In a Birth Delivery, the advantages of vertical positions during first-stage labor are the decrease in discomfort, the increase in the speed of labor, and they may decrease the incident of fetal distress.
The disadvantages of the back-lying position during first-stage labor are: the contribution to a long, more difficult labor.
It can cause maternal hypotension by pulling pressure on the inferior vena cava, thereby reducing the oxygen reaching the baby and causing fetal distress.
The advantages of birth in an upright position during second-stage are: The birth canal is slightly shortened as the pelvic outlet is expanded by an average of 28 percent in the squatting, as compared to the supine, position.
Gravity is on the squatting woman's side; squatting can shorten an otherwise long bearing-down stage and is especially helpful if the baby is in a posterior position.
The disadvantages of back-lying or using stirrups during birth are as follows: pushing during birth is more difficult, birth is more difficult, pain is increased, and the risk of perineal lacerations is increased. Additionally, blood flow to the uterus is decreased, resulting from constriction of mother's blood vessels, the risk of having an episiotomy is greater, and the risk of forceps delivery is greater.
