Best Evidence: C-Section



Best evidence: When making important maternity decisions, women should have information from the best available research about the safety and effectiveness of different choices. In general, we can be most confident about results of systematic reviews that summarize randomized controlled trials (or RCTs, a type of study).

Unfortunately, for many decisions we must rely on less definitive research; and many important questions — even in the case of widely used drugs, tests and procedures — have hardly been studied at all. Although this situation is discouraging, an awareness of weak or missing evidence can help you make informed choices about care.

A best evidence review comparing the full range of risks to help you make a truly informed decision.

What is the bottom line?

What physical effects may occur in women more often with c-section?

What physical effects may occur in babies more often with c-section?

What role may c-section play in the development of childhood chronic disease?

What problems can only happen if a woman has a c-section?

What problems can only happen if a woman has a vaginal birth?

What emotional or psychological effects may differ between c-section and vaginal birth?

What are possible effects of c-sections on the woman in future pregnancies and births?

What are possible effects of a c-section scar on future babies?

Does cesarean delivery protect against sexual, urinary, and other problems related to the pelvic floor?

Does c-section protect against injuries to babies?



A best evidence review comparing the full range of risks to help you make a truly informed decision

Childbirth Connection carried out a best evidence review of research to help you make informed decisions about cesarean versus vaginal birth. While more high-quality studies are needed, a large body of studies already exists and sheds light on these questions for those who need guidance now. This section summarizes results of the most relevant and better quality studies among hundreds that were examined (see review reference at end of this page).

Since the decision about whether to have a vaginal birth or a cesarean section can impact you and your baby in many ways, it is essential that you understand expected benefits along with the full range of possible risks to you and your baby.

The information here covers a broad range of outcomes — physical as well as emotional effects in mothers and babies, and shorter- and longer-term risks (including any future pregnancies).

Even if you do not plan to have more children, you should be aware of risks for future pregnancies. Many women change their mind about becoming pregnant again or decide to carry through with an unplanned pregnancy.

What is the bottom line?

Which is safer: vaginal birth or c-section?
Vaginal birth is much safer than a c-section for most women and babies. Sometimes a c-section is the only safe option, like when the baby is positioned side-to-side in the belly (transverse lie) or the placenta is covering the cervix (placenta previa). In other situations, having a c-section might have some possible benefits, and these need to be weighed against the risks. You have the right to know these risks and possible benefits, and only you can decide how important they are to you.

What are the possible benefits of having a c-section?
The possible benefits depend on what’s going on in your pregnancy or labor. Your doctor or midwife might recommend a c-section if labor or vaginal birth could be particularly risky for you or your baby. For example, it can be difficult to birth a baby that is in a breech position, and some breech babies can get injured during vaginal birth. Or if the fetal heart rate has certain changes in labor, it could be a sign that the baby isn’t getting enough oxygen. In these special cases, a c-section may reduce the chance that your baby will be injured.

What are the possible benefits of having a vaginal birth?
Even though labor and vaginal birth can be hard work, they are generally easier on a woman’s body than a cesarean. Recovery after vaginal birth is usually shorter and less painful than after a c-section, and allows the woman to spend more time with her baby. New research is discovering ways that labor and vaginal birth are good for babies, too. The hormones that cause labor to start and progress actually help the baby get ready to be born, reducing the chance of problems like breathing difficulties. Babies that are born vaginally also have lower rates of some serious childhood diseases like asthma, diabetes, and allergies and are less likely to become obese. Researchers think these benefits have to do with healthy bacteria babies are exposed to during birth.

What are the possible harms of having a c-section?
There’s no getting around the fact that a c-section is surgery. All surgeries have risks, like infection, injury to blood vessels and organs, and serious bleeding. A c-section can also cause problems for babies, like breathing difficulties that need treatment in a newborn intensive care unit. Recovering after a c-section is also more difficult than after a vaginal birth.

C-sections can also cause certain ongoing problems. For example, c-sections can cause chronic pelvic pain in some women, and babies born by c-section are at increased risk of developing chronic childhood diseases like asthma and diabetes. These risks are discussed in more detail below.
   
