Did You Know…that the vaginal microbiome is connected to maternal mortality in Black women?

Did You Know…that the vaginal microbiome is connected to maternal mortality in Black women?

April 2023

Chief Science Officer, Beth DuPriest, PhD
This month, in honor of Black Maternal Awareness Week,  Chief Science Officer Beth DuPriest, PhD discusses the rise of mortality rates, especially among Black maternal women, the factors driving these adverse health outcomes, and the call to action to more proactively make progress on this important health crisis.


Black women in the US face a 3x higher risk of death during and after pregnancy than White women do1. Recently-released data for 2021 show death rates were 89% higher than in 2018 – almost double!2 Although the COVID-19 pandemic is responsible for some of that increase, rates have been rising in the US for nearly 30 years3. While most pregnancy-related deaths are due to cardiovascular complications (cardiomyopathy, hemorrhage, clotting, etc.), maternal infections are the highest cause of maternal death just prior to, during, and in the six weeks after delivery3. A plurality of maternal infections stem from genitourinary infections4; others originate from wound infections such as from C-sections, episiotomies, or perineal tears. Respiratory, digestive, skin, and other infections are also contributors.

Distribution of Contributing Factors among Pregnancy-related Dealths
Source: Report from Nine Maternal Mortality Committees

The elevated risk of death in Black women persists across all related socioeconomic factors. The disparity is even greater, perhaps surprisingly, in college-educated women: education is quite protective for White women, but not nearly as much for Black women1. While we don’t yet understand why this is true, the data seem to suggest that there are both biological and social determinants of the disparity in pregnancy-related mortality between Black and White women in the US.

In terms of biology, the vaginal microbiome is much more likely to be a polymicrobial biome with lower levels of protective Lactobacillus species and higher levels of anaerobic pathogens in Black women than in White women5. This represents an unhealthy vaginal community state which is associated with a variety of poor pregnancy outcomes for the mother, including (preterm) premature rupture of membranes6, chorioamnionitis7, and endometritis, not to mention adverse neonatal outcomes like low birthweight and early-onset neonatal infection/sepsis. Unfortunately, there are no clear data yet on how improving the vaginal microbiome may help prevent these complications. Some studies show some benefit, while others show none.

Why do Black women tend to have a less healthy vaginal microbiome? No one is sure yet. It may have to do with personal habits – Black women are more likely to douche than White women8. But are Black women douching because they have more vaginal dysbiosis? It might be a chicken-and-egg scenario. There is also some recent evidence to suggest that vaginal microbiomes are heritable9. And several studies from sub-Saharan Africa show rates of dysbiosis similar to those seen in US Black women10–13. Have American Black women inherited this unhealthy vaginal microbiome generation after generation? Many questions remain, and few answers exist as to the root cause of higher rates of vaginal dysbiosis in Black women.

But it seems that biological reasons for maternal sepsis may actually be less important than behavioral and sociological ones. A study of maternal outcomes from health records in 9 states showed that “patient-related factors” such as chronic disease represented only 34.1% of the cause of maternal mortality due to infection, while “provider-related factors” such as delayed or missed diagnosis leading to ineffective treatment were responsible for 40.9%, and “system-related factors” such as communication and personnel were responsible for another 22.7%14. While these data were not disaggregated by race, due to the overall numbers it is likely that healthcare providers and administrators can do more to close the gap for Black women than patients themselves can by altering personal hygiene habits to improve the vaginal microbiome. But these are not mutually exclusive – pregnant women and those trying to conceive should be given as much support as possible in developing a healthy vaginal microbiome.

Black women deserve better care before, during, and after delivery, and more research needs to be done to address questions surrounding vaginal health. Closing the gap will take effort from all of us.


