Adverse outcome | Number of studies | Summary estimate OR (95% CI) | I2 (%) | Prediction interval |
Preterm birth | ||||
Adjusted | 5 | 1.90 (1.14 to 3.19) | 64.5 | 0.36 to 10.03 |
Unadjusted | 18 | 1.55 (1.21 to 1.99) | 61.1 | 0.72 to 3.35 |
Low birth weight | ||||
Adjusted | 4 | 1.48 (0.79 to 2.77) | 49.5 | 0.14 to 15.70 |
Unadjusted | 8 | 1.66 (1.12 to 2.48) | 72.7 | 0.51 to 5.38 |
Premature rupture of membrane | 9 | 1.41 (1.02 to 1.92) | 59.2 | 0.64 to 3.11 |
Spontaneous abortion* | 3 | NA | NA | NA |
Perinatal mortality | 9 | 2.16 (1.35 to 3.46) | 40.3 | 0.69 to 6.74 |
Ophthalmia neonatorum | 6 | 4.21 (1.36 to 13.04) | 58.0 | 0.17 to 104.58 |
*Each study had a different design, therefore it was not appropriate to report a summary estimate for this outcome.
NA, not applicable.