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.
In April 1994, Elizabeth Raymond, Sven Cnattingius, and John Kiely published “Effects of Maternal Age, Parity, and Smoking on the Risk of Stillbirth” in the British Journal of Obstetrics and Gynecology, now known as BJOG: An International Journal of Obstetrics and Gynecology. The article examines how advanced maternal age, defined as delivery at thirty-five years old or older, cigarette smoking, and nulliparity, or the state of never having given birth, can negatively impact pregnancy. At the time of publication, according to Raymond and colleagues, stillbirths comprised over half of all perinatal, or close to birth, deaths and more than one-third of total fetal and infant deaths in Europe and North America. In the article, Raymond and her coauthors demonstrate how certain risk factors may increase the risk of stillbirth at different stages of pregnancy, which helped set a foundation for future research in interventions to prevent stillbirth.
In 1949, Priscilla White published Pregnancy Complicating Diabetes, which described the results and implications of a fifteen-year study about pregnant diabetic women. Published in the American Journal of Medicine, the article details possible causes of and ways to prevent the high fetal mortality rate associated with pregnant diabetic women. Diabetes is a disease in which the body's ability to produce or respond to the hormone insulin is impaired, and it can be particularly dangerous during pregnancies. In her article, White reported that prematurely delivering infants for diabetic pregnant women reduces infant and maternal mortality rates. Pregnancy Complicating Diabetes helped make premature delivery of infants the standard of care for diabetic pregnant women, and it has contributed to the increased survival rate of infants born from diabetic mothers from less than fifty percent in the 1940s to over ninety percent in 2017.
During the twentieth century, Norbert Freinkel studied hormones and diabetes in the US. Freinkel conducted many experiments that enabled him to determine the factors that influence hormones of the thyroid gland to bind to proteins and to determine the effects that those thyroid hormones have on surrounding tissues. Furthermore, Freinkel researched gestational diabetes, which is diabetes that occurs for the first time during a women’s pregnancy. That type of diabetes is caused by a change in the way a woman’s body responds to insulin, a hormone made in the body. Infants who are born from pregnant women with gestational diabetes can possess many different medical conditions such as type 2 diabetes, respiratory distress syndrome, and low blood sugar. Through his research on gestational diabetes, Freinkel found that all pregnant women go through metabolic changes, not just gestational diabetics.
Norbert Freinkel’s lecture Of Pregnancy and Progeny was published by the American Diabetes Association’s journal Diabetes in December of 1980. In the lecture, Freinkel argued that pregnancy changes the way that the female body breaks down and uses food. Through experiments that involved pregnant women as well as infants, Freinkel established the body’s maternal metabolism and how it affects both the mother and the infant. Freinkel’s main focus of research in the latter part of his life was diabetes, specifically in pregnant women. Diabetes occurs in around one to three percent of all pregnancies, which is 30,000 to 90,000 women a year in the US. Freinkel’s article indicates that pregnancy influences the metabolism in all pregnant females and that pregnancy complicated by diabetes is only an exaggeration of what occurs in all pregnant women. Subsequently, many doctors more closely monitored pregnant women and their blood sugar and insulin levels, as doctors were informed that all pregnant women have the capacity to become diabetic.
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.