A Cochrane review included 13 studies with a total of 34 980 subjects. There was no difference in antenatal, obstetric and neonatal intervention or morbidity in screened versus control groups . Routine late pregnancy ultrasound was not associated with improvements in overall perinatal mortality.
| Outcome | Relative effect (95% CI) | Assumed risk -Control | Corresponding risk - Intervention=Routine ultrasound > 24 weeks (95% CI) | Participants (studies) |
|---|---|---|---|---|
| Perinatal mortality | RR 1.01 (0.67 to 1.54) | 6/1000 | 6 /1000 (4 to 9) | 30 675 (8) |
| Preterm delivery < 37 weeks' gestation | RR 0.96 (0.85 to 1.08) | 59/1000 | 57 /1000 (50 to 64) | 17 151 (2) |
| Induction of labour | RR 0.93 (0.81 to 1.07) | 238/1000 | 222/1000 (193 to 255) | 22 663 (6) |
| Caesarean section | RR 1.02 (0.97 to 1.09) | 139/1000 | 142 /1000 (135 to 152) | 27461 (6) |