Labor and Delivery

"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.

NICHD studies many aspects of labor and delivery: their basic biology, childbirth practices, and management of related problems.

A separate topic covers preterm labor and birth.

About Labor and Delivery

Labor and delivery are the process by which a baby is born, from the body's preparations to when the baby and the placenta leave the womb.

The earliest stage of labor prepares the body for delivery. This is a period of hours or days when the uterus regularly contracts and the cervix gradually thins out (called "effacing") and opens (called "dilation") to allow the baby to pass through.

An illustrated cross-section of a female abdomen carrying a fetus; the fetus has turned and appears ready for delivery. The uterus, placenta, cervix, and vagina are labeled.

Once the cervix has opened completely, the woman can begin pushing to deliver the baby. When the baby and placenta come out through the vagina, it is known as a vaginal delivery.1

Citations

  1. López-Zeno, L. A., & Harrington, L. (2004). Normal labor and delivery. In J. J. Sciarra (Ed.), Gynecology & obstetrics (Volume 2, Chapter 68). Hagerstown, MD: Lippincott Williams & Wilkins. Retrieved August 22, 2017, from http://www.glowm.com/resources/glowm/cd/pages/v2/v2c068.html 

When does labor usually start?

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.

The primary sign of labor is a series of contractions (tightening and relaxing of the uterus) that arrive regularly. Over time, they become stronger, last longer, and are more frequent. Some women may experience false labor, when contractions are weak or irregular or stop when the woman changes positions. Women who have regular contractions every 5 to 10 minutes for an hour should let their health care provider know.

It is important to discuss labor and signs of labor with a health care 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.

Other signs of labor include:2

  • "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. 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 (dilate) and can happen several days before labor or just as labor begins.

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. Providers can check for changes in the cervix to see whether labor has begun. As needed, providers can also give women in preterm labor specialized care. Among women who experience preterm labor, only about 10% go on to give birth within a week.

Other signs of labor include:3

  • 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

Sometimes, if the health of the mother or the fetus is at risk, a woman's health care provider will recommend inducing or causing labor using medically supervised methods, such as medication.4

Unless earlier delivery is medically necessary or occurs on its own, 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.5

The Is It Worth It? Initiative, from NICHD's National Child and Maternal Health Education Program, focuses on raising awareness of the importance of waiting until at least 39 weeks to deliver a baby, unless it is medically necessary to deliver earlier.

Citations

  1. Fleischman, A. R., Oinuma, M., & Clark, S. L. (2010). Rethinking the definition of “term pregnancy.” Obstetrics and Gynecology, 116(1), 136–139.
  2. American College of Obstetricians and Gynecologists. (2011). FAQ: How to tell when labor begins. Retrieved February 13, 2017, from http://www.acog.org/Patients/FAQs/How-to-Tell-When-Labor-Begins
  3. American College of Obstetricians and Gynecologists. (2016). FAQ: Preterm (premature) labor and birth. Retrieved July 17, 2017, from https://www.acog.org/Patients/FAQs/Preterm-Labor-and-Birth
  4. American College of Obstetricians and Gynecologists. (2012). FAQ: Labor induction. Retrieved February 13, 2017, from http://www.acog.org/Patients/FAQs/Labor-Induction
  5. National Child and Maternal Health Education Program. (2013). Moms-to-be: Let baby set the delivery date. Retrieved February 13, 2017, from https://www.nichd.nih.gov/ncmhep/initiatives/is-it-worth-it/Pages/moms.aspx

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

Citations

  1. American College of Obstetricians and Gynecologists. (2012). FAQ: Labor induction. Retrieved February 20, 2017, from https://www.acog.org/Patients/FAQs/Labor-Induction external link
  2. American College of Obstetricians and Gynecologists. (2009). ACOG issues revision of labor induction guidelines. Retrieved February 20, 2017, from http://www.acog.org/About-ACOG/News-Room/News-Releases/2009/ACOG-Issues-Revision-of-Labor-Induction-Guidelines
  3. American College of Nurse-Midwives. (2016). Position statement: Induction of labor. Retrieved February 17, 2017, from http://www.midwife.org/ACNM/files/ACNMLibraryData/UPLOADFILENAME/000000000235/Induction-of-Labor-2016.pdf external link (PDF 270 KB)

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, so you should discuss your options with a health care provider before your due date. Examples include (but are not limited to) the following:
    • 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.