What are the possible harms of having a vaginal birth?
Although the skin and tissues around the vagina can stretch quite a lot to allow a baby through, many women do have lacerations that need stitches. Most of these tears are minor and heal easily but a small number of women will have more serious tears that take longer to heal. Stretching and tearing can also cause weakness in the muscles that control urine and bowel movements, so some women will leak urine or feces in the weeks or months after giving birth, with a small number having problems that last longer. These problems are much more likely if the baby was delivered with a vacuum or forceps or if the woman had an episiotomy. Babies can experience certain types of nerve and bone injuries during vaginal birth. These are also more common with vacuum- and forceps-assisted births, and most injuries heal. These risks are discussed in more detail below.

Can how I have this baby affect my next baby?
Yes. The way you give birth can affect your next pregnancy in two ways: your choices and your safety.

Choices: Even though research shows that most women can safely have a vaginal birth after a cesarean (VBAC), some hospitals and health care providers will only offer a repeat cesarean. As a result, you are likely to have c-sections for all future births if you have a c-section in this birth. Even if you plan a VBAC, you might face fewer choices, such as where you can have your baby or which tests and procedures you will have.

Safety: Whether you have a c-section or plan a vaginal birth for any future babies, your pregnancy will be considered high-risk if you’ve had a c-section before. That’s because the c-section scar can cause problems with the new placenta. These problems can cause the baby to be born too early and too small, and can lead to serious bleeding problems for women. The more c-sections a woman has, the more likely these problems are. These risks are discussed in more detail below.

Even if you do not plan to have more babies, it is important to know about these risks, because many women change their minds or have unplanned pregnancies.

MORE DETAILED INFORMATION ABOUT RISKS NOTED ABOVE

Click below on VERY LARGE, LARGE, etc. to understand difference in level of risk between care options.

On the rest of this page, you will learn what the research says about the following questions:


What physical effects may occur in women more often with c-section?


  • maternal death: More women appear to die as a result of cesarean delivery (not from the problems that led to the surgery), but the excess number cannot be estimated from the studies examined.
  • cardiac arrest (heart attack): Limited evidence suggests that a MODERATE excess number of healthy women may experience cardiac arrest in association with cesarean delivery compared with similar women planning vaginal birth.
  • emergency hysterectomy (surgical removal of the uterus (womb) around the time of birth): A SMALL to MODERATE excess number of women having initial cesarean delivery undergo unplanned hysterectomy compared with women having vaginal birth.
  • blood clots in veins (can cause stroke or life-threatening breathing problems): A SMALL to MODERATE excess number of healthy women having cesarean delivery experience a blood clot.
  • anesthesia complications: Limited evidence suggests that a MODERATE excess number of healthy women having cesarean delivery may experience complications with anesthesia compared with similar women having spontaneous vaginal birth.
  • major infection: Limited evidence suggests that a MODERATE to LARGE excess number of healthy women having planned cesarean delivery experience major infection compared with women having or planning vaginal birth.
  • rare, life-threatening complications: Limited evidence suggests that more women experience certain rare complications that can cause life-threatening hemorrhage after cesarean than after vaginal birth, but the excess number cannot be estimated from the studies examined.
  • longer time in hospital: a woman who has a cesarean usually stays in the hospital a day or two longer than a woman who has a vaginal birth for post-operative monitoring and care, and this stay may be extended if she has complications.
    Added likelihood for a woman with a cesarean: VERY HIGH for a longer time in the hospital
  • wound infection (can be in the cesarean wound or a genital wound): A LARGE excess number of healthy women having cesarean delivery have wound infections compared with women planning vaginal birth.
  • hematoma (a painful blood-filled swelling in the cesarean wound or the genital wound): Limited evidence suggests that a LARGE excess number of healthy women having cesarean delivery have wound hematomas compared with women planning vaginal birth.
  • wound separation (the cesarean or genital wound stitches come open and have to be repaired): Limited evidence suggests that a SMALL excess number of healthy women having cesarean delivery have wound separation compared with women planning vaginal birth.
  • longer hospital stay: Planned cesarean delivery increases length of hospital stay by at least 0.6 to 2 days compared with planned vaginal birth.
  • going back into the hospital: A MODERATE to LARGE excess number of healthy women having cesarean delivery require readmission to the hospital.
  • problems with physical recovery: With the exception of hemorrhoids, which are more common with vaginal birth, a LARGE to VERY LARGE excess number of women having cesarean delivery experience problems with physical recovery, including general health, bodily pain, extreme tiredness, sleep problems, bowel problems, ability to carry out daily activities, and ability to perform strenuous activities, compared with women having spontaneous vaginal birth.
  • chronic (long-lasting) pelvic pain: More women experience chronic pelvic pain after cesarean delivery than after vaginal birth, but the excess number cannot be estimated from the studies examined.

