To determine which risk factors are the strongest predictors of earlier diagnosis of gestational diabetes in women birthing at The Northern Hospital and how they compare to those recommended by the Australasian Diabetes in Pregnancy Society (ADIPS) for early glucose tolerance testing.
Women with GDM who gave birth at the Northern Hospital between 01/07/2017 and 31/10/2017 were studied retrospectively. Each patients’ risk factors for GDM as outlined by ADIPS were recorded and compared according to the timing of glucose tolerance test, being less than 24 weeks or 26-28 weeks gestation. Chi squared analysis and odds ratios were used to compare GDM risk factors between women who were diagnosed with GDM prior to 24 weeks gestation and those with diagnosis later.
Of 1298 births, 243 women (18.7%) were diagnosed with GDM. Multiparous women with previous GDM and women with a familial history of diabetes were 2.4 and 2.3 times more likely to have an early GDM diagnosis compared to women without previous or familial diabetes respectively (p < 0.01). The more risk factors a woman had, the more likely an early GDM diagnosis was made. When analysing risk factors recommended by ADIPS including previous macrosomia, high pre-pregnancy BMI, ethnicity, advanced maternal age, polycystic ovarian syndrome or the use of antipsychotic medications in pregnancy there was no difference between early (<24 weeks) and late (>24 weeks) GDM diagnosis. The mean number of risk factors for women with an early verses late diagnosis of GDM were 3.6 and 2.0 respectively.
A history of previous GDM or familial history of diabetes is the strongest predictor for an early diagnosis of diabetes in pregnancy. There is a cumulative effect of risk factors when assessing the overall GDM risk of pregnant women. There was no difference between early and late diagnosis of GDM for women with other risk factors outlined by ADIPS in this patient population.