WHO criteria for diabetes in pregnancy: a retrospective cohort

Abstract

Background: Recognizing that hyperglycemia in pregnancy can impact both individually a patient's health and collectively the healthcare system and that different levels of hyperglycemia incur different consequences, we aimed to evaluate the differences and similarities between patients who met the diagnostic criteria for gestational diabetes mellitus (GDM) or diabetes in pregnancy (DIP) according to the World Health Organization diagnostic criteria based on the 75 g oral glucose tolerance test (OGTT).

Methods: This retrospective study included a cohort of 1064 women followed-up at the Gestational Diabetes Unit of Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo (Sao Paulo, Brazil). Patients were classified into GDM and DIP groups, according to their OGTT results. Their electronic charts were reviewed to obtain clinical and laboratory data for all participants.

Results: Women in the DIP group had a higher pre-pregnancy body mass index (30.5 vs 28.1 kg/m², odds ratio [OR] 1.07, 95% confidence interval [CI] 1.02-1.11), more frequently experienced GDM in a previous pregnancy (25% vs. 11%, OR 2.71, 95% CI 1.17-6.27), and were more likely to have chronic hypertension (43.1% vs. 23.5%, OR 2.46, 95% CI 1.47-4.11), a current twin pregnancy (10.8% vs. 2.9%, OR 4.04, 95% CI 1.70-9.61), or require insulin (46.1% vs. 14.3%, OR 5.14, 95% CI 3.06-8.65) than those in the GDM group. Patients in the DIP group also had a higher frequency of large-for-gestational-age infants (12.3% vs. 5.1%, OR 2.78, 95% CI 1.23-6.27) and abnormal postpartum OGTT (45.9% vs. 12.6%, OR 5.91, 95% CI 2.93-11.90) than those in the GDM group. Nevertheless, in more than half of the DIP patients, glucose levels returned to normal after birth.

Conclusions: Diabetes in pregnancy is associated with an increased risk of adverse perinatal outcomes but does not equate to a diagnosis of diabetes post-pregnancy. It is necessary to identify and monitor these women more closely during and after pregnancy. Keeping patients with hyperglycemia in pregnancy engaged in healthcare is essential for accurate diagnosis and prevention of complications related to abnormal glucose metabolism.

Keywords: Diabetes in pregnancy; Gestational diabetes mellitus; Glucose Tolerance Test; World Health Organization.

Fig. 1

Probability of abnormal postpartum oral glucose tolerance test (OGTT) according to patient age and hyperglycemia classification during pregnancy (gestational diabetes mellitus [GDM] or diabetes in pregnancy [DIP]). The model also takes into account whether the patient’s blood sugar levels were managed by diet alone (diet) or whether insulin was required (+insulin). An abnormal result included diagnoses of impaired fasting glucose, impaired glucose tolerance, and diabetes mellitus