Additional Resources and Ways to Support Black Maternal Health Week

Downloadable PDF: Racial/Ethnic Disparities in Pregnancy-Related Deaths

BMHW 2023 National Call - YouTube

Black Mamas Matter Alliance - Press Release

Black Maternal Health Week Social Media Kit (BMMA)





1. Centers for Disease Control and Prevention. Infographic: Racial/Ethnic Disparities in Pregnancy-Related Deaths — United States, 2007–2016. Published online 2022. Accessed February 22, 2023. https://www.cdc.gov/reproductivehealth/maternal-mortality/disparities-pregnancy-related-deaths/infographic.html

2. Hoyert D. Maternal Mortality Rates in the United States, 2021. National Center for Health Statistics (U.S.); 2023. doi:10.15620/cdc:124678

3. Declerq E, Zephyrin L. Maternal Mortality in the United States: A Primer. The Commonwealth Fund; 2020. Accessed February 22, 2023. https://www.commonwealthfund.org/publications/issue-brief-report/2020/dec/maternal-mortality-united-states-primer#:~:text=During%20pregnancy%2C%20hemorrhage%20and%20cardiovascular,infection%20is%20the%20leading%20cause

4. Shields A, de Assis V, Halscott T. Top 10 Pearls for the Recognition, Evaluation, and Management of Maternal Sepsis. Obstet Gynecol. 2021;138(2):289-304. doi:10.1097/AOG.0000000000004471

5. Ravel J, Gajer P, Abdo Z, et al. Vaginal microbiome of reproductive-age women. Proc Natl Acad Sci. 2011;108(Supplement_1):4680-4687. doi:10.1073/pnas.1002611107

6. Bennett PR, Brown RG, MacIntyre DA. Vaginal Microbiome in Preterm Rupture of Membranes. Obstet Gynecol Clin North Am. 2020;47(4):503-521. doi:10.1016/j.ogc.2020.08.001

7. Urushiyama D, Ohnishi E, Suda W, et al. Vaginal microbiome as a tool for prediction of chorioamnionitis in preterm labor: a pilot study. Sci Rep. 2021;11(1):18971. doi:10.1038/s41598-021-98587-4

8. Chandra A, Martinez G, Mosher W, Abma J, Jones J. Fertility, Family Planning, and Reproductive Health among U.S. Women: Data from the 2002 National Survey of Family Growth. National Center for Health Statistics. Vital Health Stat 23(25); 2005. Accessed February 22, 2023. https://www.cdc.gov/nchs/data/series/sr_23/sr23_025.pdf

9. Wright ML, Fettweis JM, Eaves LJ, et al. Vaginal microbiome Lactobacillus crispatus is heritable among European American women. Commun Biol. 2021;4(1):872. doi:10.1038/s42003-021-02394-6

10. Happel AU, Balle C, Maust BS, et al. Presence and Persistence of Putative Lytic and Temperate Bacteriophages in Vaginal Metagenomes from South African Adolescents. Viruses. 2021;13(12):2341. doi:10.3390/v13122341

11. Lennard K, Dabee S, Barnabas SL, et al. Microbial Composition Predicts Genital Tract Inflammation and Persistent Bacterial Vaginosis in South African Adolescent Females. Infect Immun. 2018;86(1):e00410-17. doi:10.1128/IAI.00410-17

12. Taha TE, Hoover DR, Dallabetta GA, et al. Bacterial vaginosis and disturbances of vaginal flora: association with increased acquisition of HIV. AIDS Lond Engl. 1998;12(13):1699-1706. doi:10.1097/00002030-199813000-00019

13. Martin HL, Nyange PM, Richardson BA, et al. Hormonal contraception, sexually transmitted diseases, and risk of heterosexual transmission of human immunodeficiency virus type 1. J Infect Dis. 1998;178(4):1053-1059. doi:10.1086/515654

14. Building US Capacity to Review and Prevent Maternal Deaths. Report from Nine Maternal Mortality Committees.; 2018. Accessed February 22, 2023. http://reviewtoaction.org/Report_from_Nine_MMRCs

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