“Overall, people who received continuous support were more likely to have spontaneous vaginal births and less likely to have any pain medication, epidurals, negative feelings about childbirth, vacuum or forceps-assisted births, and Cesareans.
In addition, their labors were shorter by about 40 minutes and their babies were less likely to have low Apgar scores at birth. There is a smaller amount of evidence that doula support in labor can lower postpartum depression in mothers.
There is no evidence for negative consequences to continuous labor support.”
https://evidencebasedbirth.com/the-evidence-for-doulas/