Are the changes in diagnostic criteria for gestational diabetes mellitus reflected in perinatal outcomes? A retrospective assessment

Benefits and harms associated with an increase in gestational diabetes diagnosis in Queensland, Australia: a retrospective cohort comparison of diagnosis rates, outcomes, interventions and medication use for two periods, 2011-2013 and 2016-2018, using a large perinatal database

OBJECTIVES

To assess benefits and harms arising from increasing gestational diabetes (GDM) diagnosis, including for women with normal-sized babies.

DESIGN, SETTING AND PARTICIPANTS

Diagnosis rates, outcomes, interventions and medication use are compared in a retrospective cohort study of 229 757 women birthing in public hospitals of the Australian State of Queensland during two periods, 2011-2013 and 2016-2018, using data from the Queensland Perinatal Data Collection.

OUTCOME MEASURES

Comparisons include hypertensive disorders, caesarean section, shoulder dystocia and associated harm, induction of labour (IOL), planned birth (PB), early planned birth <39 weeks (EPB), spontaneous labour onset with vaginal birth (SLVB) and medication use.

RESULTS

GDM diagnosis increased from 7.8% to 14.3%. There was no improvement in shoulder dystocia associated injuries, hypertensive disorders or caesarean sections. There was an increase in IOL (21.8%-30.0%; p<0.001), PB (36.3% to 46.0%; p<0.001) and EPB (13.5%-20.6%; p<0.001), and a decrease in SLVB (56.0%-47.3%; p<0.001). Women with GDM experienced an increase in IOL (40.9%-49.8%; p<0.001), PB (62.9% to 71.8%; p<0.001) and EPB (35.3%-45.7%; p<0.001), and a decrease in SLVB (30.01%-23.6%; p<0.001), with similar changes for mothers with normal-sized babies. Of women prescribed insulin in 2016-2018, 60.4% experienced IOL, 88.5% PB, 76.4% EPB and 8.0% SLVB. Medication use increased from 41.2% to 49.4% in women with GDM, from 3.2% to 7.1% in the antenatal population overall, from 3.3% to 7.5% in women with normal-sized babies and from 2.21% to 4.38% with babies less than the 10th percentile.

CONCLUSION

Outcomes were not apparently improved with increased GDM diagnosis. The merits of increased IOL or decreased SLVB depend on the views of individual women, but categorising more pregnancies as abnormal, and exposing more babies to the potential effects of early birth, medication effects and growth limitation may be harmful.

High proportion of overt diabetes mellitus in pregnancy and missed opportunity for early detection of diabetes at a tertiary care centre in Pakistan

Objectives

To determine the frequency of diabetes in pregnancy (DIP), namely pre-gestational, gestational (GDM) and overt diabetes mellitus (DM) in women registered for delivery.

Methods

A retrospective chart review of antenatal women registered between January 01 to August 31, 2017 was performed. Gestational age, diagnosis of DIP, glucose levels at diagnosis and other relevant data was extracted. The effect of various fasting blood glucose (FBG) thresholds for diagnosis of DIP was assessed.

Results

DIP was diagnosed in 21.8% women (pre-gestational: 2%, GDM: 81.2%, overt: DM: 16.8%). In early registrants, 30.2% were detected through screening. However, 55.3% of women registered late. Women with pre-gestational DM were older, had more miscarriages, and greater personal and family history of diabetes versus GDM and overt DM. Raising the diagnostic threshold of FBG from 92 mg/dl to 95 mg/dl missed three women (0.1%) and to 105 mg/dl, missed six women (0.2%).

Conclusion

We observed a high proportion of overt DM. In early registrants, almost one third of DIP was diagnosed in the first half of pregnancy, an opportunity missed in late registrants. Altering diagnostic thresholds of DIP affected only a small proportion of women.