Table 1

Study population characteristics by GDM diagnosis and time, within the GDM diagnosed group

Total 2006–2015No GDM by yearGDM by year
No GDM (%)
(n=806 155)
GDM (%)
(n=71 740)
Difference (95% CI)*2006 (%)
(n=78 941)
2015 (%)
(n=76 555)
Rate difference (95% CI)†2006 (%)
(n=4833)
2015 (%)
(n=11 254)
Rate difference (95% CI)†
Mother’s region of birth
 Australia and New Zealand71.350.3−20.9 (−21.3 to −20.6)75.668.6−8.4 (−8.8 to −8.1)54.950.1−5.7 (−7.0 to −4.4)
 Oceania and Antarctica1.22.51.2 (1.1 to 1.4)1.51.0−0.5 (−0.6 to −0.4)3.52.2−1.4 (−1.8 to −1.0)
 North-East Asia4.910.45.6 (5.3 to 5.8)3.25.63.3 (3.1 to 3.4)7.89.72.6 (1.8 to 3.4)
 South-East Asia5.110.95.8 (5.5 to 6.0)4.84.90.2 (0.0 to 0.3)12.110.1−2.3 (−3.1 to −1.5)
 Central Asia0.40.60.2 (0.1 to 0.2)0.40.50.1 (0.0 to 0.1)0.60.70.3 (0.1 to 0.5)
 Southern Asia4.312.17.9 (7.6 to 8.1)2.45.93.9 (3.8 to 4.1)7.214.88.6 (7.7 to 9.4)
 Europe5.64.6−1.0 (−1.2 to −0.9)5.35.90.5 (0.3 to 0.7)4.94.4−1.0 (−1.5 to −0.5)
 North Africa and Middle East4.05.51.5 (1.3 to 1.7)3.94.10.3 (0.2 to 0.5)6.05.2−1.0 (−1.5 to −0.4)
 Sub-Saharan Africa1.41.40.0 (−0.1 to 0.1)1.21.40.2 (0.1 to 0.3)1.31.2−0.1 (−0.4 to 0.2)
 North America0.80.6−0.2 (−0.3 to −0.1)0.80.90.2 (0.1 to 0.2)0.50.60.1 (−0.1 to 0.3)
 Latin America and Caribbean0.91.00.1 (0.0 to 0.1)0.91.10.2 (0.2 to 0.3)1.10.90.0 (−0.3 to 0.2)
Resides in:
 Major city77.784.87.1 (6.8 to 7.4)76.878.32.0 (1.7 to 2.4)85.083.8−1.6 (−2.5 to −0.7)
 Most advantaged SES area18.114.4−3.7 (−3.9 to −3.4)18.217.9−0.1 (−0.4 to 0.1)14.513.2−1.8 (−2.6 to −0.9)
 Age 35+22.133.911.8 (11.5 to 12.2)20.621.90.6 (0.2 to 0.9)34.431.4−5.3 (−6.5 to −4.1)
 Smoked during pregnancy11.18.0−3.1 (−3.3 to −2.9)13.28.7−5.1 (−5.4 to −4.9)9.67.3−2.9 (−3.5 to −2.2)
 Chronic disease2.33.31.0 (0.9 to 1.1)3.22.6−0.4 (−0.6 to −0.3)3.93.60.2 (−0.2 to 0.7)
 Nulliparous43.242.1−1.1 (−1.5 to −0.7)41.744.23.6 (3.3 to 4.0)37.942.64.4 (3.1 to 5.7)
 Previous cesarean section14.718.84.1 (3.8 to 4.4)13.015.12.0 (1.8 to 2.3)16.019.63.4 (2.4 to 4.4)
 Placental issue1.72.10.4 (0.3 to 0.5)1.61.70.1 (0.0 to 0.2)2.12.20.2 (−0.2 to 0.6)
 Vertex presentation96.295.7−0.5 (−0.6 to −0.3)95.796.40.7 (0.5 to 0.8)94.996.20.9 (0.4 to 1.4)
 PROM10.29.5−0.7 (−0.9 to −0.5)8.611.02.2 (2.0 to 2.5)8.69.71.4 (0.7 to 2.1)
 ART3.04.01.0 (0.8 to 1.1)2.43.51.1 (1.0 to 1.3)3.13.90.7 (0.2 to 1.2)
  • *Percentage difference in total ‘No GDM’ and ‘GDM’ percentages.

  • †Rate difference, average 10-year linear change estimated using linear regression across 2006–2015.

  • ART, assisted reproductive technology; GDM, gestational diabetes mellitus; PROM, prelabor rupture of membranes; SES, socioeconomic status.