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

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

Citations

  1. American College of Obstetricians and Gynecologists. (2014). FAQ: Medications for pain relief during labor and delivery. Retrieved February 13, 2017, from http://www.acog.org/Patients/FAQs/Medications-for-Pain-Relief-During-Labor-and-Delivery external link
  2. American College of Nurse-Midwives. (2013). Nitrous oxide for pain relief in labor. Retrieved February 13, 2017, from http://www.midwife.org/acnm/files/ccLibraryFiles/Filename/000000003905/
    Nitrous_oxide_for_pain_relief_pregnancy.pdf
    external link(PDF 125 KB)
  3. Schrock, S. D., & Harraway-Smith, C. (2012). Labor analgesia. American Family Physician, 85(5), 447–454. Retrieved February 23, 2017, from http://www.aafp.org/afp/2012/0301/p447.html external link
  4. Leeman, L., Fontaine, P., King, V., Klein, M. C., & Ratcliffe, S. (2003). The nature and management of labor pain: Part I. Nonpharmacologic pain relief. American Family Physician, 68(6), 1109–1113.
  5. Tournaire, M., & Theau-Yonneau, A. (2007). Complementary and alternative approaches to pain relief during labor. Evidence-Based Complementary and Alternative Medicine, 4(4), 409–417.
  6. Makvandi, S., Roudsari, R. L., Sadeghi, R., & Karimi, L. (2015). Effect of birth ball on labor pain relief: A systematic review and meta-analysis. Journal of Obstetrics and Gynecology Research, 41(11), 1679–1686
  7. American College of Obstetricians and Gynecologists. (2017). Approaches to limit intervention during labor and birth. Committee Opinion No. 687. Obstetrics and Gynecology, 129, e20–e28. Retrieved March 20, 2017, from http://www.acog.org/Resources-And-Publications/Committee-Opinions/Committee-on-Obstetric-Practice/Approaches-to-Limit-Intervention-During-Labor-and-Birth external link
  8. Hodnett, E. D., Gates, S., Hofmeyr, G., & Sakala, C. (2013). Continuous support for women during childbirth. Retrieved March 20, 2017, from https://www.cochrane.org/CD003766/PREG_continuous-support-women-during-childbirth external link

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

Citations

  1. Office on Women's Health. (2017). Labor and birth. Retrieved February 21, 2017, from https://www.womenshealth.gov/pregnancy/childbirth-and-beyond/labor-and-birth
  2. López-Zeno, L. A., & Harrington, L. (2004). Normal labor and delivery. In J. J. Sciarra (Ed.), Gynecology & obstetrics (Volume 2, Chapter 68). Hagerstown, MD: Lippincott Williams & Wilkins. Retrieved July 22, 2013, from http://www.glowm.com/resources/glowm/cd/pages/v2/v2c068.html external link
  3. American College of Obstetricians and Gynecologists. (2011). FAQ: How to tell when labor begins. Retrieved February 13, 2017, from http://www.acog.org/Patients/FAQs/How-to-Tell-When-Labor-Begins external link
  4. American College of Nurse-Midwives. (2012). Second stage of labor: Pushing your baby out. Retrieved February 13, 2017, from http://www.midwife.org/ACNM/files/ccLibraryFiles/Filename/000000001793/
    Second%20%20Stage%20of%20Labor%20-%20Pushing%20Your%20Baby%20Out.pdf
    external link (PDF 125 KB)
  5. Joy, S., Lyon, D., & Scott, P. L. (2015). Abnormal labor. Retrieved February 17, 2017, from https://emedicine.medscape.com/article/273053-overview#showall external link
  6. World Health Organization. (2007). Managing complications in pregnancy and childbirth: A guide for midwives and doctors. Retrieved February 21, 2017, from https://apps.who.int/iris/bitstream/handle/10665/43972/9241545879_eng.pdf external link (PDF 5.5 MB)
  7. Maughan, K. L., Heim, S. W., & Galazka, S. S. (2006). Preventing postpartum hemorrhage: Managing the third stage of labor. American Family Physician, 73, 1025–1028. Retrieved April 25, 2017, from http://www.aafp.org/afp/2006/0315/p1025.pdf external link (PDF 172 KB)

What is natural childbirth?

