(1) To assess the association between the duration of the third stage of labor and adverse maternal outcome after vaginal birth and (2) evaluate whether earlier manual placenta removal reduces this risk of adverse outcome.
PubMed/MEDLINE, EMBASE, ClinicalTrials.gov, Cochrane Library, Journals@Ovid and the WHO International Clinical Trials Registry from January 1st 2000-June 13 ^th 2023.
All studies that assessed adverse maternal outcome, defined as any maternal complication after vaginal birth, in relation to duration of the third stage of labor and timing of manual placenta removal.
Included studies were evaluated according the COSMOS-E (Conducting Systematic Reviews and Meta-Analyses of Observational Studies of Etiology) methodology. Pooled odds ratios with 95% confidence intervals were calculated. We assessed heterogeneity (I ² test); performed subgroup analyses; and calculated 95% prediction intervals.
To answer the first objective, 18 cohort studies were included. Assessed cut-offs of third stage were: 15, 30 and 60 minutes. Women with a third stage ≥15 minutes had an increased risk of postpartum hemorrhage compared to <15 minutes (Odds Ratio [OR] 5.55; 95%CI 1.74,17.72). For women without risk factors for postpartum hemorrhage, the OR was 2.20; 95%CI 0.75,6.49. Among women with a third stage ≥60 minutes versus <60 minutes, the OR was 3.72; 95%CI 2.36-5.89. Incidence of red blood cell transfusion was increased for a third stage ≥30 minutes versus <30 minutes (OR 3.23; 95%CI 2.26-4.61). Three studies assessed the timing of placenta removal and risk of adverse maternal outcome yet could not be pooled due to different outcome measures. One randomized controlled trial reported a significantly higher incidence of hemodynamic compromise in women with manual placenta removal at 15 versus 10 minutes (19.2%,30/156 6.4%,10/156) while two observational studies reported a lower risk of bleeding among women without manual placenta removal.
Although the risk of adverse maternal outcome after vaginal birth increases when the third stage of labor exceeds 15 minutes, there is no convincing evidence supporting a reduction of the third stage of labor by earlier manual removal of the placenta to reduce the incidence of adverse maternal outcome.