TABLE 1.
Meta‐analysis I for the associations between interpregnancy interval and risk of adverse pregnancy and birth outcomes subsequent to live births.
| Adverse outcomes | No. of studies | <6 months | 6–11 months | 12–17 months | 18–23 months | 24–59 months | ≥60 months | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Pooled OR (95% CI) | I 2 (%) | Pooled OR (95% CI) | I 2 (%) | Pooled OR (95% CI) | I 2 (%) | OR | Pooled OR (95% CI) | I 2 (%) | Pooled OR (95% CI) | I 2 (%) | ||
| Birth outcomes | ||||||||||||
| Preterm birth | 37 studies 10 , 12 , 14 , 19 , 36 , 41 , 42 , 46 , 47 , 54 , 62 , 69 , 76 , 78 , 80 , 82 , 86 , 88 , 89 , 92 , 94 , 95 , 97 , 100 , 101 , 102 , 107 , 114 , 115 , 119 , 122 , 123 , 132 , 139 , 143 , 150 , 151 | 1.55 (1.47–1.63) | 92.2 | 1.16 (1.10–1.23) | 99.7 | 1.05 (1.01–1.09) | 98.5 | 1.00 | 1.05 (1.02–1.07) | 87.8 | 1.28 (1.20–1.35) | 96.9 |
| Small for gestational age | 24 studies 10 , 14 , 19 , 34 , 35 , 46 , 47 , 59 , 62 , 69 , 75 , 78 , 85 , 86 , 88 , 89 , 92 , 95 , 97 , 102 , 115 , 119 , 122 , 123 | 1.17 (1.12–1.23) | 79.9 | 1.05 (1.03–1.08) | 82.7 | 1.01 (0.99–1.03) | 43.9 | 1.00 | 1.06 (1.03–1.09) | 79.9 | 1.30 (1.22–1.40) | 94.8 |
| Low birthweight | 21studies 10 , 14 , 34 , 41 , 42 , 46 , 49 , 69 , 78 , 82 , 86 , 88 , 89 , 92 , 102 , 107 , 119 , 122 , 123 , 132 , 135 | 1.42 (1.31–1.55) | 88.7 | 1.10 (1.06–1.13) | 48.8 | 1.01 (0.99–1.04) | 10.6 | 1.00 | 1.08 (1.05–1.12) | 70.9 | 1.37 (1.27–1.48) | 96.3 |
| Fetal death | 8 studies 48 , 53 , 55 , 82 , 98 , 122 , 123 , 149 | 1.52 (1.36–1.70) | 0.0 | 1.05 (0.93–1.19) | 61.7 | 1.02 (0.80–1.30) | 21.0 | 1.00 | 1.00 (0.97–1.03) | 27.6 | 1.14 (1.04–1.24) | 86.7 |
| Birth defects | 6 studies 8 , 10 , 62 , 73 , 79 , 87 | 1.12 (1.04–1.22) | 55.7 | 1.03 (0.97–1.10) | 56.0 | 1.01 (0.95–1.07) | 22.7 | 1.00 | 1.05 (1.02–1.09) | 0.0 | 1.08 (1.02–1.14) | 0.0 |
| Cleft lip with and without cleft palate | 4 studies 8 , 60 , 73 , 79 | 1.04 (0.68–1.60) | 0.0 | 1.20 (0.88–1.66) | 15.5 | 1.03 (0.74–1.45) | 0.0 | 1.00 | 1.28 (1.04–1.58) | 21.5 | — | — |
| Early neonatal death | 3 studies 48 , 62 , 122 | 1.32 (1.04–1.67) | 46.4 | 1.19 (1.03–1.36) | 32.0 | — | — | 1.00 | 1.01 (0.88–1.18) | 42.6 | 1.17 (1.06–1.28) | 0.0 |
| Large for gestational age | 3 studies 62 , 85 , 97 | 0.81 (0.78–0.84) | 18.1 | 0.91 (0.82–1.01) | 95.1 | — | — | 1.00 | 1.03 (0.93–1.13) | 97.1 | 0.94 (0.74–1.20) | 99.1 |
| Pregnancy outcomes | ||||||||||||
| Preeclampsia | 7 studies 13 , 82 , 89 , 107 , 109 , 112 , 120 | 0.96 (0.87–1.06) | 55.1 | 0.91 (0.81–1.03) | 85.1 | 0.94 (0.83–1.06) | 74.3 | 1.00 | 1.08 (0.99–1.18) | 89.5 | 1.35 (1.18, –1.54) | 95.2 |
| Gestational diabetes | 5 studies 89 , 99 , 100 , 107 , 120 | 1.07 (0.87–1.32) | 93.4 | 0.92 (0.91–0.94) | 0.0 | 0.98 (0.96–0.99) | 0.0 | 1.00 | 1.15 (1.08–1.22) | 16.8 | 1.37 (1.26–1.48) | 41.5 |
| Premature rupture of fetal membranes | 4 studies 96 , 107 , 120 , 123 | 1.56 (1.29–1.88) | 81.7 | 1.03 (0.96–1.11) | 0.0 | 1.02 (0.94–1.11) | 0.0 | 1.00 | 1.11 (0.96–1.28) | 80.0 | 1.53 (1.07–2.20) | 92.1 |
| Pregnancy‐induced hypertension | 3 studies 100 , 107 , 123 | 1.07 (0.77–1.49) | 66.9 | 0.93 (0.91–0.95) | 0.0 | 0.95 (0.93–0.96) | 0.0 | 1.00 | 1.04 (0.78–1.39) | 0.0 | 1.47 (1.01–2.14) | 28.4 |
| Anemia, maternal | 2 studies 109 , 120 | — | — | — | — | — | — | 1.00 | 1.09 (0.89–1.33) | 28.1 | 0.98 (0.76–1.25) | 14.3 |
| Postpartum hemorrhage | 2 studies 109 , 120 | — | — | — | — | — | — | 1.00 | 1.00 (0.85–1.17) | 40.2 | 0.89 (0.78–1.02) | 0.0 |
| Miscarriage | 2 studies 11 , 53 | — | — | 1.00 (0.80–1.24) | 0.0 | — | — | 1.00 | 1.23 (1.08–1.42) | 0.0 | — | — |
Abbreviations: CI, confidence interval; OR, odds ratio.