Natural childbirth can refer to many different ways of giving birth without using pain medication, either in the home or at the hospital or birthing center.

Natural Forms of Pain Relief

Women who choose natural childbirth can use a number of natural ways to ease pain. These include1,2:

  • Emotional support
  • Relaxation techniques
  • A soothing atmosphere
  • Moving and changing positions frequently
  • Using a birthing ball
  • Using soothing phrases and mental images
  • Placing a heating pad or ice pack on the back or stomach
  • Massage
  • 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

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. It might also be helpful to put all the decisions in writing to clarify the options chosen.

Citations

  1. March of Dimes. (2010). Natural relief for labor pains. Retrieved December 26, 2013, from http://www.marchofdimes.com/pregnancy/natural-relief-for-labor-pain.aspxExternal Web Site Policy
  2. Tournaire, M., & Theau-Yonneau, A. (2007). Complementary and alternative approaches to pain relief during labor. Evidence-Based Complementary and Alternative Medicine, 4(4), 409–417. Retrieved December 31, 2013, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2176140

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.

Citations

  1. American College of Obstetricians and Gynecologists. (2015). FAQ: Cesarean birth (C-section). Retrieved February 17, 2017, from https://www.acog.org/womens-health/faqs/cesarean-birth external link
  2. Centers for Disease Control and Prevention. (2017). Births: Final data for 2015. National Vital Statistics Reports, 66(1). Retrieved February 20, 2017, from https://www.cdc.gov/nchs/data/nvsr/nvsr66/nvsr66_01.pdf (PDF 1.95 MB)
  3. American College of Obstetricians and Gynecologists. (2014; reaffirmed 2016). Safe prevention of the primary cesarean delivery. Obstetric Care Consensus No. 1. Obstetrics and Gynecology, 123, 693–711. Retrieved February 28, 2017, from http://www.acog.org/Resources-And-Publications/Obstetric-Care-Consensus-Series/Safe-Prevention-of-the-Primary-Cesarean-Delivery external link
  4. Chatfield, J. (2001). ACOG issues guidelines on fetal macrosomia. American Family Physician, 64(1), 169–170.
  5. American College of Obstetricians and Gynecologists. (2016). FAQ: Bleeding during pregnancy. Retrieved February 20, 2017, from http://www.acog.org/Patients/FAQs/Bleeding-During-Pregnancy external link
  6. Spong, C. Y., Berghella, V., Wenstrom, K. D., Mercer, B. M., & Saade, G. R. (2012). Preventing the first cesarean delivery: Summary of a joint Eunice Kennedy Shriver National Institute of Child Health and Human Development, Society for Maternal-Fetal Medicine, and American College of Obstetricians and Gynecologists Workshop. Obstetrics & Gynecology, 120(5), 1181–1193.

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

Benefits of VBAC include:1,6

  • 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

Citations

  1. American College of Obstetricians and Gynecologists. (2011). FAQ: Vaginal birth after cesarean delivery: Deciding on a trial of labor after cesarean delivery. Retrieved February 16, 2017, from https://www.acog.org/Patients/FAQs/Vaginal-Birth-After-Cesarean-Delivery external link
  2. Landon, M. B., Leindecker, S., Spong, C. Y., Hauth, J. C., Bloom, S., Varner, M. W., et al. (2005). The MFMU Cesarean Registry: Factors affecting the success and trial of labor following prior cesarean delivery. American Journal of Obstetrics and Gynecology, 193, 1016–1023.
  3. National Institutes of Health Consensus Development Conference Panel. (2010). National Institutes of Health Consensus Development Conference statement: Vaginal birth after cesarean: New insights March 8–10, 2010. Obstetrics & Gynecology, 115(6), 1279–1295.
  4. Grobman, W. A., Lai, Y., Landon, M. B., Spong, C. Y., Leveno, K. J., Rouse, D. J., et al.; National Institute of Child Health and Human Development (NICHD) Maternal-Fetal Medicine Units Network (MFMU). (2007). Development of a nomogram for prediction of vaginal birth after cesarean delivery. Obstetrics and Gynecology, 109, 806–812
  5. Hauk, L.; American Academy of Family Physicians. Planning for labor and vaginal birth after cesarean delivery: Guidelines from the AAFP. (2015). American Family Physician, 91(3), 197–198. Retrieved February 23, 2017, from http://www.aafp.org/afp/2015/0201/p197.html external link
  6. American College of Obstetricians and Gynecologists. (2010; reaffirmed 2017). ACOG practice bulletin no. 115: Vaginal birth after previous cesarean delivery. Obstetrics and Gynecology, 116(2 Part 1), 450–463. Retrieved August 7, 2017, from https://www.ncbi.nlm.nih.gov/pubmed/20664418
  7. Armstrong, C. (2011). ACOG updates recommendations on vaginal birth after previous cesarean delivery. American Family Physician, 83(2), 215–217. Retrieved February 23, 2017, from https://www.aafp.org/afp/2011/0115/p214.html external link

