Examples of why a flip might not be a good idea include uterine abnormalities in the mother or the cord being wrapped around the baby in a risky way. (romper.com)
Infertility testing examines ovarian function and egg quality, tubal patency (open fallopian tubes), uterine abnormalities inside the uterus, and male factor. (vcrmed.com)
It can also happen if there is a smaller than normal amount of amniotic fluid, a short umbilical cord, or other uterine abnormalities. (doctor-info.website)