Labor and Delivery

Overview

The terms “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 is considered premature, or preterm.

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.

True Labor vs. False Labor

“False labor” refers to irregular contractions that sometimes happen before true labor begins. These contractions are also called Braxton Hicks contractions. It can be hard to tell the difference between Braxton Hicks contractions and true labor contractions.

The following differences can help distinguish false labor from true labor:

• Timing of contractions: In false labor, contractions do not come regularly and do not get closer together. In true labor, contractions come at regular times, get closer together over time, and each lasts about 30–70 seconds.
• Effect of movement: In false labor, contractions may stop when the woman walks, rests, or changes position. In true labor, contractions continue despite movement.
• Strength of contractions: In false labor, contractions are usually weak and do not get much stronger, or they may start strong and get weaker. In true labor, contractions get steadily stronger.
• Pain of contractions: In false labor, the woman usually feels pain only in the front. In true labor, pain usually starts in the back and moves to the front.

The primary sign of true labor is a series of contractions that arrive regularly, become stronger, last longer, and grow more frequent over time. Women who have regular contractions every five to ten minutes for an hour should let their healthcare provider know.

Signs of Approaching Labor

Several signs may indicate that labor is near:

• Lightening: This term refers to when the fetus “drops,” or moves lower in the uterus. This may happen several weeks or only a few hours before labor begins, and not all fetuses drop before birth. Lightening gets its name from the feeling of lightness or relief that some women experience when the fetus moves from the rib cage to the pelvic area. It allows some women to breathe more easily and more deeply and may provide relief from heartburn.
• Increase in vaginal discharge: Called “show” or “the bloody show,” the discharge can be clear, pink, or slightly bloody. This discharge occurs as the cervix begins to open and can happen several days before labor or just as labor begins.

Other signs of labor include:

• Change in vaginal discharge
• Pain or pressure around the front of the pelvis or the rectum
• Low, dull backache
• Cramps that feel like menstrual cramps, with or without diarrhea
• A gush or trickle of fluid, which is a sign of water breaking

It is important to discuss labor and signs of labor with a healthcare provider early in pregnancy, before labor begins. Some providers may want a woman to wait until she has multiple signs of labor or is in “active” labor before coming to the hospital or birthing center.

Induction of Labor

Induction of labor refers to the use of medicines or other methods to cause labor.

This practice is used to make contractions start so that delivery can occur. 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. Women who want labor induction for non-medical reasons should discuss it with their healthcare providers.

If the cervix is not ready for labor, a healthcare provider may suggest one of the following steps to prepare the cervix, also known as “ripening” the cervix:

• Stripping the membranes: The healthcare provider separates the thin tissue of the amniotic sac from the wall of the uterus, causing the body to release prostaglandins, which soften the cervix and cause contractions.
• Giving prostaglandins: This drug may be inserted into the vagina or given by mouth.
• 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 healthcare provider may recommend one of the following techniques to start or strengthen contractions:

• Amniotomy: A healthcare provider uses a tool to make a small hole in the amniotic sac, causing it to rupture 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.

Timing of Induction

Unless earlier delivery is medically necessary, waiting until at least 39 weeks before delivering gives mother and baby the best chance for healthy outcomes.

During the last few weeks of pregnancy, the fetus’s lungs, brain, and liver are still developing. Research indicates that even babies born at 37 or 38 weeks of pregnancy are at higher risk for poor health outcomes than babies born at 39 weeks of pregnancy or later.

Stages of Labor

Stage 1: Early and Active Labor

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 cervix starts to thin and open wider, or “dilate.”
• Contractions get stronger, last 30-60 seconds, and come every 5-20 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 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 (10 centimeters) meaning it is as open as it needs to be for delivery. The woman begins to push to help the baby move through the birth canal.

Stage 2: Delivery of the Baby

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 healthcare provider guides the baby out of the vagina.

Stage 3: Delivery of the Placenta

Once the baby comes out, the healthcare 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 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 five to ten minutes after the baby is delivered.
• The woman may have chills or feel shaky.

