Database.

The objective of this study is to describe the causes of maternal deaths and estimate the magnitude of maternal mortality in the state of Goiás, considering the underreporting of maternal deaths from 2016 to 2021. This is a descriptive study that linked data from the Mortality Information System (SIM in Portuguese) and the Live Birth Information System (SINASC in Portuguese) using a linkage procedure. The aim was to identify maternal deaths and their causes and calculate the Maternal Mortality Ratio (MMR). A total of 417 maternal deaths were officially reported in Goiás from 2016 to 2021. Among these, 291 matches were identified between the systems, including 239 cases where the declared underlying cause was maternal death, 17 with presumed causes, and 35 with other causes. The leading causes of death for maternal deaths, deaths with presumed causes, and other deaths were, respectively: other obstetric conditions not elsewhere classified; symptoms, signs, and abnormal clinical and laboratory findings not elsewhere classified; and certain infectious and parasitic diseases. Considering only declared maternal deaths, the MMR ranged from 55.79 (2016) to 137.46 (2021) deaths per 100,000 live births (LB), reflecting a 146% increase. Considering the inclusion of deaths identified through linkage, the MMR ranged from 55.79 (2016) to 157.42 (2021) deaths per 100,000 LB, representing an 182% increase. The underestimation of MMR values was adjusted compared to direct estimates using the SIM and SINASC systems. This indicates that maternal mortality is higher than reflected in official statistics.