Maternal mortality rates are very low. You are talking about 25 or so per 100,000 births. Which means that if you have a child you have a 0.025% chance of dying and a 99.975% chance of living. This doesn’t mean we shouldn’t pay attention to it, but it is important to keep things in perspective. Most of the people claiming to know the reason or where to cast blame seem to all line up with what they want funding for anyway. If you think Planned Parenthood or Medicaid are underfunded then you are going to cite those things as reasons. It is called confirmation bias.
The real reason is likely increased age of women becoming mothers. This is due to this cultural belief that women should get their careers on the right foot before having kids which is in argument with their bodies ability to have kids and then recover. Having a child takes a toll on the body. Why do athletes stop being able to perform as they get older? Their bodies aren’t able to recover as well. So this cultural belief that women should wait to have kids combines with the availability of fertility treatments that make it easier to get pregnant well into your 40s ends up increasing the maternal mortality rate.