests used for postpartum screening of women with hyperglycaemia in pregnancy (including gestational diabetes) should be individualised and organised postpartum—see Screening women who had diabetes mellitus in pregnancy and Screening women who had gestational diabetes for details on which tests are appropriate and the timing of the tests. For general information on diagnostic tests for diabetes, see Tests to diagnose diabetes.

Early detection of abnormal glucose tolerance is particularly important in women with hyperglycaemia in pregnancy (including gestational diabetes) because there is the potential to prevent or delay the onset of diabetes and reduce the risk of adverse outcomes in future pregnancy. In women who have had hyperglycaemia in pregnancy (including gestational diabetes), most will develop impaired glucose tolerance (elevated blood glucose concentration 2 hours after an oral glucose tolerance test) before they have an elevated fasting blood glucose concentration. An oral glucose tolerance test is the only test that can detect impaired glucose tolerance.

An HbA1c test may be used for ongoing screening of women who had hyperglycaemia in pregnancy; for details on interpretation of results in these patients, see Screening women who had diabetes mellitus in pregnancy and Screening women who had gestational diabetes. Do not use HbA1c for diagnosis of diabetes or monitoring blood glucose concentrations within the first 3 months after delivery. HbA1c will be falsely low because of the lower blood glucose concentrations during pregnancy (due to haemodilution of pregnancy), the increased red blood cell turnover and/or shorter red cell lifespan in pregnancy, and peripartum blood loss (for limitations of HbA1c testing, see Limitations of HbA1c tests).