1. CDC. Pregnancy-related deaths. Atlanta, GA: US Department of Health and Human Services, CDC; 2019. https://www.cdc.gov/reproductivehealth/maternalinfanthealth/pregnancy-relatedmortality.htm
2. Pregnancy-related mortality in the United States, 2011–2013.;Creanga;Obstet Gynecol,2017
3. CDC. Pregnancy Mortality Surveillance System. Atlanta, GA: US Department of Health and Human Services, CDC; 2019. https://www.cdc.gov/reproductivehealth/maternalinfanthealth/pregnancy-mortality-surveillance-system.htm
4. Pregnancy-related mortality in the United States, 1998 to 2005.;Berg;Obstet Gynecol,2010
5. CDC. Birth data. Atlanta, GA: US Department of Health and Human Services, CDC; 2019. https://www.cdc.gov/nchs/nvss/births.htm