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.

Citations

  1. Elixhauser, A., & Wier, L.M. (2011). Complicating conditions of pregnancy and childbirth, 2008. HCUP Statistical Brief #113. Rockville, MD: Agency for Healthcare Research and Quality. Retrieved February 23, 2017, from http://www.hcup-us.ahrq.gov/reports/statbriefs/sb113.pdf (PDF 292 KB)
  2. Stranges, E., Wier, L. M., & Elixhauser, A. (2012). Complicating conditions of vaginal deliveries and cesarean sections, 2009. HCUP Statistical Brief #131. Rockville, MD: Agency for Healthcare Research and Quality. Retrieved February 23, 2017, from http://www.hcup-us.ahrq.gov/reports/statbriefs/sb131.pdf (PDF 291 KB)
  3. Shields, S. G., Ratcliffe, S. D., Fontaine, P., & Leeman, L. (2007). Dystocia in nulliparous women. American Family Physician, 75(11), 1671–1678. Retrieved February 23, 2017, from http://www.aafp.org/afp/2007/0601/p1671.html
  4. American College of Obstetricians and Gynecologists. (2016). Ob-gyns can prevent and manage obstetric lacerations during vaginal delivery, says new ACOG Practice Bulletin. Retrieved February 16, 2017, from http://www.acog.org/About-ACOG/News-Room/Ne="ws-Releases/2016/Ob-Gyns-Can-Prevent-and-Manage-Obstetric-Lacerations external link
  5. World Health Organization. (2007). Managing complications in pregnancy and childbirth: A guide for midwives and doctors. Retrieved February 16, 2017, from https://apps.who.int/iris/bitstream/handle/10665/43972/9241545879_eng.pdf external link (PDF 5.47 MB)
  6. MedlinePlus.(2016). Episiotomy. Retrieved April 17, 2017, from https://medlineplus.gov/ency/patientinstructions/000482.htm
  7. MedlinePlus.(2016). Premature rupture of membranes. Retrieved February 16, 2017, from https://medlineplus.gov/ency/patientinstructions/000512.htm
  8. American College of Obstetricians and Gynecologists. (2008). ACOG guidelines on premature rupture of membranes. American Family Physician, 77(2), 245–246. Retrieved February 23, 2017, from http://www.aafp.org/afp/2008/0115/p245a.html external link
  9. American College of Obstetricians and Gynecologists. (2006; reaffirmed 2015). ACOG Practice Bulletin: Clinical management guidelines for obstetrician-gynecologists number 76, October 2006: Postpartum hemorrhage. Obstetrics & Gynecology, 108(4), 1039–1047. Retrieved August 7, 2017, from https://www.ncbi.nlm.nih.gov/pubmed/17012482

NICHD Labor and Delivery Research Goals

Healthy, safe labor and delivery are fundamental to maximizing health for women and infants in both the short term and the long term.

NICHD research on labor and delivery addresses the following topics, among others:

  • Basic biology of labor and how labor progresses
  • How to determine the appropriate time for a cesarean delivery when labor does not progress
  • New, evidence-based definitions of labor protraction and arrest
  • 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

Labor and Delivery Research Activities and Advances

Through its intramural and extramural organizational units, NICHD supports and conducts a variety of research on labor and delivery.