Post-Delivery

The Apgar test, performed one minute and five minutes after birth, gauges an infant’s overall health. A healthcare provider assesses the following aspects of an infant’s health:

• Skin color
• Heart rate
• Reflexes (response to stimulation, such as a mild pinch)
• Muscle tone
• Breathing

Based on this examination, the healthcare provider gives the infant an Apgar score of 1 to 10. The higher the score, the better the infant is doing.

Delivery With Multiples

When women carry multiple fetuses, like twins, triplets, or quadruplets, labor and delivery proceed through the same stages as with a single infant, but with some important differences. For example, women having multiples are more likely to have certain complications. The most common are preterm labor and preterm birth.

In a pregnancy with multiples, providers look to see whether the woman has one or more than one placenta, which direction(s) the fetuses are facing, and where the umbilical cords lie. In addition, they closely monitor the woman’s health, because carrying multiples can increase a woman’s risk of gestational diabetes and preeclampsia. These factors can all affect when and how a provider recommends delivering the babies. Some complications may require a cesarean delivery to resolve.

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 medicines and using “natural” methods. A woman should discuss the many aspects of labor with her healthcare provider well before labor begins to ensure that she understands all the options, risks, and benefits of pain relief during labor and delivery. It might also be helpful to put all the decisions in writing to clarify the options chosen.

Medicines for Pain Relief

Pain-relief drugs fall into two categories: analgesics and anesthetics.

Analgesics relieve pain without causing total loss of feeling or muscle movement:

• 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 and are not given right before delivery, because they may slow the baby’s breathing and reflexes. They can be injected into a muscle or vein, administered through a small tube placed in a vein, or inhaled with a mixture of oxygen.
• 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. Examples include:
  • Epidural analgesia causes loss of feeling in the lower body while the patient stays awake. The drug starts working about 10-20 minutes after it is given. A healthcare provider injects the drug near the spinal cord, and a small tube (catheter) is placed through the needle so that small amounts of the drug can be given throughout labor without the need for another injection.
  • A spinal block is an injection of a smaller amount of the drug into the sac of spinal fluid around the spine. The drug starts working right away but lasts for only one to two hours. Usually, a spinal block is given only once during labor, to help with pain during delivery.

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 from a small part of the body while the patient stays awake. Healthcare providers often use it when performing repairing vaginal tears that happen during birth or when performing an episiotomy, which is a surgical incision that makes the vaginal opening larger.

Natural Methods for Pain Relief

Women who choose natural childbirth rely on a few ways to ease pain without taking medicine. These include:

• Continuous labor support, which is the company of others who offer reassurance, advice, or other help throughout labor
• 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
• Transcutaneous electrical nerve stimulation (TENS), which applies small doses of electrical stimulation to nerve fibers to activate the body’s own pain-relieving substances
• Injecting sterile water into the lower back, which can relieve intense discomfort known as back labor

Lamaze International offers information on many aspects of natural childbirth in its Healthy Birth Practices website.

Complications During Labor and Delivery

Some common complications during labor and delivery include:

• 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 healthcare provider may give the woman medicines to increase contractions and speed up labor, or the woman may need a cesarean delivery.
• 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, her provider will help repair the tear using stitches.
• Problems with the umbilical cord: The umbilical cord may get caught on an arm or leg as the infant travels through the birth canal. A provider typically intervenes if the cord becomes wrapped around the infant’s neck, is compressed, or comes out before the infant.
• Abnormal heart rate of the baby: Many times, an abnormal heart rate during labor does not mean that there is a problem. A healthcare provider will likely ask the woman to switch positions to help the infant get more blood flow. In certain instances, delivery might have to happen right away, and the woman is more likely to need an emergency cesarean delivery.
• 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, she will be monitored in the hospital, and infection can become a major concern.
• 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, delivery, or just after birth.
• Shoulder dystocia: In this situation, the infant’s head has come out of the vagina, but one of the shoulders becomes stuck.
• 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.

Delivery may also require a provider’s special attention when the pregnancy lasts more than 42 weeks, when the woman had a Cesarean delivery in a previous pregnancy, or when she is older than a certain age.

Cesarean Delivery (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.

