Peripartum severe acute maternal morbidity in low-risk women: A population-based study

International audience; Background: Knowledge of severe acute maternal morbidity (SAMM) and its risk factors is constantly growing, but studies have rarely focused on the specific population of low-risk women. Aim: To estimate the prevalence and to identify subgroups at risk of peripartum SAMM in low-risk women Methods: From a population-based cohort-nested case-control study conducted in six French regions, i.e., 182 309 women who gave birth at ≥22 weeks in 119 maternity units, we selected women considered at low risk up to the end of pregnancy before labour according to the NICE guidelines and compared those experiencing peripartum SAMM (during birth and up to 7 days postpartum; n = 489) to a 2% random sample of women without peripartum SAMM from the same units (n = 1800). Risk factors for peripartum SAMM were identified by multivariable logistic regression. Findings: amongst low-risk women, the estimated rate of SAMM was 0.548/100 deliveries (95%CI 0.501-0.599). Severe obstetric haemorrhage was the main cause (83.6% of SAMM cases). Main risk factors for peripartum SAMM were primiparity (aOR 2.4, 95%CI 1.9-3.0), IVF pregnancy (aOR 1.8, 1.0-3.4), thirdtrimester anaemia (aOR 1.7, 1.3-2.3), being born out of Europe or Africa (aOR 1.9, 1.2-3.0). Conclusion: amongst women considered at low risk up to the end of pregnancy before labour, peripartum SAMM is rare but still exists. Knowledge of risk factors of SAMM in this population will inform the discussion on peripartum risks and the most appropriate place of birth for each woman.