“Labor” and “delivery” describe the process of childbirth. Contractions of the uterus and changes in the cervix (the opening of the uterus) prepare a woman’s body to give birth. Then the baby is born, and the placenta follows.
For most women, labor begins sometime between week 37 and week 42 of pregnancy. Labor that occurs before 37 weeks of pregnancy is considered premature, or preterm.1
Just as pregnancy is different for every woman, the start of labor, the signs of labor, and the length of time it takes to go through labor vary from woman to woman and even from pregnancy to pregnancy.
What is induction of labor?
Induction of labor refers to the use of medications or other methods to induce, or cause, labor. This practice is used to make contractions start so that delivery can occur.1
Induction is usually used only when a problem with the pregnancy risks the health of either the mother or the fetus or when the due date has passed.2
Several weeks before labor begins, the cervix begins to soften (called “ripening”), thin out, and open to prepare for delivery. If the cervix is not ready, especially if labor has not started 2 weeks or more after the due date, a health care provider may recommend medication or other means to ripen the cervix before inducing labor.
Health care providers use a scoring system, called the Bishop score, to determine how ready the cervix is for labor. The scores range from 0 to 13. A score of less than 6 means that the cervix may need help to prepare for labor.1
If the cervix is not ready for labor, a health care provider may suggest one of the following steps to ripen the cervix:1,2
- Stripping the membranes. The health care provider can separate the thin tissue of the amniotic sac, which contains the fetus, from the wall of the uterus. This process causes the body to release prostaglandins (pronounced pros-tuh-GLAN-dins), which soften the cervix and cause contractions.
- Giving prostaglandins. This drug may be inserted into the vagina or given by mouth. The body naturally makes these chemicals to ripen the cervix, but sometimes additional amounts are needed to help labor occur.
- Inserting a catheter. A small tube with an inflatable balloon on the end can be placed in the cervix to widen it.
Once the cervix is ripe, a health care provider may recommend one of the following techniques to start contractions or to make them stronger:1
- Amniotomy (pronounced am-nee-OT-uh-mee). A health care provider uses a tool to make a small hole in the amniotic sac, causing it to rupture (or the water to break) and contractions to start.
- Giving oxytocin (also called Pitocin). Oxytocin is a hormone the body naturally makes that causes contractions. It is given to start labor or to speed up labor that has already begun.
In most cases, induction is limited to situations in which there is a problem with the pregnancy or in which the pregnancy has continued past the infant’s due date. It is usually best to “let the baby set the delivery date” and allow labor to begin on its own, unless there is a medical reason to do otherwise.
Women who want labor induction for non-medical reasons should discuss it with their health care providers.2,3
What are the stages of labor?
A text alternative is available at http://www.nichd.nih.gov/news/resources/links/Pages/text_alt_stages_labor.aspx.
Video en espanol: Las 3 etapas del trabajo de parto
The first stage of labor happens in two phases: early labor and active labor. Typically, it is the longest stage of the process.
During early labor:
- The opening of the uterus, called the cervix, starts to thin and open wider, or dilate.
- Contractions get stronger, last 30 to 60 seconds, and come every 5 to 20 minutes.
- The woman may have a clear or slightly bloody discharge, called “show.”
A woman may experience this phase for up to 20 hours, especially if she is giving birth for the first time.
During active labor:
- Contractions become stronger, longer, and more painful.
- Contractions come closer together, meaning that the woman may not have much time to relax in between.
- The woman may feel pressure in her lower back.
- The cervix starts dilating faster.
- The fetus starts to move into the birth canal.
At this stage, the cervix reaches full dilation, meaning that it is as open as it needs to be for delivery (10 centimeters). The woman begins to push (or is sometimes told to “bear down”) to help the baby move through the birth canal.
During stage 2:
- The woman may feel pressure on her rectum as the baby’s head moves through the vagina.
- She may feel the urge to push, as if having a bowel movement.
- The baby’s head starts to show in the vaginal opening (called “crowning”).
- The health care provider guides the baby out of the vagina.
This stage can last between 20 minutes and several hours. It usually lasts longer for first-time mothers and for those who receive certain pain medications.
