Trend and risk Factors for Severe Peripartum Maternal morbidity - a population-based Cohort Study

While the rates of maternal mortality in developed countries have remained low in recent years, rates of severe maternal morbidity (SMM) are still increasing in high income countries. As a result, SMM is currently used as a measure of maternity care level. The aim of this study was to investigate the prevalence and risk factors of SMM surrounding childbirth.

A nested case-control study was performed between the years 2013-2018. SMM was defined as peripartum hospitalization involving intensive care unit (ICU). A comparison was conducted between parturient with SMM to those without, randomly matched for delivery mode and date of birth in a 1:1 ratio. Multivariable logistic regression models were used to evaluate the independent association between SMM and different maternal and pregnancy characteristics.

During the study period, 96,017 live births took place, of which 144 (1.5 per 1,000 live births-0.15%) involved SMM with ICU admissions. Parturient with SMM were more likely to have a history of 2 or more pregnancy losses (18.2% vs. 8.3%, p = 0.004), deliver preterm (48.9% vs. 8.8%, p < 0.001), and suffer from placenta previa (11.9% vs. 1.5%, p < 0.001), and/or placenta accreta (9.7% vs. 1.5%, p = 0.003). Several significant and independent risk factors for SMM were noted in the multivariable regression models: preterm delivery, history of ≥ 2 pregnancy losses, grand-multiparity, Jewish ethnicity, and abnormal placentation (previa or accreta).

SMM rates in our cohort were lower than reported in developed countries. An independent association exists between peripartum maternal ICU admissions and several demographic and clinical risk factors, including preterm birth and abnormal placentation.