In the twentieth century, researchers developed the oral glucose tolerance test, or OGTT, as a method to diagnose different types of diabetes, a medical condition that causes blood sugar levels to become abnormally high. During the test, a healthcare provider measures a person’s blood sugar levels before and after the person consumes a predetermined amount of glucose solution. While not exclusively used for pregnant women, an OGTT may test for gestational diabetes which, according to the International Diabetes Federation, affected one in six pregnancies worldwide in 2019. Generally, the results from an OGTT can inform a patient and her physician how her body is responding to glucose during pregnancy, and high levels may increase her risk of developing adverse pregnancy outcomes such as heavy bleeding during delivery and a high blood pressure condition known as preeclampsia. An OGTT can help to accurately diagnose, treat, and monitor gestational diabetes in pregnant women, which can reduce health and pregnancy complications for the woman and the fetus.

Gestational diabetes is a medical condition that causes blood sugar levels to become abnormally high, which manifests for the first-time during pregnancy and typically disappears immediately after birth for around ninety percent of affected women. While many women with the condition do not experience any noticeable symptoms, some may experience increased thirst and urination. Although gestational diabetes is treatable, if left unmanaged, the resulting fetus is more likely to have elevated risks of increased birth weight, birth injuries, low blood sugar, stillbirth, and later development of type 2 diabetes. The International Diabetes Federation estimates that worldwide in 2019, gestational diabetes affected one in six pregnant women, with many cases occurring in women living in low and middle-income countries. Despite the prevalence and risks associated with gestational diabetes, as of 2020, researchers have yet to reach a unified consensus on the best guidelines for diagnosis and treatment.