Introduction: Occult or untreated gestational diabetes (GDM) is a well-known risk factor for adverse perinatal outcomes and may contribute to antepartum stillbirth. We assessed the impact of screening for GDM on the rate of antepartum stillbirths in non-anomalous pregnancies by conducting a population-based study in 974 889 women in Austria.
Material and methods: Our database was derived from the Austrian Birth Registry. Inclusion criteria were singleton live births and antepartum stillbirths ≥24+0 gestational weeks, excluding fetal congenital malformations, terminations of pregnancy and women with pre-existing type 1 or 2 diabetes. Main outcome measures were (a) overall stillbirth rates and (b) stillbirth rates in women at high risk of GDM (i.e., women with a body mass index ≥30 kg/m2 , history of previous intrauterine fetal death, GDM, previous macrosomic offspring) before (2008-2010, "phase I") and after (2011-2019, "phase II") the national implementation of universal GDM screening with a 75 g oral glucose tolerance test in Austrian pregnant women by 2011.
Results: In total, 940 373 pregnancies were included between 2008 and 2019, of which 2579 resulted in intrauterine fetal deaths at 33.51 ± 5.10 gestational weeks. After implementation of the GDM screening, a statistically significant reduction in antepartum stillbirth rates among non-anomalous singletons was observed only in women at high risk for GDM (4.10‰ [95% confidence interval (CI) 3.09-5.43] in phase I vs. 2.96‰ [95% CI 2.57-3.41] in phase II; p = 0.043) but not in the general population (2.76‰ [95% CI 2.55-2.99] in phase I vs. 2.74‰ [95% CI 2.62-2.86] in phase II; p = 0.845). The number needed to screen with the oral glucose tolerance test to subsequently prevent one case of (non-anomalous) intrauterine fetal death was 880 in the high-risk and 40 000 in the general population.
Conclusions: The implementation of a universal GDM screening program in Austria in 2011 has not led to any significant reduction in antenatal stillbirths among non-anomalous singletons in the general population. More international data are needed to strengthen our findings.
Keywords: epidemiology; gestational diabetes; high-risk pregnancy; intrauterine fetal death; public health; screening; stillbirth.
© 2022 The Authors. Acta Obstetricia et Gynecologica Scandinavica published by John Wiley & Sons Ltd on behalf of Nordic Federation of Societies of Obstetrics and Gynecology (NFOG).