What physical effects may occur in babies more often with c-section?

  • newborn death: Limited evidence suggests that babies of women having elective first cesareans may be at greater risk of neonatal death compared with low-risk women planning vaginal birth, but the excess number of deaths cannot be estimated from the study examined.
  • respiratory distress syndrome (a serious breathing problem that requires treatment in a neonatal intensive care unit): When birth occurs before 39 weeks, more babies born by cesarean than by vaginal birth experience respiratory distress syndrome (RDS), but the excess number cannot be estimated from the studies examined.
  • pulmonary hypertension (a serious breathing problem that requires treatment in the neonatal intensive care unit): Limited evidence suggests that a MODERATE excess number of babies delivered by elective cesarean may develop pulmonary hypertension.
  • not breastfeeding: Conflicting evidence suggests that babies delivered by cesarean may be at excess risk of not being breastfed.

What role may c-section play in the development of childhood chronic disease?

  • asthma: Cesarean delivery increases the likelihood of developing asthma in childhood, but the excess number cannot be estimated from the studies examined.
  • type 1 diabetes: Cesarean delivery increases the likelihood of developing Type 1 diabetes in childhood, but the excess number cannot be estimated from the studies examined.
  • allergies (hay fever): Cesarean delivery increases the likelihood of developing childhood allergic rhinitis (hay fever), but the excess number cannot be estimated from the studies examined.
  • food allergy: Limited and conflicting evidence suggests that cesarean delivery may increase the likelihood of developing food allergy in childhood, but the excess number, if any, cannot be calculated from the studies examined.
  • obesity: Limited evidence suggests that a LARGE excess number of children delivered by cesarean may be obese at age 3.

What problems can only happen if the woman has a c-section?

  • injuries to the woman during surgery: Among women having first delivery via cesarean, a MODERATE number of women experience bladder puncture, and a SMALL number experience bowel injury or injury to a ureter.
  • injuries to the baby during surgery: Limited evidence suggests that a MODERATE number of babies are cut during cesarean delivery.
  • need for another surgery to treat problems from the c-section: Limited evidence suggests that a MODERATE number of women having cesarean delivery require re-operation.
  • ongoing pain at the site of the cesarean incision: Limited evidence suggests that a LARGE to VERY LARGE number of women still experience pain at the incision site 6-10 months or more after cesarean delivery.
  • cesarean scar endometriosis (painful growth of tissue): Limited evidence suggests that a SMALL to LARGE number of women having cesarean delivery develop cesarean scar endometriosis.
  • cesarean scar ectopic pregnancy (embryo or placenta grows inside the cesarean scar): Some women becoming pregnant after cesarean will experience a cesarean scar ectopic pregnancy or placental implantation within the uterine scar, but the number cannot be estimated from the studies examined.
  • surgical adhesions (scar tissue that can cause pain and make future surgeries more risky): Limited evidence suggests that a VERY LARGE number of women develop dense adhesions after cesarean delivery.

What problems can only happen if a woman has a vaginal birth?