Once the baby comes out, the health care provider cuts the umbilical cord, which connected the mother and fetus during pregnancy. In stage 3, the placenta is delivered. The placenta is the organ that gave the fetus food and oxygen through the umbilical cord during the pregnancy. It separates from the wall of the uterus and also comes out the birth canal. The placenta may come out on its own, or its delivery may require a provider’s help.
During stage 3:
- Contractions begin 5 to 10 minutes after the baby is delivered.
- The woman may have chills or feel shaky.
Typically, it takes less than 30 minutes for the placenta to exit the vagina. The health care provider may ask the woman to push. The provider might pull gently on the umbilical cord and massage the uterus to help the placenta come out. In some cases, the woman might receive medication to prevent bleeding.1,2,3,4,5,6,7
What are the options for pain relief during labor and delivery?
The amount of pain felt during labor and delivery is different for every woman. The level of pain depends on many factors, including the size and position of the baby, the woman’s level of comfort with the process, and the strength of her contractions.
There are two general ways to relieve pain during labor and delivery: using medications and using “natural” methods (no medications). Some women choose one way or another, while other women rely on a combination of the two.
A woman should discuss the many aspects of labor with her health care provider well before labor begins to ensure that she understands all of the options, risks, and benefits of pain relief during labor and delivery before making a decision. It might also be helpful to put all the decisions in writing to clarify things for all those who might be involved with delivering the baby.
Pain-relief drugs fall into two categories: analgesics (pronounced an-uhl-JEE-ziks) and anesthetics (pronounced an-uhs-THET-iks).1
Each category has different forms of medications. Some of these medications carry risks. It is important for women to discuss medications with their health care provider before going into labor to ensure that they are making informed decisions about pain relief.
Analgesics
Analgesics relieve pain without causing total loss of feeling or muscle movement. These drugs do not always stop pain completely, but they reduce it.
- Systemic analgesics affect the whole nervous system rather than a single area. They ease pain but do not cause the patient to go to sleep. Systemic analgesics are often used in early labor. They are not given right before delivery, because they may slow the baby’s breathing and reflexes. They are given in three ways:
- Injected into a muscle or vein
- Administered through a small tube placed in a vein. The woman can often control the amount of analgesic flowing through the tube.
- Inhaled or breathed in with a mixture of oxygen.2 The woman holds a mask to her face, so she decides how much or how little analgesic she receives for pain relief.
- Regional analgesics relieve pain in one region of the body. In the United States, regional analgesia is the most common way to relieve pain during labor.3 Several types of regional analgesia can be given during labor:
- Epidural analgesia, also called an epidural block or an epidural, causes loss of feeling in the lower body while the patient stays awake. The drug starts working about 10 minutes to 20 minutes after it is given. A health care provider injects the drug near the spinal cord. A small tube (catheter) is placed through the needle. The needle is then withdrawn, but the tube stays in place. Small amounts of the drug can then be given through the catheter throughout labor without the need for another injection.
- A spinal block is an injection of a much smaller amount of the drug into the sac of spinal fluid around the spine. The drug starts working right away, but it lasts for only 1 to 2 hours. Usually, a spinal block is given only once during labor, to help with pain during delivery.
- A combined spinal-epidural block, also called a “walking epidural,” gives the benefits of an epidural block and a spinal block. The spinal part relieves pain immediately. The epidural part allows drugs to be given throughout labor. Some women may be able to walk around after a combined spinal-epidural block.
Anesthetics
Anesthetics block all feeling, including pain.
- General anesthesia causes the patient to go to sleep. The patient does not feel pain while asleep.
- Local anesthesia removes all feeling, including pain, from a small part of the body while the patient stays awake. It does not lessen the pain of contractions. Health care providers often use it when performing an episiotomy (pronounced uh-pee-zee-OT-uh-mee), a surgical cut made in the region between the vagina and anus to widen the vaginal opening for delivery or when repairing vaginal tears that happen during birth.
Women who choose natural childbirth rely on a number of ways to ease pain without taking medication. These include:4,5,6
- The company of others who offer reassurance, advice, or other help throughout labor, also known as continuous labor support7,8
- Relaxation techniques, such as deep breathing, music therapy, or biofeedback
- A soothing atmosphere
- Moving and changing positions frequently
- Using a birthing ball
- Massage
- Yoga
- Taking a bath or shower
- Hypnosis
- Using soothing scents (aromatherapy)
- Acupuncture or acupressure
- Applying small doses of electrical stimulation to nerve fibers to activate the body’s own pain-relieving substances (called transcutaneous electrical nerve stimulation, or TENS)
- Injecting sterile water into the lower back, which can relieve the intense discomfort and pain in the lower back known as back labor
What is a C-section?
