Labor, the process by which a baby is delivered, can be both a joyful and painful experience. In Stages of labor process, the mother undergoes huge physiological and emotional stress, from the first contractions of the latent phase through to the delivery of the placenta.
Stages of labor and birth involves strong contractions of the uterine muscle that open up the cervix and expel the baby through the birth canal. Irregular, short-lived “tightenings” known as Braxton-Hicks contractions may be felt much earlier in the pregnancy. As labor progresses, contractions become stronger, last longer, and occur at regular, increasingly short, intervals— most women require analgesics. Contractions and fetal response are monitored by a cardiotocograph
(see right) via sensors on the abdomen and on the baby’s head as it presents through the opening cervix.
The CTG shows two corresponding lines: the strength of uterine contractions and the correlating fetal heart rate. Normal fetal heart rate is 110–160 beats per minute, and abnormal patterns, such as deceleration, indicate fetal distress during contractions.
STAGES OF LABOR:
Labor begins in response to the release of oxytocin hormone, which stimulates uterine contractions. It divides into three stages: the latent stage occurs when the cervix starts to dilate; the first stage is defined by dilation of the cervix from 11 /2 to 4 in (4 to 10 cm); the second stage, from full cervical dilation to delivery of the baby; and the third stage ends with delivery of the placenta.
During the second stage, pushing, or bearing down, by the mother is synchronized with the contractions to help expel the baby. Maternal pain, particularly during the second and third stages, may be managed by oral or injected analgesics or epidural anesthesia.
Common problems include failure to progress, abnormal presentations such as “breech,” tearing of the birth canal and perineum, and difficult placental delivery. Forceps or vacuum suction may be used to help pull out the baby, while cesarean section (delivery through the abdominal wall) is used when either the baby or the mother is at risk.
Stage 1: Dilation of the cervix:
In the first stage of active labor, the cervix dilates from 1½ to 4 in (4 to 10 cm), which can take hours. Delivery can only begin when the cervix is fully dilated. The baby usually faces its mother’s back, so the widest part of its head passes through the widest axis of the pelvis.
Stage 2: Descent through birth canal
The presenting part, usually the head, is pushed forward by repeated contractions and pushing. The head progresses from the open cervix, through the vagina, until visible at the perineum (“crowning”). It begins to flex backward to allow the rest of the body to follow.
RUPTURE OF MEMBRANES:
Shortly before labor is due to begin, the membrane of the amniotic sac that surrounds the fetus ruptures, allowing amniotic fluid to leak out into the birth canal. This is known as the water breaking and most women go into spontaneous labor within 24 hours. If it occurs before 37 weeks, it is considered premature rupture of the membranes, and may put the fetus at risk of infection or premature delivery. Conversely, if the membranes have not ruptured naturally, or if labor is being induced, they may be ruptured artificially to speed up labor and allow a fetal monitor to be attached to the baby’s scalp.
1:The show, As the cervix starts to open, either before or during labor, the mucus plug, which has sealed the cervical canal until now, loosens and is passed out. This is known as the “bloody show.”
Muscular contractions start in the upper part of the uterus (the fundus) causing the cervix to thin, stretch, and dilate,
preparing the way for the fetus.
The amniotic sac stretches and eventually ruptures under the pressure of the contractions, releasing the amniotic fluid and allowing further descent of the fetus’s head.
Stage 3: Delivery of the baby
As the head is delivered, the doctor ensures that the baby’s airway is clear of mucus, and that the umbilical cord is not wrapped around its neck. The baby turns in the birth canal to allow the shoulders to be delivered. The rest of the body then slips out easily.
Stage 4: Delivery of the placenta
Further contractions compress the uterine blood vessels, preventing blood loss. The doctor eases the placenta out by pulling the umbilical cord and applying pressure to the lower abdominal wall, or an injection of oxytocin hormone may be given to induce delivery.