Maternal Hyperglycaemia: Evaluating Outcomes and Accuracy of Multi-Modal Screening

Diabetes mellitus is becoming an increasingly common complication in pregnancy, driving a rise in gestational diabetes mellitus (GDM) worldwide. GDM affects approximately one in seven pregnancies globally and over 15% of pregnancies in South Africa, particularly in urban regions with a high burden of diabetes. Despite its growing prevalence, only a few studies over the past four decades have reported on hyperglycaemia first detected in pregnancy (HFDP), with rates ranging from 1.8% to 25.8%, reflecting differences in screening methods, diagnostic criteria, and laboratory measurements.

Hyperglycaemia in pregnancy is classified as either pre-gestational diabetes, including type 1 (T1DM) and type 2 diabetes (T2DM), or HFDP, which provides for GDM and overt diabetes first recognized during pregnancy. 

This study retrospectively evaluated 298 women with pre-gestational DM or HFDP between August 2019 and January 2021. Of these, 39.6% had GDM, 29.2% T2DM, 22.1% overt DM, and 9.1% T1DM. 

Key risk factors for GDM included family history, obesity, poor obstetric history, and previous macrosomia. HbA1c levels were highest in women with pre-gestational DM. Combining HbA1c ≥5.75% with fasting plasma glucose (FPG) 5.1–6.9 mmol/L provided the most accurate diagnosis (AUC 0.93). Postpartum, 21% of women with GDM developed DM, and 53% had impaired glucose tolerance, though only 48% attended follow-up.

These results underscore the need for early detection using combined FPG and HbA1c and improved postpartum follow-up to reduce long-term complications for mothers and their children.

Reference:

1. Manga J, Odell N, Khambule L, Harishun S, Mohamed F. Hyperglycaemia in pregnancy: outcomes and diagnostic accuracy of combined modalities. Clin Med. 2025;25(5):100495.; https://www.sciencedirect.com/science/article/pii/S1470211825002131