A cesarean delivery, also called a C-section or cesarean birth, is the surgical delivery of a baby through a surgical cut or incision in a woman’s abdomen and uterus. After the baby is removed from the womb, the uterus and abdomen are closed with stitches that later dissolve.1
According to the U.S. Centers for Disease Control and Prevention, in 2015, 32% of births were by cesarean delivery—the lowest rate since 2007. Between 1996 and 2008, the number of cesarean deliveries increased by 72%.2
Cesarean delivery may be necessary in the following circumstances:1,3
- Labor is not progressing. Contractions may not open the cervix enough for the baby to move into the vagina for delivery.
- The infant’s health is in danger. The umbilical cord, which connects the fetus to the uterus, may become pinched, or the fetus may have an abnormal heart rate. In these cases, a cesarean delivery allows the baby to be delivered quickly to address and resolve the baby’s health problems.
- The baby is in the wrong position. Most often when this occurs, the baby is breech, or in a breech presentation, meaning that the baby is coming out feet first instead of head first. The baby may also be in a transverse (sideways) or oblique (diagonal) position.
- The pregnant woman is delivering two or more fetuses (multiple pregnancy). A cesarean delivery may be needed if labor has started too early (preterm labor), if the fetuses are not in good positions within the uterus for natural delivery, or if there are other problems.
- The baby is too large. Larger infants are at risk for complications during delivery. These include shoulder dystocia (pronounced dis-TO-she-ah), when the infant’s head is delivered through the vagina but the shoulders are stuck.4 Women with gestational diabetes, especially if their blood sugar levels are not well controlled, are at increased risk for having large babies.
- The placenta has problems. Sometimes the placenta is not formed or working correctly, is in the wrong place in the uterus, or is implanted too deeply or firmly in the uterine wall. These issues can cause problems, such as preventing needed oxygen and nutrients from reaching the fetus or causing vaginal bleeding.5
- The mother has an infection, such as HIV or herpes, that could be passed to the baby during vaginal birth. Cesarean delivery could help prevent transmission of the virus to the infant.
- The mother has a specific medical condition. A cesarean delivery enables the health care provider to better manage the mother’s health issues.
Women who have a cesarean delivery may be given pain medication with an epidural block, a spinal block, or general anesthesia. An epidural block numbs the lower part of the body through an injection in the spine. A spinal block also numbs the lower part of the body, but through an injection directly into the spinal fluid. Women who receive general anesthesia, often used for emergency cesarean deliveries, will not be awake during the surgery.1
Cesarean delivery is a type of surgery, so it has risks and possible complications for both mother and baby.
Possible risks from a cesarean delivery include:1
- Infection
- Blood loss
- Blood clots in the legs, pelvic organs, or lungs
- Injury to surrounding structures, such as the bowel or bladder
- Reaction to medication or anesthesia used
It is important to note that these risks also apply, to some degree, to vaginal birth.
A woman who has a cesarean delivery may also have to stay in the hospital longer than a woman who has had a vaginal delivery.
The more cesarean deliveries a woman has, the greater her risk of certain medical problems and problems with future pregnancies, such as uterine rupture and problems with the placenta.6
Some women may want to have a cesarean birth even if vaginal delivery is an option. Women should discuss their options in detail with their health care provider before making a decision about a type of delivery. The decision should consider the impact of the delivery not only on the current pregnancy but also on future pregnancies. The safest method of delivery for both the mother and the fetus is an uncomplicated vaginal delivery.
Regardless of the type of delivery, unless there is a medical necessity, delivery should not occur before 39 weeks of pregnancy (called “full term”). Watch this video to learn why it is important for the mother’s and infant’s health to wait until at least 39 weeks to deliver unless there is a medical reason to do so earlier.
What is vaginal birth after cesarean (VBAC)?
VBAC refers to vaginal delivery of a baby after a previous pregnancy was delivered by cesarean delivery.
