Definition of Labor

Labor is a series of continuous, progressive contractions of the uterus that help the cervix dilate and efface (thin out). This lets the fetus move through the birth canal. Labor usually starts two weeks before or after the estimated date of delivery. However, the exact trigger for the onset of labor is unknown.

Signs of Labor

While each woman experiences labor differently, some common signs of labor may include:

• Bloody show. A small amount of mucus, slightly mixed with blood, may be expelled from the vagina.

• Contractions. Uterine muscle spasms that occur at intervals of less than 10 minutes may signify that labor has started. These may become more frequent and severe as labor progresses.

• Rupture of the amniotic sac (bag of water). If you experience amniotic fluid gushing or leaking from your vagina, go to the hospital immediately and contact your health care provider. Most women go into labor within hours of the amniotic sac breaking. If labor does not begin soon after rupturing your amniotic sac, you will be given medications to induce your labor. This step is often taken to prevent infection and other delivery complications.

If you are unsure about the start of your labor, call your health care provider.

Different Stages of Labor

Typically, labor is divided into three stages: 

• First stage. During the onset of labor, your cervix will complete dilation. Early in this stage, you may not recognize that you are in labor if your contractions are mild and irregular. Early labor is divided into two phases:

  • The latent phase is marked by strong contractions that usually occur at five- to 20-minute intervals. During this phase, your cervix will dilate approximately 3 to 4 centimeters and efface. This is usually the longest and least intense phase of labor. You may be admitted to the hospital during this phase. Your doctor will perform pelvic exams to determine the dilation of the cervix.

  • The active phase is signaled by the dilation of the cervix from 4 to 10 centimeters. Your contractions will likely increase in length, severity and frequency, occurring at three- to four-minute intervals. In most cases, the active phase is shorter than the latent phase.

• Second stage. Often referred to as the pushing stage of labor, this stage starts when your cervix is completely opened and ends with the delivery of your baby. During the second stage, you become actively involved by pushing the baby through the birth canal. Crowning occurs when your baby’s head is visible at the opening of the vagina. The second stage is usually shorter than the first stage, and may take between 30 minutes and three hours for your first pregnancy.

• Third stage. After your baby is delivered, you will enter the third and final stage of labor. This stage involves the passage of the placenta (the organ that nourished your baby inside of the uterus) out of the uterus and through the vagina. The delivery of the placenta may take up to 30 minutes.

Since each labor experience is different, the amount of time required for each stage will vary. If labor induction is not required, most women will deliver their baby within 10 hours of being admitted to the hospital. Labor is generally shorter for subsequent pregnancies.

Induction of Labor

In some cases, labor has to be induced or stimulated to begin. The reasons for induction vary. Labor induction is not initiated before 39 weeks of pregnancy unless there is a problem. The most common reasons for induction include the following:

• The mother or fetus is at risk due to complications.

• The pregnancy has continued too far past the due date.

• The mother has pre-eclampsia, eclampsia or chronic high blood pressure.

• The fetus has been diagnosed with poor growth.

Labor may be induced by:

• Inserting vaginal suppositories that contain prostaglandin to stimulate contractions.

• Giving an intravenous (IV) infusion of oxytocin (a hormone produced by the pituitary gland that stimulates contractions) or a similar drug.

• Artificially rupturing the amniotic sac.

Hospital Care During Labor

When you first arrive at the hospital in labor, the nursing staff may perform a physical exam of your abdomen to determine the size and position of the fetus. The nurses may also examine your cervix for dilation and effacement.

To monitor your health, the nursing staff may check the following:

• Blood and urine samples

• Blood pressure

• Frequency and intensity of contractions

• Temperature

• Weight

In addition, your baby’s health is carefully monitored during labor. A monitor may be placed over your abdomen to keep track of the fetal heart rate.

You may receive IV fluids during labor. The IV line, a thin, plastic tube inserted into a vein (usually in your forearm), can also be used to give medicine. IV fluids are usually given once active labor has begun and when you have epidural anesthesia.

