Table 1.
Summary of findings.
| Outcome | No of studies | Total number of participants | Idiopathic polyhydramnios group events per total n/N (%) | Non-idiopathic polyhydramnios group events per total n/N (%) | RR (95% CI) [random effect model-inverse variance method] | I2 | τ2 |
|---|---|---|---|---|---|---|---|
| Antenatal complications (n = 3) | |||||||
| Preterm birth | 15 | 304,563 | 901/8392 (10.7%) | 18,830/296,171 (6.3%) | 1.96 [1.35, 2.86] | 92% | 0.42 |
| PPROM | 6 | 59,176 | 151/2248 (6.7%) | 2775/56,928 (4.8%) | 1.27 [0.50, 3.25] | 96% | 1.14 |
| PIH/PE | 11 | 147,852 | 133/3364 (3.9%) | 4439/144,488 (3%) | 1.01 [0.81, 1.28] | 16% | 0.02 |
| Intrapartum/peripartum complications (n = 11) | |||||||
| Malpresentation | 15 | 212,008 | 294/4258 (6.9%) | 7793/207,750 (3.7%) | 1.82 [1.42, 2.35] | 54% | 0.10 |
| Transverse lie | 2 | 1160 | 33/559 (5.9%) | 13/601 (2.2%) | 2.64 [1.29, 5.42] | 6% | 0.03 |
| Breech | 2 | 30,974 | 27/792 (3.4%) | 1083/30,182 (3.6%) | 1.34 [0.52, 3.46] | 70% | 0.33 |
| Labour induction | 10 | 326,212 | 2387/8866 (28.9%) | 49,283/317,346 (17.6%) | 1.53 [1.18, 2.00] | 95% | 0.14 |
| Epidural analgesia | 3 | 69,100 | 880/1257 (70.0%) | 43,410/67,843 (63.9%) | 1.08 [0.98, 1.18] | 81% | 0.01 |
| Cephalopelvic disproportion | 5 | 2235 | 44/946 (4.7%) | 26/1289 (2.0%) | 2.43 [1.02, 5.84] | 53% | 0.48 |
| Cord prolapse | 11 | 151,925 | 43/3797 (1.1%) | 343/148,128 (0.2%) | 6.5 [4.68, 9.04] | 0% | 0.00 |
| Placental abruption | 9 | 159,019 | 64/3122 (2.0%) | 540/155,897 (0.3%) | 3.20 [2.20, 4.65] | 2% | 0.01 |
| Shoulder dystocia | 5 | 75,047 | 21/1054 (2%) | 240/73,993 (0.3%) | 3.52 [2.08, 5.96] | 0% | 0 |
| Caesarean section | 31 | 465,744 | 3301/12,134 (27.2%) | 95,945/453,610 (21.1%) | 1.60 [1.39, 1.84] | 95% | 0.12 |
| PPH | 12 | 172,249 | 220/3154 (6.9%) | 5158/169,095 (3.0%) | 1.98 [1.22, 3.22] | 84% | 0.48 |
| Neonatal outcomes (n = 7) | |||||||
| Low birth weight | 7 | 304,434 | 267/6754 (4.0%) | 12,225/297,680 (4.1%) | 1.21 [0.74, 1.98] | 82% | 0.31 |
| Macrosomia | 20 | 546,459 | 2001/15,586 (12.8%) | 27,506/530,873 (5.1%) | 2.68 [2.43, 2.95] | 48% | 0.01 |
| 1 min APGAR | 10 | 344,214 | 492/7141 (6.9%) | 10,893/337,073 (3.2%) | 2.14 [1.48, 3.10] | 80% | 0.24 |
| 5 min APGAR | 17 | 447,062 | 209/10,501 (2.0%) | 5785/436,561 (1.3%) | 3.00 [1.23, 7.35] | 95% | 2.87 |
| NICU admission | 22 | 209,409 | 672/4690 (14.3%) | 20,863/204,719 (10.1%) | 1.62 [1.11, 2.37] | 90% | 0.57 |
| Stillbirth | 13 | 135,771 | 74/3268 (2.2%) | 221/132,503 (0.1%) | 4.75 [2.54, 8.86] | 9% | 0.10 |
| Perinatal mortality | 18 | 261,038 | 187/4671 (3.4%) | 723/256,367 (0.3%) | 4.75 [2.67, 8.48] | 37% | 0.37 |
1 m: 1 min/5 m: 5 min; APGAR appearance, pulse, grimace, activity, and respiration score; IP idiopathic polyhydramnios; NICU neonatal intensive care unit; PIH/PE pregnancy induced hypertension/pre-eclampsia; PPH post-partum haemorrhage; PPROM preterm premature rapture of membranes.