Table 2.
Outcome, study design | Analysis | Number of studies, design | Sample size for outcome | I2 % | Summary OR (95% CI) |
Preterm birth | Unadjusted, meta-analysis | 7 5 cohort, 2 case–control |
4573 | 0 | 1.91 (1.29 to 2.81) |
Adjusted, meta-analysis | 2 1 cohort, 1 case–control |
NR | 0 | 2.34 (1.17 to 4.71) | |
Spontaneous abortion | Unadjusted, meta-analysis | 6 4 cohort, 2 case–control |
2837 | 0 | 1.00 (0.53 to 1.89) |
Adjusted | 1 case–control | 216 | NA | 0.9 (0.2 to 3.8)* | |
Premature rupture of membranes | Unadjusted | 1 cohort | 871 | NA | 7.62 (0.40 to 145.86) |
Low birth weight | Unadjusted | 1 cohort | 81 | NA | 1.07 (0.02 to 10.39) |
Perinatal death | Unadjusted | 1 cohort | 872 | NA | 38.42 (1.45 to 1021.43) |
Unadjusted | 1 case–control | 725 | NA | 1.07 (0.49 to 2.36) |
*Adjusted OR reported to one decimal place, as in the publication, reference 25.
NA, not applicable; NR, not reported.