Pain Management Options During Labor

You have many options to relieve pain during labor and delivery. In general, you and your health care provider should choose the safest, most effective method of pain relief available. This decision will be determined by your:

• Preference

• Health

• Baby’s health

• Health care provider’s recommendation

The following are the most common natural and medication-based methods for managing the pain associated with labor and delivery:

Nonmedicated Pain Management

As part of natural childbirth, these pain management strategies provide comfort and relieve stress without the use of medication. Many women have successfully learned natural techniques to help them feel more comfortable and in control during labor and birth. These techniques include:

• Relaxation. This technique can improve your ability to detect and release tension. During progressive relaxation, you can learn to relax various muscle groups in series.

• Touch. This may include massage or light stroking to relieve tension. A jetted bath or a shower during labor may also help relieve pain or tension. Ask your health care provider before taking a tub bath during labor.

• Hot or cold therapy. A warm towel or a cold pack may help relax tense or painful areas.

• Imagery. Using the mind to form mental pictures may help create and promote relaxed feelings.

• Meditation or focused thinking. Meditation helps your mind focus on an object or task, such as breathing, instead of discomfort.

• Breathing. These techniques use different patterns and types of breathing to help direct your mind away from discomfort.

• Positioning and movement. Many women find that changing positions and moving around during labor helps to relieve discomfort and may even accelerate the process. Rocking in a rocking chair, sitting in the Tailor sit position, sitting on a special birthing ball, walking or swaying may also help relieve discomfort. Your health care provider can help you find comfortable positions that are safe for you and your baby.

Medicated Pain Management 

Analgesics. Pain relief medications, such as meperidine, may be used during labor in small amounts with very few complications. However, if given in large amounts or in repeated doses, analgesics can slow the activity of the breathing center in the brain of the mother and child.

Anesthesia. This type of medicine is designed to cause a loss of sensation in various areas of the body. Anesthesia medications include:

• Local block. Anesthesia injected in the perineal area (the area between the vagina and rectum) numbs the area for repair of a tear or episiotomy after delivery.

• Pudendal block. Used for vaginal deliveries, this type of local anesthesia is injected into the vaginal area affected by the pudendal nerve. Since it causes complete numbness in the vaginal area without affecting the contractions of the uterus, you can remain active in pushing the baby through the birth canal.

• Epidural anesthesia (epidural block). This type of anesthesia involves infusing numbing medications through a thin catheter that has been inserted into the space that surrounds the spinal cord in the lower back, causing a loss of sensation in the lower body. Infusions of medications may be increased or stopped as needed. This type of anesthesia is used during labor and for vaginal and cesarean deliveries.

  The most common complication of epidural anesthesia is low blood pressure in the mother. Because of this, most women need to have an intravenous infusion of fluids before epidural anesthesia is given. Another risk of epidural anesthesia is a postpartum headache. It may develop if the epidural needle enters the spinal canal rather than staying in the space surrounding the canal. Your anesthesiologist will discuss the risks, benefits and alternatives to this method of pain management.

• Epidural analgesia. This is sometimes called a walking epidural because the medication infused through the epidural is an analgesic. While it does help relieve pain, it does not numb your body or prohibit movement. Combinations of medications may be used in this type of epidural to provide both analgesic and anesthetic effects. This type of epidural may be used to relieve pain during labor and vaginal deliveries.

  Similar to epidural anesthesia, the most common complication of epidural analgesia is low blood pressure in the mother. Another risk of epidural analgesia is a postpartum headache caused by the epidural needle entering the spinal canal.

• Spinal anesthesia. This type of anesthesia involves injecting a single dose of the anesthetic agent directly into your spinal fluid. Spinal anesthesia acts very quickly and causes complete loss of sensation and loss of movement in your lower body. This type of anesthesia is often used for cesarean deliveries.

• Spinal analgesia. This involves injecting an analgesic medication into the spinal fluid to provide pain relief without numbing. Spinal analgesia may be used in combination with epidural anesthesia or analgesia to provide pain relief during labor or after delivery.

• General anesthesia. Often used in emergency cesarean deliveries, this type of pain relief involves administering an anesthetic agent that causes you to go to sleep.