What are the stages of labor?

Labor happens in three stages and can actually begin weeks before you give birth:

The first stage starts once contractions begin and continues until you’re fully dilated, which means being dilated 10 centimeters, or 4 inches. This means your cervix has opened completely in preparation for childbirth. The second stage is the active stage, during which you begin to push downward. It starts with complete dilation of the cervix and ends with the birth of your baby. The third stage is also known as the placental stage. This stage begins with the birth of your baby and ends with the completed delivery of the placenta.

Most pregnant women go through theses stages without experiencing any problems. Some women, however, may experience abnormal labor during one of the three stages of labor.

What is abnormal labor?

Abnormal labor may be referred to as dysfunctional labor, which simply means difficult labor or childbirth. When labor slows down, it’s called protraction of labor. When labor stops altogether, it’s called arrest of labor.

A few examples of abnormal labor patterns may help you understand how the condition is diagnosed:

An example of an “arrest of dilation” is when the cervix is 6 centimeters dilated during the first and second examinations, which your doctor performs one to two hours apart. This means that the cervix hasn’t dilated at all over the course of two hours, indicating labor has stopped.

In an “arrest of descent”, the head of the fetus is in the same place in the birth canal during the first and second examinations, which your doctor performs one hour apart. This signifies that the baby hasn’t moved farther down the birth canal within the last hour. Arrest of descent is a diagnosis made in the second stage, after the cervix is completely dilated.

To determine whether abnormal labor can be corrected to allow for vaginal delivery, your doctor may decide to promote labor by administering oxytocin (Pitocin). This is a type of medication that stimulates uterine contractions to enhance labor. Your can doctor give you oxytocin through a vein using a medication pump to initiate and maintain regular contractions of the uterus. These contractions help push your baby out of the uterus and help dilate your cervix. The dose necessary to cause sufficient contractions varies considerably from one woman to another.

Types of Abnormal Labor

The following types of abnormal labor may occur at any point during the three stages of labor:

Uterine hypocontractility

Labor may start out well but stop or stall later if the uterus fails to contract sufficiently. This type of abnormal labor is usually referred to as uterine inertia or uterine hypocontractility. Medications that lessen the intensity or frequency of the contractions can sometimes cause it. Uterine hypocontractility is most common in women going through labor for the first time. Doctors usually treat the condition with oxytocin to augment labor. However, your doctor will carefully monitor this condition before giving you oxytocin.

Cephalopelvic disproportion

If labor is still slow or stalled after your doctor gives you oxytocin, your baby’s head may be too large to fit through your pelvis. This condition is commonly called cephalopelvic disproportion (CPD).

Unlike uterine hypocontractility, your doctor can’t correct CPD with oxytocin, so labor can’t progress normally after treatment. As a result, women who experience CPD give birth by cesarean delivery. Cesarean delivery happens through an incision in the abdominal wall and uterus rather than through the vagina. CPD is very rare. According to the American Pregnancy Association, CPD only occurs in approximately one of every 250 pregnancies.

Macrosomia

Macrosomia occurs when a newborn is much larger than average. A newborn is diagnosed with macrosomia if they weigh more than 8 pounds, 13 ounces, regardless of when they’re born. Approximately 9 percent of babies born worldwide have macrosomia.

This condition can cause problems during childbirth that can sometimes result in injury. It also puts the baby at an increased risk for health problems after birth. There are more risks to the mother and baby when a baby’s birth weight is greater than 9 pounds, 15 ounces.

Precipitous labor

On average, the three stages of labor last about six to 18 hours. With precipitous labor, these stages progress much more quickly, lasting only three to five hours. Precipitous labor, also called rapid labor, may occur for several reasons:

  • Your uterus is contracting very strongly, helping to push the baby out more rapidly.
  • Your birth canal is compliant, making it easier for the baby to leave the womb.
  • You have a history of precipitous labor.
  • Your baby is smaller than average.

Precipitous labor presents several risks for the mother. These include vaginal or cervical tearing, heavy bleeding, and shock following birth. Precipitous labor may also make your baby more susceptible to infection if they’re born in an unsterile environment, such as a car or bathroom.

Shoulder dystocia

Shoulder dystocia occurs when the baby’s head is delivered through the mother’s vagina, but their shoulders get stuck inside the mother’s body. This usually isn’t discovered until labor has begun, so there’s no way to predict or prevent it.

Shoulder dystocia can pose some risks for both you and your baby. You may develop certain injuries, including excessive bleeding and tearing of the vagina, cervix, or rectum. Your baby might experience nerve damage and a lack of oxygen to the brain. In most cases, however, babies are delivered safely. Doctors are usually able to ease the baby out by applying pressure to the mother’s lower belly or by turning the baby’s shoulder.

Uterine rupture

A uterine rupture is a tear in the wall of the uterus, usually at the site of a previous incision. This condition is rare, but it’s most often seen in women who’ve had uterine surgery or who have previously given birth by cesarean delivery.

When a uterine rupture occurs, an emergency cesarean delivery is necessary to prevent serious problems for you and your child. Potential problems include brain damage in the baby and heavy bleeding in the mother. In some cases, removal of the uterus, or a hysterectomy, is necessary to stop the mother’s bleeding. However, doctors can repair most uterine tears without any issues. Women with certain types of uterine scars should give birth via cesarean delivery rather than vaginally to avoid uterine rupture.

Umbilical cord prolapse

Umbilical cord prolapse occurs when the umbilical cord slips out of the cervix and into the vagina ahead of the baby. This most often happens during labor, particularly as a result of the premature rupture of membranes. Umbilical cord prolapse can lead to umbilical cord compression, or increased pressure on the umbilical cord.

While in the womb, babies occasionally experience mild, short-term umbilical cord compressions, which are harmless. In some cases, however, these compressions can become more severe and last for longer periods. Such compressions can result in a decreased flow of oxygen to your baby, lowering their heart rate and blood pressure. These problems may lead to serious complications for your baby, including brain damage and delayed development. To help prevent these problems, doctors usually move the baby away from the umbilical cord or deliver the baby immediately by cesarean delivery.

Retained placenta

The placenta is the organ that forms in the uterus and attaches to the uterine wall during pregnancy. It provides your baby with nutrients and removes wastes created by your baby’s blood. After the baby is delivered, the mother normally delivers her placenta through her vagina. However, if the placenta remains in the womb for more than 30 minutes after childbirth, it’s considered a retained placenta.

Retained placenta can occur when your placenta becomes caught behind your cervix or when your placenta remains attached to the uterine wall. If it’s left untreated, retained placenta can cause complications, including a severe infection or blood loss. Your doctor may attempt to remove the placenta by hand to prevent these problems. They might also give you medications to increase contractions so the placenta comes out.

Postpartum hemorrhage

Postpartum hemorrhage occurs when there’s excessive bleeding following childbirth, usually after delivery of the placenta. While a woman will usually lose about 500 milliliters of blood after childbirth, a postpartum hemorrhage will cause a woman to lose nearly double that amount. The condition is most likely to occur after birth by cesarean delivery. It may happen if an organ is cut or if your doctor doesn’t stitch the blood vessels properly.

Postpartum hemorrhage can be very dangerous for the mother. Too much blood loss can cause a steep drop in blood pressure, leading to severe shock if left untreated. In most cases, doctors give blood transfusions to women experiencing postpartum hemorrhage to replace lost blood.

The bottom line

Childbirth is a very complex process. It’s possible for complications to occur. Abnormal labor may affect some women, but it’s fairly rare. Talk to your doctor if you have any questions or concerns about your risk for abnormal labor.