  • injury to the muscle around the anus: A LARGE number of women experience anal sphincter injury at vaginal birth. 
  • injury to the vaginal or perineum (area between vagina and anus): A VERY LARGE number of women experience trauma to the perineum or genitals at vaginal birth that requires suturing.
  • ongoing pain in the perineum (area between vagina and anus): Limited evidence suggests that a LARGE number of women experience persistent perineal pain lasting at least six months with spontaneous vaginal birth, and a VERY LARGE number of women experience perineal pain lasting at least six months after instrumental vaginal delivery (vaginal birth assisted with forceps or vacuum).

What emotional or psychological effects may differ between c-section and vaginal birth?

  • negative effect on mother-child relationship: Data conflict about whether cesarean delivery has an adverse effect on the mother-child relationship.
  • depression: Data conflict on whether cesarean delivery increases the likelihood of postpartum depression.
  • posttraumatic distress: Data conflict but suggest that more women may experience PTSD or PTSD symptoms after cesarean delivery in general and unplanned cesareans in particular, but the excess number, if any, cannot be estimated from the studies examined.

What are possible effects of c-sections on women in future pregnancies and births?

All pregnant women should be aware of these risks. Many women who do not expect to have more children change their mind or decide to continue with an unplanned pregnancy.
  • problems getting pregnant: More women experience impaired fertility after prior cesarean delivery compared with after prior vaginal birth, but the excess number cannot be estimated from the studies examined.
  • choosing not to get pregnant: A LARGE to VERY LARGE excess number of women choose not to conceive again after cesarean delivery.
  • placenta previa (placenta grows over the cervix, which can cause serious bleeding, hysterectomy, and need for early delivery): A SMALL excess number of women with first delivery by cesarean develop placenta previa in the next pregnancy, but the excess number cannot be calculated from the studies examined. A LARGE excess number of women develop placenta previa after two or more prior cesareans.
  • placenta accreta (placenta grows into or through the wall of the uterus, which can cause serious bleeding, hysterectomy, and need for early delivery): A SMALL excess number of women with first delivery via cesarean develop placenta accreta in the next pregnancy. A LARGE excess number of women develop placenta accreta after multiple prior cesareans.
  • placental abruption (placenta begins to separate from the uterus before the baby is born, which can cause serious bleeding, injury to the baby, and need for early delivery): A MODERATE excess number of women with first delivery via cesarean have a placental abruption in subsequent pregnancies.
  • hysterectomy (surgical removal of the uterus (womb) around the time of birth): A MODERATE excess number of women with prior cesarean delivery require an urgent hysterectomy during the next delivery admission compared with women with only prior vaginal birth. Limited evidence suggests that the excess increases with subsequent pregnancies.
  • uterine rupture (the c-section scar separates, which can cause serious bleeding, injury to the baby, and hysterectomy): A MODERATE excess number of women will experience uterine rupture with prior cesarean delivery compared with prior vaginal birth.
  • admission of the woman to an intensive care unit: Limited evidence suggests that a LARGE excess number of women with prior cesarean are admitted to intensive care at the next delivery compared with women with prior vaginal birth.
  • going back to the hospital: Limited evidence suggests that a MODERATE excess number of women with prior cesarean are readmitted to the hospital after discharge at the next delivery compared with women with prior vaginal birth.

What are possible effects of a c-section scar on future babies?

  • stillbirth: Data conflict, but suggest that a SMALL to MODERATE excess number of babies developing in a uterus with a cesarean scar are stillborn.
  • death in late pregnancy or in the first week of life: Data conflict, but suggest that more babies developing in a uterus with a cesarean scar may die late in pregnancy or during the first week after birth, but the excess number, if any, cannot be estimated from the studies examined.
  • Preterm birth (less than 37 weeks) and low birth weight (less than 5 lb 0 oz or 2500 grams): Data conflict on whether prior cesarean delivery imposes increased risk of preterm birth and concomitant low birth weight.
  • small for gestational age (underweight for the number of weeks at which the baby is born): Data conflict on whether prior cesarean delivery imposes increased risk of the baby being small for gestational age in the next pregnancy compared with prior vaginal birth.
  • need for assistance with breathing: Limited evidence suggests that a LARGE excess number of babies whose mothers had prior cesarean may require ventilation at birth compared with babies whose mothers had prior vaginal birth.
  • hospital stay longer than 7 days: Limited evidence suggests that a LARGE excess number of babies whose mothers had prior cesarean have hospital stays of more than 7 days compared with babies whose mothers had prior vaginal birth.