Circumstances Requiring Cesarean Delivery

Cesarean delivery may be necessary in the following circumstances:

• Labor is not progressing.
• The infant’s health is in danger, such as when the umbilical cord is pinched or the fetus has an abnormal heart rate.
• The baby is in the wrong position, such as breech (feet first), transverse (sideways), or oblique (diagonal).
• The pregnant woman is delivering two or more fetuses.
• The baby is too large, which can lead to complications such as shoulder dystocia.
• The placenta has problems, such as being in the wrong place or implanted too deeply in the uterine wall.
• The mother has an infection, such as HIV or herpes, that could be passed to the baby during vaginal birth.
• The mother has a specific medical condition that requires better management.

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 healthcare provider before making a decision about a type of delivery. For most pregnancies, the safest method of delivery for both the mother and the fetus is an uncomplicated vaginal delivery.

Risks Associated with Cesarean Delivery

Possible risks from a cesarean delivery include:

• Infection
• Blood loss
• Blood clots in the legs, pelvic organs, or lungs
• Injury to surrounding structures, such as the bowel or bladder
• Reaction to medicine or anesthesia used

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.

Vaginal Birth After Cesarean (VBAC)

VBAC refers to vaginal delivery of a baby after a previous pregnancy was delivered by cesarean delivery. 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), and vaginal birth after cesarean might be safe options in certain situations.

Vaginal birth after cesarean may be safe and appropriate for some women, including those:

• Whose prior cesarean incision was across the uterus toward its base (a low-transverse incision)
• With two previous low-transverse cesarean incisions
• Who are carrying twins
• With an unknown type of uterine incision

Benefits of vaginal birth after cesarean include:

• 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

NIH-supported researchers have developed a calculator to help determine a woman’s chances of a successful vaginal birth after cesarean. Women should discuss vaginal birth after cesarean and trial of labor after cesarean delivery with their healthcare providers early in pregnancy to learn whether these options are appropriate for them.

If labor fails to progress or if there is another problem, a woman may need a C-section after trying a trial of labor after cesarean delivery. Most risks associated with C-section after trial of labor after cesarean delivery are similar to those associated with choosing a repeat cesarean and include:

• Uterine rupture
• Maternal hemorrhage and infection
• Blood clots
• Need for a hysterectomy

Preterm Labor

Preterm labor is any labor that occurs from 20 weeks through 36 weeks of pregnancy.

Preterm Labor Symptoms

Labor contractions before 37 weeks of pregnancy are a sign of preterm labor. Women who notice regular, frequent contractions at any point in pregnancy should notify a provider or go to the hospital.

Other symptoms include:

• Change in vaginal discharge, including leaking fluid or bleeding from the vagina
• Feeling of pressure in the pelvis
• Low, dull backache
• Cramps that feel like menstrual cramps
• Abdominal cramps with or without diarrhea

Effects of Preterm Birth

Many organs, including the brain, lungs, and liver, are still developing in the final weeks of pregnancy. The earlier the delivery, the higher the risk of serious disability or death.

Infants born prematurely are at risk for cerebral palsy, developmental delays, and vision and hearing problems. Preterm infants can have problems with breathing and eating and may have to stay in the hospital longer than other infants. Late-preterm infants typically have better health outcomes than those born earlier, but they are still three times more likely to die in the first year of life than are full-term infants. Preterm births can also take a heavy emotional and economic toll on families.

Preterm Labor Diagnosis

If a woman is experiencing signs of labor, the healthcare provider may perform a pelvic exam to see if the membranes have ruptured, the cervix is beginning to get thinner (efface), or the cervix is beginning to dilate. Providers may also do an ultrasound exam and use a monitor to electronically record contractions and the fetal heart rate.

A healthcare provider may also order a fetal fibronectin (fFN) test. This test detects whether the protein fetal fibronectin is being produced. Fetal fibronectin acts like a biological “glue” between the uterine lining and the membrane that surrounds the fetus. If fFN is detected between 24 and 34 weeks of pregnancy, it may be a sign that the woman is at risk of preterm labor and birth. In most cases, the fFN test is performed on women who are showing signs of preterm labor. The fFN test is typically used for its negative predictive value, meaning that if it is negative, it is unlikely that a woman will deliver within the next seven days.

