Meta-analysis of the effect of duration of labour on postpartum haemorrhage.

ABSTRACT

OBJECTIVES: To evaluate the relationship between stages of labour and the risk of postpartum haemorrhage (PPH) and provide evidence for clinical application. MATERIAL AND METHODS: Manual searches were undertaken, and computer searches of PubMed, MEDLINE, Web of Science, CNKI, Wanfang and Wipu databases with a search window from database creation to April 2022 were conducted to procure relevant studies on the relationship between labour phase and PPH. The articles included in this study were evaluated for quality, and RevMan 5.3 software was used for meta-analysis. RESULTS: Meta-analysis showed that the incidence of PPH in women with weak uterine contractions was 27.5%, compared with 18.1% in women with normal contractions [relative risk (RR) = 1.60; 95% confidence interval (CI) 1.38, 1.85; p < 0.01]. There was a statistically significant difference in the incidence of PPH in pregnant women with a prolonged second stage of labour (≥ 2 h) (34.5%) compared with those whose second stage of labour was normal in duration (15.9%) (RR = 0.20; 95% CI 0.15, 0.25; p < 0.01). The incidence of PPH was 52.1% in pregnant women with a prolonged third stage of labour (≥ 15 min) compared with 20.9% in those whose third stage of labour was of normal duration (RR = 3.53; 95% CI 2.75, 4.52; p < 0.01). The difference in the incidence of a prolonged third stage of labour in pregnant women with weak contractions compared with those with normal contractions was statistically significant (72.3% vs 15.5%) (RR = 0.47; 95% CI 0.35, 0.60; p < 0.01). CONCLUSIONS: Duration of labour is associated with the development of PPH, and the risk of PPH is increased in women with weak contractions or with a prolonged second or third stage of labour.