Maternal mortality in Italy estimated by the Italian Obstetric Surveillance System

This study aimed to calculate Italy's first national maternal mortality ratio (MMR) through an innovative record-linkage approach within the enhanced Italian Obstetric Surveillance System (ItOSS). A record-linkage retrospective cohort study was conducted nationwide, encompassing all women aged 11-59 years with one or more hospitalizations related to pregnancy or pregnancy outcomes from 2011 to 2019. Maternal deaths were identified by integrating data from the Death Registry and national and regional Hospital Discharge Databases supported by the integration of findings from confidential enquiries conducted through active surveillance. Maternal Mortality Ratio (MMR), direct MMR (DMMR), and causes of maternal death are the study main outcomes. The MMR was found to be 8.4 per 100,000 live births (95% CI 7.5-9.3), significantly higher than the 3.9 per 100,000 (95% CI 3.3-4.5) calculated solely from the Death Registry, with a notable declining trend over the study period. Causes of death have been classified according to the 10th International Classification of Diseases. Within 42 days from pregnancy outcome, leading causes were obstetric haemorrhage, sepsis, and cardiovascular diseases. Late maternal deaths were primarily attributed to suicide, malignancies, and cardiovascular diseases. This integrated methodology provides a comprehensive understanding of maternal mortality trends and causes in Italy, offering valuable insights for countries utilizing or planning enhanced surveillance systems.