Table 3.

Summary of evidence for population-based screening for diabetes in early pregnancy among indigenous women in Australia, Canada, New Zealand and the United States

Screening criterion (no. publications)	Evidence statement	Quality of evidence for each statement and study references (H, high; M, moderate; L, low; VL, very low)	Country
1. Prevalence (n = 49)	Higher risk of undiagnosed T2DM in pregnancy and GDM	H 86	Aus, Can, NZ, US, Int
		M14,15,18,21,87–115,123,127
		L13,116–122,220
		VL126,145,169,221,222
Prevalence (trends) (n = 7)	Prevalence of GDM and T2DM in pregnancy is increasing	M21,125,167	Aus, Can, US, Int
		L [223,224]
		VL [225,226]
Natural history: risk for maternal development of DIP (n = 10)	Maternal birth-weight low and high (u-shaped association)	H 156	US
		M [227]
	Obesity	M99,123	Can, US Aus
		L 122
	Genetic variants	H [228]	US
	Thrifty genotype theory	VL2,145,161	Can, Int
	Thrifty phenotype theory	VL 160	US
Natural history: risk to woman during pregnancy and birth (n = 12)	Adverse birth outcomes (e.g. caesarean section and shoulder dystocia)	H 140	Aus, Can, NZ, US
		M92–95,111,113,129,133
	Increased risk of hospitalisation, associated with acute renal disease	M 136	Can, US
		L118,137
Natural history: maternal progression to T2DM (n = 8)	Non-pregnant women with impaired glucose intolerance have higher risk of T2DM than pregnant women with impaired glucose tolerance	H [229]	US
		L 13
	Increased risk of progressing from GDM to T2DM	M14,21,144	Can, US
		L 13
		VL 145
	Faster progression from GDM to T2DM	M96,112	Aus, Can
		L 13
	Progress from GDM to T2DM at a younger age	M 96	Aus
Natural history: risk to infant in pregnancy and birth (n = 21)	Increased risk of congenital abnormalities	H 131	Aus, US
		M15,108,132
		VL 138
	Increased risk of macrosomia	H128,139,140	Aus, Can, NZ, US
		M109,130,135,141–143
		L 128,230,231
	Increased risk NICU admissions or poor birth outcomes	M94,113,232	Aus, Can
		L [233]
		VL [234]
Natural history: long terms risks to infant (n = 31)	Increased risk of obesity	H146–148	Can, US
		L 128
		VL 149
	Increased risk of glucose intolerance	H148,150–152, M 153	US
	Increased risk of GDM and T2DM	H16,148,154–157	Can, US, Int
		M16,127,135,158,165,166,235
		L128,163,164
		VL2,159–162
	Increased risk renal disease	H [236,237]	US
2. Current screening practice and rates (n = 7)	GDM screening practice and rates is variable	M88,89,167,238	Aus, Can, NZ, US
		L13,168
		VL 169
	Highest risk women (e.g. obese women) may be less likely to be screened	M88,89	NZ, US
3. Preferences or values (n = 8)	Suggest resources be culturally adapted, programs provide blood sugar data and emphasize opportunity to save money with health diet	M 176	Can
	Prefer greater community involvement (especially midwives and elders) and recognise importance of family ties and cultural values	M 176	Can
		VL171,177
	Prefer group sessions and less direct advice (e.g. story-telling)	VL 171	Can
	Concern about weight gain in pregnancy but many barriers	VL 178	Can
	Many mixed understandings of risk and causes of DIP	M 172	Aus, Can, US
		L173,174
	Diet (grandmothers), exercise and stress (mothers) cause DIP	L 175	Can
4. Efficacy and cost (n = 3)	Screening more sensitive than risk factor analysis alone	H 180	US
	One-step WHO method more sensitive than two-step NDDG method	L 179	US
	HBA1C tests not appropriate screening tool among indigenous women	L 181	Int
5. Adequate treatment pathways (n = 6)	Integrated community care may improve self-monitoring	L 186	Aus
	Standards for diagnosis and treatment	VL 182	US
	Early screening needed to reduce risk of GDM to mother and baby	VL144,183,184	Aus, Can
	Insulin pumps may improve glycaemic control	L 185	NZ
6. Follow-up after pregnancy (n = 5)	Low rates of follow-up screening for T2DM after pregnancy for women diagnosed with GDM	M 14	Can, NZ, US
		L 13
		VL 188
	Registers may improve follow-up	VL 189	Can
	High rates of glucose intolerance in women with DIP followed up after pregnancy	L 188	NZ

DIP, diabetes in pregnancy; GDM, gestational diabetes mellitus; NDDG, National Diabetes Data Group; NICU, neonatal intensive care unit; T2DM, type 2 diabetes mellitus; WHO, World Health Organisation.