Category | No of study | No of case | No of control | SMD (95 % CI) | Z | p value | I2% | P het | |
---|---|---|---|---|---|---|---|---|---|
overall | 17 | 647 | 620 | 0.816 [0.411–1.122] | 3.94 | 0.000 | 91.0 | 0.000 | |
Gestational age at blood sampling | Before 24 weeks | 1 | 32 | 44 | -0.426 [-0.886–0.035] | 1.81 | 0.070 | - | - |
24-28 weeks | 10 | 390 | 386 | 0.561 [0.252–0.870] | 3.56 | 0.000 | 74.8 | 0.000 | |
After 28 weeks | 5 | 205 | 170 | 1.830 [0.580– 3.080] | 2.87 | 0.004 | 96.0 | 0.000 | |
Postpartum | 1 | 20 | 20 | -0.076 [-0.696–0.544] | 0.24 | 0.810 | - | - | |
Diagnostic criteria | ADA criteria | 8 | 347 | 310 | 0.205 [-0.063–0.472] | 1.50 | 0.134 | 61.7 | 0.011 |
Rigorous criteria | 9 | 300 | 310 | 1.388 [0.665–2.110] | 3.77 | 0.000 | 91.0 | 0.000 |