Risk Factors for Preterm Labor

The causes of preterm labor and premature birth are numerous, complex, and only partly understood. Medical, psychosocial, and biological factors may all play a role.

Healthcare providers consider the following factors to put women at high risk for preterm labor or birth:

• A previous preterm labor or birth
• Being pregnant with twins, triplets, or more (called “multiple gestations”), or use of assisted reproductive technology
• Certain anomalies of the reproductive organs, such as a short cervix or a cervix that begins to open early

Certain medical conditions also place a woman at higher risk, including:

• Urinary tract infections
• Sexually transmitted infections
• Certain vaginal infections, such as bacterial vaginosis and trichomoniasis
• High blood pressure
• Bleeding from the vagina
• Certain developmental anomalies in the fetus
• Pregnancy resulting from in vitro fertilization
• Having underweight or obesity before pregnancy
• Short time between pregnancies (less than six months between a birth and the beginning of the next pregnancy)
• Placenta previa, a condition in which the placenta grows in the lowest part of the uterus and covers all or part of the opening to the cervix
• Being at risk for rupture of the uterus (when the wall of the uterus rips open); rupture of the uterus is more likely if you have had a prior cesarean delivery or have had a uterine fibroid removed
• Diabetes and gestational diabetes
• Blood clotting problems

Other factors that may increase risk include:

• Ethnicity: Preterm labor and birth occur more often among certain racial and ethnic groups. For example, infants of African American mothers are more likely to be born preterm than infants of white mothers. American Indian/Alaska Native mothers are also more likely to give birth preterm than are white mothers.
• Age of the mother: Women younger than age 18 are more likely to have a preterm delivery. Women older than age 35 are also at risk because they are more likely to have other conditions — such as high blood pressure and diabetes — that can cause complications requiring preterm delivery.
• Lifestyle and environmental factors, including late or no healthcare during pregnancy, smoking, drinking alcohol, using illegal drugs, domestic violence, lack of social support, stress, long working hours with long periods of standing, and exposure to certain environmental pollutants.

Preterm Labor Treatment and Prevention

Currently, treatment options for preventing preterm labor or birth are somewhat limited, in part because the cause of preterm labor or birth is often unknown.

If a pregnant woman is showing signs of preterm labor, her doctor will often try treatments to stop labor and prolong the pregnancy until the fetus is more fully developed. Treatments include:

• Tocolytics: These drugs can slow or stop contractions of the uterus and may prevent labor for two to seven days. One common treatment is magnesium sulfate, given intravenously.
• Corticosteroids: These medicines can speed up development of the fetus’s lungs and some other organs. Corticosteroids can be particularly effective if the pregnancy is between 24 and 34 weeks and the woman’s healthcare provider suspects that the birth may occur within the next week.
• Cervical cerclage: During this surgical procedure, a doctor stitches the cervix closed. The stitch is then removed closer to the woman’s due date.

Researchers have found that some methods for trying to stop preterm labor are not as effective as once thought, including home uterine monitors and routine screening of all asymptomatic women for bacterial vaginosis. Contrary to expectations, confining the mother to bed rest does not help to prevent preterm birth. In fact, bed rest can make preterm birth even more likely among some women. Women should discuss all their treatment options with their healthcare providers, including the risks and benefits.

Choosing a Birth Setting

Women should talk to their healthcare provider about where they want to deliver their baby. If possible, they should schedule a time to visit the hospital, birthing center, or other setting before making a decision.

The American Academy of Pediatrics (AAP) and the American College of Obstetricians and Gynecologists (ACOG) recommend births in hospitals or birthing centers as the safest options.

Women who are good candidates for home birth:

• Are generally in good health
• Have not had a previous cesarean delivery
• Do not have pregnancy-related health problems or illness
• Do not have multiples
• Have a fetus with good size and health
• Have a fetus in the head-down position
• Go into labor at 37 weeks or later

Planned home births benefit from having the following resources in place:

• A certified nurse-midwife, certified midwife, or practicing physician
• At least one appropriately trained individual whose primary responsibility is the care of the newborn infant
• Quick access to healthcare providers who can provide consultation if complications happen
• A reliable plan for safe and fast transportation to a nearby hospital in case of an emergency

The American College of Obstetricians and Gynecologists notes that allowing women to labor in a birthing pool may have benefits, but it recommends against giving birth in water.

