Australia and New Zealand (NZ) have maintained different oral glucose tolerance test (OGTT) cutoffs to diagnose gestational diabetes (GDM). We wanted to determine whether there were different pregnancy outcomes between Liverpool Hospital (LH) in Australia and Waikato Hospital (WH) in NZ depending whether they met the NZ GDM OGTT diagnostic criteria (NZGDM).
NZGDM has higher OGTT criteria with fasting ≥5.5mmol/L, 2-hour ≥9.0mmol/L. LH followed Australian Diabetes in Pregnancy Society 1997 and 2014 GDM diagnostic criteria with lower cut-offs (fasting ≥5.5&≥5.1mmol/L;2-hour ≥8.0&≥8.5mmol/L). Two groups from LH were defined as NZGDM OGTT positive or negative. We devised a composite outcome of macrosomia, perinatal death, preterm delivery, neonatal hypoglycaemia and phototherapy.
There were 7,518 pregnancies.
|
GDM Grouping according to NZGDM |
Waikato NZGDM positive (n=2,278) |
Liverpool NZGDM positive (n=2,403) |
Liverpool NZGDM negative (n-2,837) |
|
|
MATERNAL OUTCOMES |
|
|
|
|
|
HbA1c at diagnosis (%) |
5.49(95%CI: 5.46–5.52) |
5.35(95%CI: 5.37–5.41) |
5.25(95%CI: 5.22–5.27) |
<0.001 |
|
HbA1c during 3rd trimester(%) |
5.51(95% CI: 5.49–5.54) |
5.53(95%CI: 5.50–5.57) |
5.47(95%CI: 5.43–5.51) |
0.046 |
|
Metformin treatment |
277(12.2%) |
156(6.5%) |
251(8.8%) |
<0.001 |
|
Short-acting insulin treatment |
797(35.0%) |
870(36.2%) |
639(22.5%) |
<0.001 |
|
Long-acting insulin treatment |
700(30.7%) |
998(41.5%) |
706(24.9%) |
<0.001 |
|
Hypertension in pregnancy |
85(3.7%) |
143(6.0%) |
123(4.3%) |
<0.001 |
|
NEONATAL OUTCOMES |
|
|
|
|
|
Delivery weeks |
38.10(95%CI: 38.02–38.17) |
38.59(95%CI: 38.52–38.67) |
38.70(95%CI: 38.63–38.77) |
<0.001 |
|
Preterm delivery(<37weeks) |
214(9.4%) |
211(8.8%) |
229(8.1%) |
0.295 |
|
Birth weight(g) |
3371.8(95%CI: 3345.7–3397.1) |
3318.6(95%CI: 3294.3–3343.0) |
3319.5(95%CI: 3297.3–3341.7) |
0.005 |
|
Macrosomia(>4500g) |
62(2.7%) |
42(1.7%) |
28(1.0%) |
<0.001 |
|
Normal vaginal delivery |
1,306(57.3%) |
971(40.4%) |
1,218(42.9%) |
<0.001 |
|
Caesarean delivery–emergency indication |
415(18.2%) |
269(11.2%) |
301(10.6%) |
<0.001 |
|
Caesarean delivery–elective indication |
333(14.6%) |
434(18.1%) |
509(17.9%) |
0.004 |
|
Neonatal intensive care admission |
485(21.3%) |
205(8.5%) |
286(10.1%) |
<0.001 |
|
Neonatal hypoglycaemia |
660(29.0%) |
658(27.4%) |
538(19.0%) |
<0.001 |
|
Major congenital abnormalities |
35(1.5%) |
21(0.9%) |
21(0.7%) |
0.034 |
|
Minor congenital abnormalities |
38(1.7%) |
81(3.4%) |
83(2.9%) |
0.002 |
|
Phototherapy for neonatal jaundice |
115(5.0%) |
19(0.8%) |
13(0.5%) |
<0.001 |
|
Perinatal death |
5(0.2%) |
24(1.0%) |
20(0.7%) |
0.008 |
|
Composite Outcome Odds Ratio |
859(37.7%) 1.00 |
814(33.9%) 0.865(95%CI: 0.752–0.995) |
687(24.2%) 0.559(95%CI: 0.486–0.643) |
<0.001 |
Women who were NZGDM negative had less pregnancy complications than NZGDM positive women. Women at LH had less pregnancy complications than women at WH in spite of comparable HbA1c in the third trimester.