Vaginal delivery of a full term baby, or a baby who has reached at least 37 weeks gestation, is the preferred outcome of pregnancies, explains the American Academy of Family Physicians. In uncomplicated pregnancies, normal vaginal deliveries usually require very little intervention.
A spontaneous vaginal delivery is defined as the delivery of a baby through the vagina. In order for a vaginal delivery to occur, the baby must be in a head down position. Dr. Marjorie Greenfield, MD, notes that breech babies, or those who are in the butt first or feet first position, have a higher risk of complications when born vaginally.
Signs and Symptoms of Labor
A vaginal delivery occurs after the mother has gone through labor which dilates her cervix, or the opening to the uterus, to 10cm. Labor also moves the baby into the birth canal. Contractions occur during labor to accomplish these tasks, and are different than the practice contractions, or Braxton Hicks, which are felt throughout pregnancy. Labor contractions are intense, and do not go away with rest. As labor progresses, it becomes more difficult to talk through them. The mucous plug, which is formed to protect the uterus from bacteria, may be passed at the onset of labor. Additionally, a woman’s water may break, with contractions soon to follow.
Stages of Labor
Three stages of labor exist, according to the University of Minnesota, signaling an impending delivery. The first stage of labor occurs as contractions work to thin and dilate the cervix to allow the baby to pass through. The second stage begins when complete dilation to 10cm has occurred, and the body changes gears to deliver the baby. During the second stage, pushing occurs. The mother may be coached to push, or she may be instructed to push when she feels the need. The second stage ends with the birth of the baby. The placenta, the organ which provides nourishment for the baby while in the womb, is delivered during the third stage of labor.
Several factors can influence the ability of a spontaneous vaginal delivery to occur. According to the American Academy of Family Physicians, these include complete placenta previa, herpes virus with active lesions, previous classic uterine incision and untreated HIV infection. Placenta previa occurs when the placenta forms over the cervix. Attempted vaginal delivery could cause severe hemorrhage, and possible maternal and fetal death. A classic uterine incision is a vertical incision, instead of the customary horizontal one. Classic incisions cut through more of the uterine wall, and increases the risk that the uterus could rupture. With active herpes or untreated HIV, both infections are more readily passed to the baby during a vaginal birth.
Length of labor varies between women, and differs if the woman is delivering her first baby. Typically, first labors may last 12 to 24 hours and subsequent labors may last on average, six to eight hours, notes the University of Rochester Medical Center.