Table 1.
Meta-analysis results for primary pregnancy outcomes.
| Outcome | Included studies | Number of studies | Number of patients | RR or OR (95%CI) | P-value | I2 | Model |
|---|---|---|---|---|---|---|---|
| Preterm delivery | all RCTs | 8 | 2443 | 0.56 (0.43, 0.73) | < 0.001 | 0% | Fix |
| RCTs with low and moderate risk of bias | 3 | 895 | 0.46 (0.19, 1.09) | 0.080 | 65% | Random | |
| all cohort studies | 11 | 8609 | 0.57 (0.37, 0.87) | 0.009 | 69% | Random | |
| cohort studies with low and moderate risk of bias | 3 | 1760 | 1.21 (0.78, 1.87) | 0.390 | 0% | Fix | |
| Miscarriage | all RCTs | 7 | 2254 | 0.43 (0.32, 0.57) | < 0.001 | 0% | Fix |
| RCTs with low and moderate risk of bias | 2 | 706 | 0.36 (0.13, 1.03) | 0.060 | 38% | Fix | |
| all cohort studies | 9 | 7406 | 0.55 (0.45, 0.68) | < 0.001 | 30% | Fix | |
| cohort studies with low and moderate risk of bias | 2 | 1238 | 0.47 (0.33, 0.68) | < 0.001 | 0% | Fix | |
| Gestational hypertension | all RCTs | 4 | 2011 | 0.63 (0.47, 0.84) | 0.002 | 42% | Fix |
| RCTs with low and moderate risk of bias | 1 | 677 | 0.91 (0.58, 1.43) | 0.690 | 0% | Fix | |
| all cohort studies | 9 | 8353 | 0.75 (0.65, 0.87) | < 0.001 | 0% | Fix | |
| cohort studies with low and moderate risk of bias | 2 | 1667 | 0.80 (0.52, 1.22) | 0.310 | 0% | Fix | |
| Preeclampsia | all RCTs | 1 | 677 | 1.10 (0.61, 1.97) | 0.760 | 0% | Fix |
| RCTs with low and moderate risk of bias | 1 | 677 | 1.10 (0.61, 1.97) | 0.760 | 0% | Fix | |
| all cohort studies | 0 | 0 | NA | NA | NA | NA | |
| cohort studies with low and moderate risk of bias | 0 | 0 | NA | NA | NA | NA | |
| Gestational diabetes | all RCTs | 4 | 1021 | 0.80 (0.51, 1.25) | 0.320 | 34% | Fix |
| RCTs with low and moderate risk of bias | 1 | 677 | 1.13 (0.65, 1.97) | 0.660 | 0% | Fix | |
| all cohort studies | 9 | 5004 | 0.56 (0.36, 0.89) | 0.010 | 75% | Random | |
| cohort studies with low and moderate risk of bias | 2 | 1667 | 0.82 (0.25, 2.69) | 0.750 | 93% | Random |
RCTs, randomized controlled trials; RR, relative risk; OR, odds ratio; CI, confidence interval; I2, statistical heterogeneity; NA, not applicable since no studies were included; According to the pre-defined rules, the meta-analysis results with gray background were used to draw conclusions for each outcome.