Stages of Labor
What Happens During Labor
During labor, the opening of the uterus (cervix) opens (dilates) as a result of rhythmic tightening and relaxation of the uterine muscles (contractions). Progress in cervical dilation is measured through vaginal examinations from no dilation (a closed cervix or zero centimeters) to complete, or full, dilation (10 centimeters).
Contractions also shorten or thin out the cervix. This is called effacement. Effacement is described in percents. Normally a cervix is two centimeters long. When there is 0 percent effacement there is no shortening or thinning of the cervix. The cervix is thick. When the cervix is 100 percent effaced, it is completely thinned out and feels paper-thin. As labor progresses, regular, strong contractions help the baby descend through the birth canal. The position (station) of the baby's head is determined by the relationship of the head to bony projections in the pelvis (ischial spines). The station of the baby's head is measured in the number of centimeters it is above or below these ischial spines. When the baby's head is two centimeters above the ischial spines it is at a -2 station. When the head is level with the ischial spines it is at 0 station. When it is two centimeters below the ischial spines, the head is at a +2 station. The head is at a +4 to +5 station at birth.
The First Stage of Labor
The first stage of labor begins with the onset of regular uterine contractions that dilate (open) the cervix. It is completed when the cervix is completely or fully dilated at 10 centimeters (about four inches).
Early Labor (Latent Phase of Labor)
During the latent phase of labor, contractions are usually irregular (occurring every five to 20 minutes) and mild to moderately uncomfortable. The contractions may feel like gas pains, bad menstrual cramps, or back discomfort. Bloody show may appear during this time and the bag of water may break. This latent phase of labor may last several hours with a first pregnancy, as long as 20 hours. During this latent phase of labor, the cervix typically dilates to four centimeters. While at home in the latent phase of labor you should alternate between walking and resting. It is important to keep yourself well hydrated and nourished by drinking plenty of fluids and eating lightly. Spending time in a bathtub or shower during this phase may help relieve some discomfort. Also, using slow, deep breathing during the contractions may help you relax. If you are evaluated in the Labor and Delivery Unit and determined to be in the latent phase of labor you will be encouraged to go home until your labor is more active. If you are sent home in early labor you may be given a medication (Serax) to help you rest while you are at home.
At the Beth Israel Deaconess, the physicians, nurse midwives, and nurses in the Labor and Delivery Unit believe the best time to come to the hospital is when you are entering the active phase of labor.
Admission to Labor and Delivery during the latent phase of labor may increase your likelihood of having early interventions.
Active Phase of Labor
The active phase of labor usually begins when the cervix is four or five centimeters dilated. The contractions are more regular (every three to five minutes), of longer duration (45 to 90 seconds), and are stronger. Progress during this phase is more rapid. Controlled breathing is used to help cope with the contractions. Finding a comfortable position becomes more difficult during this phase of labor, as does remaining focused on breathing and relaxation techniques. Pain relief options may be provided during this phase of labor.
The final part of the active phase of labor (transition) is from eight to 10 centimeters, or full dilation. This may be the shortest phase of labor for many women, but it may also be the most intense. Strong contractions occur every two to three minutes and last for 60 to 90 seconds. Rectal pressure, along with an urge to push (bear down), may increase at this time. Your provider will help you determine when to bear down actively with these sensations. During this last stage of labor, it may be too late to receive an injection of analgesics because it could make your baby sleepy at birth. However, epidural anesthesia, which does not pass into your baby's system, may be used during this period.
Throughout the active phase of labor, including transition, your progress will be checked every two hours, unless it is necessary to check more often. If at any time the progress of your labor slows down or stops, your provider will discuss with you and your partner options to help with continued progress. These options include breaking your bag of water (amniotomy) or giving you the medication Pitocin to both strengthen your contractions and increase their frequency.
Normally, women will be admitted to the Beth Israel Deaconess Labor and Delivery Unit during the active phase of labor. After an initial evaluation by the Triage Nurse, you will be admitted to a Labor and Delivery Room. Your primary nurse will perform initial and on going assessments of your health status and your baby's.
Information about the health of your unborn baby is obtained by asking you about the baby's movement and by using an electronic fetal monitor to record the baby's heart rate. An initial 20-to-30-minute reading (strip) of your baby's heart rate will be obtained. For women with an uncomplicated pregnancy and a reassuring fetal monitor strip, the fetal heart rate will be monitored periodically throughout labor and delivery.
The Second Stage of Labor
The second stage of labor begins with complete or full dilation of the cervix (10 centimeters). The second stage of labor may take from 15 to 30 minutes to several hours. Your primary nurse will help you with breathing and pushing techniques. You will be encouraged to push with your contractions, holding your breath as you do so. Some women prefer other methods of pushing your primary nurse will help with whatever technique you prefer. Sensations experienced during the second stage of labor are different, making the need for analgesics unlikely. Without anesthesia, most women have a strong urge to push, which is felt as rectal pressure. Those with epidural anesthesia are usually able to push with the sensation of pelvic pressure.
Many positions are acceptable for pushing. Changing positions when pushing for a long time may be helpful. During this second stage of labor, your progress will be evaluated by your provider at least every hour.
As with the first stage of labor, if the progress of pushing slows down or stops, your provider will discuss with you options to help with continued progress. These may include strengthening your contractions through the use of Pitocin. Occasionally, it is necessary to help in the delivery of your baby's head by using a vacuum extractor or forceps. These instruments may be required because there are signs your baby is being stressed, you are too exhausted to continue pushing your baby out, or your baby needs to be delivered quickly.
As your baby's head is about to be delivered (crowning), your provider will decide if you need an episiotomy. An episiotomy is an incision in the perineal area (between the vaginal opening and the rectum) that enlarges the opening of the birth canal to help with the delivery of your baby's head. Oftentimes a provider may successfully deliver your baby without an episiotomy. Sometimes your perineal tissue may tear (lacerate) with or without an episiotomy.
The Third Stage of Labor
The third stage of labor is the delivery of the placenta (afterbirth). The uterus continues to contract after the delivery of your baby, leading to the separation of the afterbirth from the uterus. This separation usually occurs within five to 15 minutes after the delivery. You may be asked to push to help deliver the placenta. Your provider may massage your uterus through your abdomen to help the uterus contract and to slow down any bleeding.
The Fourth Stage of Labor
The fourth stage of labor is the first hour or two after you deliver. During this time, your provider may have to repair an incision (episiotomy) or tears (lacerations) made during the delivery. This repair is made by giving you stitches with thread that absorbs on its own. You will not have to have these stitches removed later. If necessary, you will receive local anesthesia (numbing medication) called Novocain for these stitches. During the fourth stage, your primary nurse will monitor your blood pressure, pulse, and temperature. She or he will also check to see how well contracted the top of your uterus (fundus) is and the amount of bleeding (lochia) you are having from your vagina. Most often, right after delivery, your baby will be placed on your abdomen. Your primary nurse will dry and wrap the baby in a blanket for warmth. Your nurse will also suction any secretions from your baby's mouth. Your nurse will weigh your baby, check the vital signs (temperature, heart rate, and breathing), and perform an initial examination. Your primary nurse will also help you to initiate breast-feeding, if that is your intention. Within about two hours after delivery, your baby will be transferred to the newborn nursery, and you will be transferred to a postpartum (after childbirth) room, where you will spend the remainder of your hospital stay. Once your baby's examination in the nursery is complete and he or she maintains a stable temperature, we encourage you to have your baby with you in your room.