I think the assumption they're making with that comment is that this is a result of a higher population of Black women in a specific area of TN, but "more likely to die" isn't necessarily the same as "more deaths," though that may also be true. As the doctor in the article points out, there are factors like discrimination by health care professionals (such as not being believed when they're telling the doctor there is a problem) and complications that occur in higher numbers in Black women (which can be due to other facors stemming from systemic racism such as income, healthcare access, environmental racism, etc).
This is a short article, but there's plenty of papers out there about how people are treated differently by doctors and have different levels of access to healthcare in the US based on what population they belong to (racial, ethnic, lgbtq+, etc) and that women of color typically have the poorest healh outcomes.