Prevalence of gestational diabetes and recourse to postpartum oral glucose tolerance test in the Autonomous Province of Trento (Italy)

Abstract

Objective: The occurrence of gestational diabetes (GDM) is increasing worldwide, and such a diagnosis is important for women's health beyond pregnancy. Therefore, many guidelines suggest the re-evaluation of glucose tolerance with a postpartum oral glucose tolerance test (OGTT) in women with GDM. This study reports the prevalence of GDM and the use of a postpartum OGTT in women assisted at maternity units in the Autonomous Province of Trento in the years 2017-2018, investigating the socio-demographic and health-care variables that can facilitate access to the test.

Study design: For the diagnosis of GDM, the International Association of Diabetes and Pregnancy Study Group criteria were used. The Birth Assistance Certificate and the Hospital Information System were used to retrieve clinical and socio-demographic data. Univariate and multivariate analyses were performed to evaluate the stratification of the use of a postpartum OGTT.

Results: In total, 8,308 pregnant women were assisted at the maternity units in Trento. There were 532 recorded cases of GDM (266 cases per year) and the overall average prevalence was 6.4 % (95 % CI, 5.90-6.90), 4.9 % of whom were Italian (95 % CI, 4.38-5.42) and 10.4 %, foreigners (95 % CI, 9.13-11.67). 135 women diagnosed with GDM and residing in Trento out of 513 were evaluated using a postpartum OGTT (26.3%, CI 95% 22.50-30.10), with pathological results in 61 cases (45.2%). In the multivariate analyses, insulin therapy during pregnancy, delivery at a third-level birth point, and a discharge letter informing of the presence of GDM and of the need for a postpartum OGTT were independent factors associated with the probability of carrying out a postpartum OGTT.

Conclusions: The prevalence of GDM in our study is lower than in previous Italian studies; however, it is consistent with European data. The proportion of women who were assessed using the postpartum OGTT is lower than that reported by previous studies. The health-care factors seem predominant among the socio-demographic characteristics of the cases in influencing access to the test. The awareness of women, the sharing of guidelines among the different sectors of the health system, and an optimal management of the discharge from the birth point are critical in ensuring an optimal follow-up in women with GDM.

Keywords: Discharge letter; Gestational diabetes; Health-care variables; Postpartum OGTT; Prevalence; Socio-demographic variables.