Division of Extramural Research (DER)

Several organizational units within the DER support research on labor and delivery:

The Pregnancy and Perinatology Branch (PPB) seeks to improve the health of mothers and children by supporting research in several areas related to pregnancy, including labor and delivery. PPB-supported studies examine the development of the placenta and how it relates to labor and delivery outcomes; racial and ethnic disparities in preterm birth rates; adverse effects of oxytocin receptor desensitization due to prolonged oxytocin infusion during labor induction; molecular mechanisms of uterine contractions during normal labor, preterm labor, and post-term pregnancies; neural regulation of pre-partum cervical ripening; comparative effectiveness of antibiotics for cesarean delivery; development of improved labor diagnostic devices; obstetrical determinants of neonatal survival; and labor induction versus expectant management in post-term pregnancy.

  • PPB-supported finding: Even a partial steroid treatment can improve survival and longer-term health among extremely preterm infants, researchers in NICHD's Neonatal Research Network found. A 48-hour course of steroids helps the lungs and other organs develop, improving survival for infants born at 22 to 27 weeks of pregnancy. But what a provider should do when not enough time is available to complete treatment before delivery has not been clear. After examining about 6,000 cases, the researchers found that mothers who received some treatment were more likely than those who did not to give birth to infants who survived, and their infants had fewer birth complications and developmental disabilities 1.5 years and nearly 2 years after birth. (PMID: 27723868)
  • PPB-supported finding: When cesarean delivery is unplanned, adding a second antibiotic to standard measures to prevent infection could reduce infection rates by half. About 12% of women who undergo unplanned surgery to deliver their baby develop an infection. After studying more than 2,000 deliveries, researchers funded by NICHD found that 6.1% of women given the standard antibiotic treatment, cephalosporin, plus a second antibiotic, azithromycin, later developed an infection, compared with 12% of women receiving only cephalosporin. (PMID: 28076707)

The Obstetric and Pediatric Pharmacology and Therapeutics Branch (OPPTB) supports obstetric clinical trials, including studies of algorithms for simulation and new methods for using medical record data, and other research that can improve understanding of how to appropriately use pharmaceuticals during pregnancy, including medications commonly used during labor and delivery.

The Maternal and Pediatric Infectious Disease Branch (MPIDB) supports and conducts a wide range of domestic and international research related to the epidemiology, diagnosis, clinical manifestations, pathogenesis, transmission, treatment, and prevention of emerging infectious diseases such as Zika virus, HIV infection. MPIDB also supports and conducts research on infectious and non-infectious complications associated with HIV in pregnant women, infants, and the family unit as a whole. For example, MPIDB-supported researchers are investigating how tenofovir vaginal gel, a medication given during pregnancy, works to treat HIV and to prevent transmission of the virus from mother to child.

The Population Dynamics Branch supports research on demography, reproductive health, and population health. Current studies are examining the effect of mode of first delivery on subsequent childbearing and the role of prenatal employment in health care choices and services during childbirth.

Division of Population Health Research (DiPHR)

DiPHR conducts research to identify critical data gaps and designs research initiatives to answer etiologic questions or to evaluate interventions aimed at modifying behavior related to public health.

The Consortium on Safe Labor (CSL), led by researchers within the DiPHR's Epidemiology Branch, is an observational study whose goals are to explore the underlying causes of the high cesarean delivery rate in the U.S. population, describe contemporary labor progression at the national level, determine when is the most appropriate time to perform a cesarean delivery in women with labor protraction and arrest, and examine air quality and its effect on reproductive health and birth outcomes. The CSL includes 12 clinical centers and 228,562 pregnancies from across the United States. CSL research findings include the following:

