There are several requirements for a vaginal birth
Placenta location
The placenta must be clear of the cervix to have a vaginal birth. When the placenta (placenta previa) or umbilical cord blood vessels (vasa previa) are near the cervix, a Cesarean birth is indicated.
Baby presentation
Normally the baby should be head down. In some circumstances, a baby in breech (bottom down) presentation can also be born vaginally.
Baby status
The baby should be tolerating the labour process well. The fetal heart rate tracing is one way we monitor how the baby is doing during labour.
Cervix fully dilated
The cervix must be fully dilated (10 centimeters) for the baby to be born vaginally.
