Incidence of postpartum anaemia and risk factors associated with vaginal birth.

Background: Postpartum anaemia is a frequent and potentially preventable complication that has serious repercussions on health and maternal well-being.

Aim: Determine the incidence and perinatal risk factors associated with postpartum anaemia in women who gave birth vaginally.

Methods: An observational and analytical retrospective cohort study conducted at the Mancha-Centro Hospital during the 2010-2014 period. Data were collected from 2990 women who gave birth vaginally. The main outcome variable was postpartum anaemia for two cut-off points (haemoglobin (Hb) <11g/dL and <9g/dL at 24-h postpartum). Women with prepartum anaemia (<11g/dL) were excluded. It included a multivariate analysis by multiple linear regression.

Findings: 45% (1341) of women had postpartum levels of Hb <11g/dL, and 7.1% (212) of women had Hb <9g/dL. The most strongly associated risk factors with more severe anaemia (Hb <9g/dL) were episiotomy (OR 3.19. 95%CI: 2.10-4.84), first stage of labour >9h (OR 2.50. 95%CI: 1.58-3.94), primiparity (OR 2.50. 95%CI: 1.61-3.87) and previous caesarean section (OR 2.43. 95%CI: 1.51-3.90). The other independent risk factors for both Hb cut-off points were prolonged second stage of labour, instrumental birth, tearing>first degree, non-practice of active management and heavier birth weight of newborns.

Conclusion: Postpartum anaemia has a high incidence. The active management of third stage of labour, selective practice of episiotomies, and performing instrumental births only when strictly necessary are efficient measures to lower the incidence of postpartum anaemia.