Does c-section protect against sexual, bowel, urinary, and pelvic floor problems?

Relationship between care during birth and pelvic floor (a hammock of muscles that support the internal organs) problems: Research finds that some practices used at the time of pushing and during the birth increase the likelihood of pelvic floor injury or weakness and related problems. Many women experience one or more of these during vaginal birth. You can reduce your risk pelvic floor problems by choosing a caregiver and birth setting with low rates of these practices, including:
•    cutting an episiotomy
•    using vacuum extraction or forceps to help deliver the baby
•    having women give birth while lying on their backs
•    using caregiver-directed pushing, which is often more forceful than having the woman and her own reflexes guide pushing
•    pressing on the woman's abdomen to help move the baby out
•    not guiding women to birth the baby’s head slowly and gently
Among all the studies examined that compared the effects of vaginal versus cesarean birth on pelvic floor problems, not one considered the harmful impact of all of these practices, and some didn’t take any of them into account. For this reason, we don’t know how many problems are caused by vaginal birth itself and how many are caused by harmful avoidable practices.

Preventing Pelvic Floor Dysfunction is a full Pregnancy Topic on this important issue.
  • sexual dysfunction: Cesarean delivery provides minimal or no protection against sexual dysfunction.
  • bowel incontinence (decreased ability to control loss of gas or, more rarely, feces from the anus): Cesarean delivery provides no protection against anal incontinence in either the short term or up to 12 years after birth; planned cesarean provides no protection compared with cesareans during labor.
  • Urinary incontinence (decreased ability to control loss of urine. Urge incontinence happens when the urge to urinate comes on suddenly and the person cannot control it long enough to get to a bathroom in time. Stress incontinence happens when coughing, laughing, or sneezing causes the person to leak urine)
    • Data conflict but suggest that cesarean delivery may provide some protection against urinary urge incontinence of any degree in the short term, but protective effect, if any, has disappeared by one year after birth, and similar percentages experience severe incontinence.
    • A LARGE to VERY LARGE excess number of women having vaginal birth experience urinary stress incontinence of any degree at one year or more after birth compared with women having cesarean delivery, but rates of severe incontinence are low and similar between cesarean and vaginal birth groups.
  • symptomatic pelvic organ prolapse (the pelvic floor muscles and organs sag down into the vagina): A LARGE excess number of women having vaginal birth experience symptomatic pelvic floor prolapse compared with women having only cesarean delivery. The excess increases as the number of vaginal births increases and with instrumental vaginal delivery compared with spontaneous vaginal birth.

Does c-section protect against injuries to babies?

  • brachial plexus injury (injury to the nerves that allow the shoulder and arm to move): Limited evidence suggests that a MODERATE excess number of babies born vaginally experience brachial plexus injury compared with babies delivered by cesarean, but the excess is influenced by whether delivery is spontaneous vaginal, instrumental vaginal, or cesarean after failed instrumental delivery.
  • facial nerve injury (injury to the nerves in the face): Limited evidence suggests that facial nerve injury rates do not differ by whether the birth was vaginal or cesarean.
  • brain injury: Cesarean delivery provides no protection from bleeding inside the brain or symptoms of brain injury such as seizure.
  • cerebral palsy: Limited evidence suggests that liberal use of cesarean delivery is not associated with a reduction in cerebral palsy rates.

    Reference

    Childbirth Connection (2012). Vaginal or Cesarean Birth: What Is at Stake for Women and Babies? New York: Childbirth Connection. Available at: http://transform.childbirthconnection.org/reports/cesarean/



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    Childbirth Connection is a national not-for-profit organization founded in 1918 as Maternity Center Association. Our mission is to improve the quality of maternity care through research, education, advocacy and policy. Childbirth Connection promotes safe, effective and satisfying evidence-based maternity care and is a voice for the needs and interests of childbearing families.
    Most recent page update: 12/10/2012