This kind of labor most often occurs on a special bed, when a woman is in the supine position with legs bent and diluted to the side legs.
Advantages:
1. New mother feels less discomfort
2. It's easier to push
3. Reduced pain
4. Reduced duration of the second stage of labor
5. Reduced the number of intracranial injuries in children
Disadvantages:
1. Poorly visible crotch and it is hard to "protect"
2. More deep perineal tears
3. Difficult to monitor the status of the fetus and the epidural
4. To carry out deliveries in the upright position requires special beds