  • Compared with women who have a typical first-time pregnancy, women who attempt labor after a previous cesarean delivery experience a slower progression of labor, especially during the stages when the cervix dilates from 4 to 7 or 8 centimeters. A better understanding of the typical progression of labor could help providers better manage labor and delivery in a variety of circumstances. (PMID: 25935774)
  • Women spend more time in labor now than approximately 50 years ago. The implication of this finding is that preventing cesarean delivery in the first pregnancy will go a long way toward decreasing the national cesarean delivery rate. Because providers are using definitions of "abnormal labor" developed in a population of women who are different from the contemporary obstetrical population, the CSL findings suggest that routine interventions, such as the use of oxytocin and timing of cesarean delivery, as well as modern-day labor process management, warrant reconsideration. (PMID: 22542117)
  • prolonged second stage of labor was associated with highly successful vaginal delivery rates but also with small increases in maternal and serious neonatal morbidity, as well as perinatal mortality in deliveries without an epidural. Investigators assessed neonatal and maternal outcomes when the second stage—the time from when pushing begins until delivery of the baby—was prolonged, according to American College of Obstetricians and Gynecologists (ACOG) guidelines. The findings suggest that the benefits of vaginal delivery need to be weighed against the increased maternal and neonatal risks when second-stage labor lasts longer than described in the ACOG guidelines. (PMID: 24901265)
  • Certain nonmedical factors are common in cesarean deliveries. Researchers using CSL data studied medical records from more than 145,000 deliveries involving a trial of labor. The baby was delivered by C-section in about 20,000 cases. The researchers analyzed the impact of factors such as when the delivery occurred, certain provider characteristics, the type of insurance used, patient characteristics, and policies at the institution. They learned that delivery in the evening, a male provider, a nonwhite mother, and use of Medicaid were associated with cesarean delivery. Understanding how these factors affect decision making about delivery could help with the design of ways to reduce high cesarean rates. (PMID: 23670226)

Other areas of ongoing research include determining the optimal time for the second stage of labor and exploring how sociodemographic changes in the current obstetrical population have affected pregnancy complications; maternal and neonatal morbidity; and implications for clinical management, including delivery timing and route. Researchers are also exploring how chronic diseases, such as hypertension, diabetes, and asthma, affect these outcomes. Further work from the CSL study will help shape the future clinical care of pregnant women.

Division of Intramural Research (DIR)

The Program in Perinatal Research and Obstetrics (PPRO) within the DIR conducts clinical and laboratory research on maternal and fetal diseases responsible for excessive infant mortality in the United States.

NICHD's research related to Preterm Labor and Birth is covered in the Preterm Labor and Birth topic.

  • Global Network for Women's and Children's Health Research 
    This PPB-supported network is a partnership committed to improving maternal and infant health outcomes and building health research capacity in resource-poor settings by testing cost-effective, sustainable interventions. 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, promoting the use of corticosteroids to reduce newborn death, training birth attendants in techniques to increase infant survival, investigating the effect of nutritional interventions on infant health, and assessing the impact of ultrasound screening on maternal and infant health.
  • International Maternal, Pediatric, Adolescent AIDS Clinical Trials (IMPAACT) Network 
    The MPIDB-funded IMPAACT Network is a cooperative group of institutions, investigators, and other collaborators focused 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 
    This PPB-funded network was established in 1986 to respond to the need for 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.
  • National Child and Maternal Health Education Program (NCMHEP) 
    The NCMHEP Is It Worth It? Initiative describes the benefits to mother and baby of waiting until at least 39 weeks of pregnancy to deliver, unless it is medically necessary to deliver earlier. NCMHEP's Know Your Terms Initiative explains recent changes in the definition of "full term."
  • NICHD Domestic and International Pediatric and Maternal HIV Clinical Studies Network 
    This MPIDB-supported network conducts trials related to preventing and treating HIV infection and its complications in newborns and pregnant women.
  • NIH Consensus Development Conference Archive 
    For these conferences, independent panels of health professionals and public representatives prepared consensus and state-of-the-science statements based on the results of a systematic literature review.
  • Maternal and Pediatric Precision in Therapeutics (MPRINT) Hub 
    The OPPTB-supported OPRU Network provides the expert infrastructure needed to test therapeutic drugs during pregnancy. OPRU Network studies are investigating medications to alter uterine activity, such as those used to delay or prevent preterm birth and to treat gestational and type 2 diabetes, severe nausea, and other side effects of pregnancy and cancer as well as other series conditions in pregnant women.

Research activities and scientific advances in preterm labor and delivery are listed in the Preterm Labor and Birth topic.

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