In the past, pregnant women who had one cesarean delivery would automatically have another. But research shows that, for many women who had prior cesarean deliveries, attempting to give birth vaginally—called a trial of labor after cesarean delivery (TOLAC)1—and VBAC might be safe options in certain situations.
In fact, NICHD research shows that among appropriate candidates, about 75% of VBAC attempts are successful.2 A 2010 NIH Consensus Development Conference on VBAC evaluated available data and determined that VBAC was a reasonable option for many women.3
NICHD-supported researchers also developed a way to calculate a woman’s chances of a successful VBAC.4 Access the calculator. Please note that this calculator only determines the likelihood of successful VBAC; it does not guarantee success.
Women should discuss VBAC and TOLAC with their health care providers early in pregnancy to learn whether these options are appropriate for them. Providers are encouraged to discuss plans for VBAC or refer women to a facility that can support VBAC when it is medically safe to consider.5
When is VBAC appropriate?
VBAC may be safe and appropriate for some women, including those:6
- Whose prior cesarean incision was across the uterus toward its base (called a low-transverse incision)—the most common type of incision. Note that the incision on the uterus is different than the incision on the skin.
- With two previous low-transverse cesarean incisions
- Who are carrying twins
- With an unknown type of uterine incision
- No abdominal surgery
- A lower risk of hemorrhage and infection compared with a C-section
- Faster recovery
- Potential to avoid the risks of many cesarean deliveries, such as hysterectomy, bowel and bladder injury, blood transfusion, infection, and abnormal placenta conditions
- Greater likelihood of being able to have more children in the future
If labor fails to progress or if there is another problem, a woman may need a C-section after trying TOLAC. Most risks associated with C-section after TOLAC are similar to those associated with choosing a repeat cesarean. They include:1,7
- Uterine rupture
- Maternal hemorrhage and infection
- Blood clots
- Need for a hysterectomy
What are some common complications during labor and delivery?
Each pregnancy and delivery is different, and problems may arise.
If complications occur, providers may assist by monitoring the situation closely and intervening, as necessary.
Some of the more common complications are:1,2
- Labor that does not progress. Sometimes contractions weaken, the cervix does not dilate enough or in a timely manner, or the infant’s descent in the birth canal does not proceed smoothly. If labor is not progressing, a health care provider may give the woman medications to increase contractions and speed up labor, or the woman may need a cesarean delivery.3
- Perineal tears. A woman’s vagina and the surrounding tissues are likely to tear during the delivery process. Sometimes these tears heal on their own. If a tear is more serious or the woman has had an episiotomy (a surgical cut between the vagina and anus), her provider will help repair the tear using stitches.4,5
- Problems with the umbilical cord. The umbilical cord may get caught on an arm or leg as the infant travels through the birth canal. Typically, a provider intervenes if the cord becomes wrapped around the infant’s neck, is compressed, or comes out before the infant.5
- Abnormal heart rate of the baby. Many times, an abnormal heart rate during labor does not mean that there is a problem. A health care provider will likely ask the woman to switch positions to help the infant get more blood flow. In certain instances, such as when test results show a larger problem, delivery might have to happen right away. In this situation, the woman is more likely to need an emergency cesarean delivery, or the health care provider may need to do an episiotomy to widen the vaginal opening for delivery.6
- Water breaking early. Labor usually starts on its own within 24 hours of the woman’s water breaking. If not, and if the pregnancy is at or near term, the provider will likely induce labor. If a pregnant woman’s water breaks before 34 weeks of pregnancy, the woman will be monitored in the hospital. Infection can become a major concern if the woman’s water breaks early and labor does not begin on its own.7,8
- Perinatal asphyxia. This condition occurs when the fetus does not get enough oxygen in the uterus or the infant does not get enough oxygen during labor or delivery or just after birth.3,4
- Shoulder dystocia. In this situation, the infant’s head has come out of the vagina, but one of the shoulders becomes stuck.5
- Excessive bleeding. If delivery results in tears to the uterus, or if the uterus does not contract to deliver the placenta, heavy bleeding can result. Worldwide, such bleeding is a leading cause of maternal death.9 NICHD has supported studies to investigate the use of misoprostol to reduce bleeding, especially in resource-poor settings.
Delivery may also require a provider’s special attention when the pregnancy lasts more than 42 weeks, when the woman had a C-section in a previous pregnancy, or when she is older than a certain age.
References
