It is really important that this area gets pushed. Women’s health is woefully under funded in research. I spent over a decade research maternal health from a genetic perspective and wanted to add a couple of things that I think contribute to the shocking statistic in the OP.
Some risk factors will be in common across women of African heritage. These include increased risk of gestational diabetes, preeclampsia (about double in black women vs white women), clotting disorders etc. One of the issues we faced in the research I was involved in was that a lot of the genetic research was done in European and American populations so our understanding of the genes at play was all based on a not totally relevant background.
This is also reflected in obstetrics more broadly, working with an African consultant obstetrician she wanted to write a textbook specific to African obstetrics. This obstetrician believed that African women had shorter gestation (38-39 weeks). That due to pelvis physiology the baby’s head didn’t engage till active labour. This is anecdotal (but coming from a consultant obstetrician with 20 years experience in a hospital with 32000 deliveries a year in sub Saharan Africa). My point is the factors may or may not be true but without research specific to pregnancy in other ethnic groups we will always be treating black women based on knowledge based on white women.
Then there are cultural risk factors such as FGM which increases risk of obstruction and haemorrhage. Less engagement with antinatal care etc.
There will be a socioeconomic component, diet, obesity, access and engagement with health care.
There almost certainly is racism component in treatment received such as the example given above of not believing black women with regard to their level of pain.
I guess my point is that it is complex and without research we will never unpick it. It is massively important that this issue is raised. According to the WHO 830 women die a day due to childbirth and associated complications. The more sunlight the better. And the more discussion the less taboo it becomes to acknowledge that there are differences that almost certainly contribute to the horrifying statistic in the OP.
It is also important that this doesn’t become weaponised for the wrong reasons.