New guidelines for screening, diagnosing, and treating gestational diabetes – evaluation of maternal and neonatal outcomes in Finland from 2006 to 2012

Abstract

Introduction. In this study, we have assessed the changes in pregnancy outcomes following the implementation of national guidelines for gestational diabetes mellitus (GDM). These national guidelines changed the screening policy from risk-based to comprehensive screening. Material and methods. We designed a retrospective register-based cohort study based on the data from the Finnish Medical Birth Register and Hospital Discharge Register including 34 794 singleton births in 2006–2008 and 36 488 in 2010–2012. Maternal characteristics and pregnancy outcomes were analyzed. Results. Overall, 29.6% of mothers underwent an oral glucose tolerance test in 2006–2008 compared with 59.7% in 2010–2012. The prevalence of GDM increased from 7.2 to 11.3% and was highest among obese women (body mass index ≥30 kg/m2) (from 30.0 to 34.7%; p < 0.001). The proportion of insulin-treated women remained unchanged (12.5/12.3%; p = 0.70). The main pregnancy outcomes for the women with GDM were the increased usage of oxytocin (19.5/40.0%, p < 0.001), increased number of inductions (27.2/33.0%; p < 0.001) and reduced birthweight (mean ± SD: 3647 ± 575 g/3567 ± 575 g). Healthy and unscreened women displayed similar results. Children of both women with GDM and healthy screened women had fewer admissions to the neonatal intensive care unit (16.3%/12.1%; p < 0.001) and less asphyxia (11.3%/6.3%; p < 0.001). However, the rates of cesarean delivery (26.5%/25.4%, p = 0.31), resuscitation (2.6%/2.0%; p = 0.12), and perinatal mortality (1.2&/3.1&, p = 0.11) among women with GDM did not change, whereas the number of hypoglycemia cases increased (2.3%/5.2%; p < 0.001). Conclusions. In conclusion, glucose tolerance tests were performed twice as often as a result of the implementation of the national GDM guidelines, but this comprehensive screening practice did not improve pregnancy and neonatal outcomes.