Find Clinical Trials

Clinical trials uncover better ways to prevent, diagnose, treat, and understand diseases and conditions. To ensure results apply to everyone, volunteers of all ages, sexes, and backgrounds, including both healthy individuals and those with specific medical conditions, are needed. Find clinical trials on labor and delivery.

Find Treatment

• The American Association of Birth Centers maintains a list of accredited locations where families can find a birth center near them.
• The American College of Obstetricians and Gynecologists (ACOG) offers resources for women and patients on labor, delivery, and postpartum care.
• The Maternal and Child Health Bureau (MCHB), part of the Health Resources and Services Administration, provides free and confidential access to trained counselors and resources through the National Maternal Mental Health Hotline. Callers can access support and information related to before, during, and after pregnancy 24 hours a day, seven days a week in English, Spanish, and more than 60 other languages.

Community Support

• Association of Women’s Health, Obstetric and Neonatal Nurses (AWHONN) promotes the health of women and newborns, works to strengthen the nursing profession, provides education and resources for health professionals, and offers information for healthy moms and babies.
• March of Dimes supports efforts to help mothers have full-term pregnancies and to study the problems threatening the health of infants.

Note: This resource list is for informational purposes only. It is not comprehensive, and an organization’s inclusion does not constitute an endorsement by NIH.  

Research Information

The National Institutes of Health (NIH) is the largest public funder of biomedical research in the world. NIH invests most of its budget in medical research seeking to enhance life and to reduce illness and disability. NIH-funded research has led to breakthroughs and new treatments helping people live longer, healthier lives, and building the research foundation that drives discovery.

NIH research efforts related to labor and delivery address multiple aspects of the childbirth process, including:

• Basic biology of labor and how labor progresses
• How to determine the appropriate time for a cesarean delivery when labor does not progress
• Basic and clinical studies to improve birth outcomes
• Long-term health outcomes of elective cesarean deliveries and labor inductions
• Prevention and management of preterm labor
• Childbirth practices to prevent mother-to-child transmission of HIV and other infectious diseases
• Efficacy and safety of vaginal birth after cesarean delivery
• Effects of different types of childbirth on maternal health

Several networks supported by the NIH fund or conduct ongoing research in labor and delivery:

• Global Network for Women’s and Children’s Health Research. This network is a partnership committed to improving maternal and infant health outcomes in resource-poor settings. U.S. researchers are paired with investigators in India, Pakistan, Guatemala, Zambia, Kenya, and the Democratic Republic of Congo. The Network’s efforts include tracking pregnancy services and outcomes through a registry that enrolls 60,000 women each year.
• International Maternal, Pediatric, Adolescent AIDS Clinical Trials (IMPAACT) Network. This network focuses on evaluating potential therapies for HIV infection and its related symptoms in infants and pregnant women, including clinical trials of HIV/AIDS interventions for and prevention of mother-to-child transmission.
• Maternal-Fetal Medicine Units (MFMU) Network. Established in 1986, this network focuses on well-designed clinical trials in maternal-fetal medicine and obstetrics, particularly trials that focus on preterm birth. The MFMU Network is studying the effect of inducing labor on the risk of serious illness or infant death, progesterone for preventing preterm twin births, transmission of the hepatitis C virus from mothers to infants, and prevention of congenital cytomegalovirus infection.
• Domestic and International Pediatric and Maternal HIV Clinical Studies Network. This network, supported by NIH’s Maternal and Pediatric Infectious Disease Branch (MPIDB), conducts trials related to preventing and treating HIV infection and its complications in newborns and pregnant women.

In addition, NIH’s Implementing a Maternal health and PRegnancy Outcomes Vision for Everyone (IMPROVE) Initiative supports studies examining preventable causes of maternal deaths and ways to improve health for women before, during, and after pregnancy. It includes a special emphasis on populations that are disproportionately affected.

Find NIH-funded research projects using NIH RePORTER, a searchable database of current and past research projects supported by NIH and other federal agencies.