Background
Detecting HIP is complex, requiring a two-hour 75g OGTT at first antenatal presentation for women with risk-factors (early), and between 24–28 weeks' gestation (routine). Only 50% of rural and remote women in WA complete routine screening. Of those screened ~62% of HIP is missed due to preanalytical glucose measurement error. The ORCHID Study aims to improve HIP screening and management in rural and remote WA.
Methods
Setting: Kimberley ACCHOs introduced a first antenatal visit HbA1c (2017) and replaced fluoride-oxalate (FLOX) with fluoride-citrate (FC) tubes (2019). Retrospective audit (2018-2023): 1340 Kimberley ACCHO antenatal records (98% Aboriginal). Outcome measures: maternal characteristics, early HbA1c, OGTT (≥24-weeks’ gestation) pre- (T1) and post- (T2) FC tube implementation, HIP management, birth outcomes. Co-design management strategies: 47 research yarns (21 Aboriginal community members; 26 clinicians). Analysis: ADIPS 2025 OGTT diagnostic criteria; HbA1c rule-in threshold for HIP by OGTT (specificity >90%); FPG (mmol/L) triage: <4.7 low-risk; 4.7-5.2 indeterminate risk; ≥5.3 HIP. Aboriginal and non-Aboriginal researchers identified barriers and enablers for self-management, and acceptability of using technology and other resources.
Results
Audit: Most (86.7%) women presented <20-weeks gestation. Only 178/1132 women with HIP risk-factors had an early OGTT; 89 ≤14-weeks gestation;715 had an early HbA1c at 8.6±4.4 weeks gestation. An early HbA1c ≥5.7% had 94.9% specificity (95% CI 90.5-97.6) for HIP by routine OGTT (FC tubes). Only 378/830 eligible women completed a routine OGTT: 196 T1; 182 T2. The 1.9-fold T2 HIP increase (14.2% v 27.5%) was largely due to the fasting sample (39.3% v 78.1% of cases, P =0.001). Seven-fold more women were recommended pharmaceutical management (2.6% T1 v 17.6% T2, P <0.001). FPG triage would identify most of these women and reduce OGTTs (>50%). Co-design management themes: GDM screening is challenging; understanding GDM takes time; GDM management is individualised; Culturally safe holistic care is valued; care and support is provided by partners, extended family and friends; post-delivery it’s all about the baby.
Conclusions
Early and routine OGTT screening remains poor for remote Aboriginal women. Diagnostic equity could be addressed by reducing the early pregnancy HbA1c cut-point (5.7%) and removing OGTT confirmation. Addressing glycolysis improved identification of women requiring pharmaceutical intervention. FPG triaging would identify most of these women and reduce the burden of OGTTs. Pilot sites will host Aboriginal health navigators, who will provide support to Aboriginal women with GDM, from screening to 6-months post-partum.