Comment: The quality of evidence is downgraded by study limitations.
A Cochrane review [Abstract] 2 included 28 studies involving a total of 2 786 women. Tocolytic parenteral beta stimulants vs placebo were effective in increasing cephalic presentations in labour and in reducing the number of caesarean sections. Failure to achieve a cephalic vaginal birth was less likely for women receiving a parenteral beta stimulant. No clear differences in fetal bradycardias were identified, although this was reported for only one study. Failed external cephalic version was less likely with beta stimulants. Perinatal mortality and serious morbidity were not reported. For other classes of tocolytic drugs (calcium channel blockers and nitric oxide donors), evidence was insufficient. Regional analgesia in combination with a tocolytic was more effective than the tocolytic alone for increasing successful versions (assessed by the rate of failed ECVs; average RR 0.61, 95% CI 0.43 to 0.86; 5 studies, n=409, moderate-quality evidence),
A meta-analysis 3 of external cephalic version -related risk included 84 studies with 12 955 version attempts. The pooled complication rate was 6.1% (95% CI 4.7 to 7.8), 0.24% for serious complications (95% CI 0.17 to 0.34) and 0.35% for emergency cesarean deliveries (95% CI 0.26 to 0.47). Complications were not related to external cephalic version outcome (OR 1.2 (95% CI 0.93 to 1.7).
Another Cochrane review [Abstract] 1 included 8 studies involving a total of 1 208. women. External cephalic version at term was associated with a significant reduction in non-cephalic births (RR 0.42, 95% CI 0.29 to 0.61; 8 trials, n=1 305) and caesarean section (RR 0.57, 95% CI 0.40 to 0.82; 8 studies, n=1 305). There was no significant effect on perinatal mortality (RR 0.39, 95% CI 0.09 to 1.64; 8 studies, n=1 305). There were no significant differences in the incidence of Apgar score ratings below seven at one minute (RR 0RR 0.67, 95% CI 0.32 to 1.37; 3 studies, n=168) or five minutes (RR 0.63, 95% CI 0.29 to 1.36; 5 studies, n=428), low umbilical artery pH levels, neonatal admission, nor time from enrolment to delivery.
| Outcome | Relative effect (95% CI) | Assumed risk -Placebo | Corresponding risk - Intervention (95% CI)= Betastimulant | Participants (studies) |
|---|---|---|---|---|
| Cephalic presentation at birth | 1.68 (1.14 to 2.48) | 255/1000 | 428/1000 (291 to 632) | 459(5) |
| Cephalic vaginal birth not achieved (Caesarean section + breech vaginal birth) | 0.75 (0.6 to 0.92) | 708/1000 | 531/1000(425 to 651) | 399(4) |
| Caesarean section | 0.77 (0.67 to 0.88) | 707/1000 | 544 /1000(474 to 622) | 742(6 ) |
| Failed external cephalic version | 0.7 (0.6 to 0.82) | 632/1000 | 442 per 1000(379 to 518) | 900(9) |
A retrospective cohort study 4 included 4117 participants. Of 1 263 (30.7%) attempted ECV; 509 (40.3%) resulted in successful versions. The composite perinatal morbidity and mortality outcome did not differ significantly between women who did and did not undergo attempted ECV (2.9% vs 2.5%, P=.46). The frequencies of neonatal intensive care unit admission (3.6% vs 3.3%, P=.53) and neonatal anemia (1.6% vs 1.2%, P=.36) were also similar. There continued to be no association between ECV attempt and composite perinatal morbidity and mortality outcome after adjustment for potential confounders (adjusted odds ratio 1.02, 95% CI 0.66 to 1.60).
Primary/Secondary Keywords