Breech Birth

Definition

In a breech birth, the presenting part of the fetus, or the part that enters the woman's birth canal first, is the buttocks or leg(s).

Description

In almost 97% of vaginal births, the head is the part of the baby to be born first (i.e., vertex presentation). During a woman's pregnancy, the fetus moves freely inside the uterus, cushioned by the amniotic fluid. At 20 weeks' gestation, the midway point in the pregnancy, about 24% of fetuses are in a breech position. By 34 weeks, only about 7% are in a breech position. As the pregnancy progresses towards term (37-42 weeks), the growing fetus has less room in which to turn around, and usually remains more in an inverted (head down) position. However, in about 3-4% of births, the buttocks or feet present first.

There are three types of breech presentations:

·         Complete breech, in which the buttocks present first, the baby's thighs are tight against the abdomen, the legs are crossed, and the feet are flexed. In this position, the fetus is curled up tightly in a ball.

·         Frank breech, in which the knees are straight (i.e., not bent), and the legs are held tightly against the abdomen and head. This breech position comes closest to filling the pelvic inlet, as would the fetus's head.

·         Footling breech, in which one or both legs enter the birth canal first. The fetus appears to be standing in an upright position.

Risks

Risks of a vaginal breech delivery include:

·         Prolapse of the umbilical cord. This is especially true in a footling presentation, where the feet and legs are small and provide room for the umbilical cord to slip alongside and into the birth canal. Any pressure on the cord compresses the sides of the cord, decreasing blood flow and oxygen to the fetus. This may result in anoxia.

·         Entrapment of the head. This occurs when the body of the neonate passes through the cervix, but the head, which is the largest part of the body, cannot fit through the cervical opening. This may occur because the cervix was incompletely dilated at the time of the birth of the baby, or when the head is larger than the pelvic opening.

·         Trauma to the head or neck of the neonate during delivery. This could result in permanent brain damage or paralysis of the infant.

·         Trauma to the spine or an arm resulting in fracture of a bone.

·         Meconium aspiration. The breech position may cause an early rupture of the amniotic fluid membranes, and meconium (the infant's first stool) may be released. If the neonate breathes in any of the meconium, he or she risks obstruction of the airway by the meconium, and pneumonia.

·         Dysfunctional labor. Because of the fetal breech position, the labor can be drawn out, exhausting the mother, and diminishing her ability to push as the time of delivery approaches.

·         Higher level of perinatal morbidity and mortality.

Accurate imaging of the fetus in utero has decreased the number of breech births by alerting obstetricians and midwives to this presentation prior to the time of delivery. A technique called external version may be used to encourage the fetus to rotate into a vertex position. However, as the practice of external version has increased, practitioners have had less experience delivering a breech baby vaginally. A successful vaginal delivery of a breech presentation depends to a great extent on the skill and experience of the practitioner.

Twins present a special challenge, and will take one of several possible birth positions:

·         Vertex-vertex. In this, the safest of positions for delivery, the twins both present in the vertex, or head down position. It occurs in about 40-45% of twin births.

·         Vertex-breech or breech-vertex. This position offers the most efficient use of the uterine space, but is not the best presentation for delivery. Vertex-breech and vertex-transverse positions occur in about 35-40% of twin births. Breech-vertex positioning occurs in about 15-20% of births.

·         Breech-breech presentation occurs in about 15-20% of twin births, and almost always results in cesarian section birth.

If the second twin entering the birth canal is the larger, there will be a concern that he or she may become stuck because the smaller, first twin did not adequately enlarge the cervical opening. Twins are often born prematurely, and are smaller than full-term infant. The more premature the infant, the greater the chance it will have a smaller body-to-head proportion than the full-term infant. This creates a greater hazard for breech birth, because the small body can come through a less-dilated cervix, and there is a greater chance that the head will get trapped. Accurate imaging of twin positions will play a major role in determining the safest delivery method. An external version of the second twin may be proposed. Version of the first twin in unlikely, as the procedure poses a threat to both twins.

 Causes and symptoms

The cause of a particular breech presentation may not be understood about 80% of the time. However, causes of breech presentation may include:

·         an inability of the fetus to have full movement inside the uterus

·         the position of the placenta, such as a low-lying placenta previa, and a short umbilical cord

·         decreased muscle tone of the fetus

·         a congenital disorder of the fetus, especially neuromuscular in nature

·         a space-related problem for the fetus, such as with uterine fibroids

·         fetal anomaly, such as hydrocephalus

·         uterine structural anomaly, such as a septum trapping the fetus in a breech position

·         gestation of less than 40 weeks

·         multiple gestation

·         hydramnios, a condition in which excess amniotic fluid is produced and the fetus has too much room in which to move

Diagnosis

There are three primary ways in which a breech position is discovered, including imaging, position of the fetal heartbeat, and external palpation on the mother's abdomen.

Imaging. There are a variety of imaging technologies, varying in safety, cost, and ease of access. Magnetic resonance imaging (MRI) is very accurate, but is extremely expensive, not as readily available, and would rarely provide more information than an ultrasound to justify its use. Ultrasound is the most widely used method of imaging during pregnancy, as it uses sound waves instead of radiation, is available in most health care centers, and is cost efficient. Ultrasound is considered safe to use at all stages in pregnancy.

Leopold's maneuvers consist of a series of four external palpations of the mother's abdomen to determine fetal position in the uterus. The fetal head is hard and can move separately from the rest of the body. The buttocks feel soft and move with the body. As the time for delivery draws near, a vaginal examination may be required, however, as Leopold's maneuvers can sometimes be misleading. In a vaginal examination, the baby's fontanelles are palpated.

 Treatment

When dealing with a breech presentation, there are three choices for delivery: attempt to rotate the fetus into a vertex presentation prior to delivery; attempt a trial of vaginal delivery in the breech position; or deliver by cesarian section. Some hospitals may not have the mother attempt a vaginal delivery and instead opt for cesarian section.

The preferred mode of delivery is a vaginal birth with the fetus in vertex presentation. Attempts are therefore made to rotate the fetus from a breech into a vertex position. One method has been to have the mother assume different positions (e.g., knee-chest) in the hope that this would cause the fetus to move into a more favorable position. Research studies have not shown this to be very successful, although periodic anecdotal accounts of success have been reported. In the November 11, 1998, issue of the Journal of the American Medical Association, researchers reported on the use of traditional Chinese medicine to cause the fetus to rotate. In this study, moxa, a combustible Chinese herb, was used over a two-week period to stimulate an acupuncture point on the toe. Stimulation of this point is believed to increase fetal activity, during which the fetus then moves into the vertex position. After two weeks of treatment with moxa, 75% of the 130 fetuses studied rotated into the vertex position, while only 48% of the control (no intervention, just routine obstetrical care) fetuses rotated. However, the results of this study has not been replicated.

A more traditional and more commonly used treatment within Western medical standards is external version. In external version, the fetus is rotated manually by the physician, who exerts pressure on the mother's abdomen to cause the fetus to somersault into the vertex position. Medication may be given to the mother to relax the uterine muscles prior to the procedure. The vertex position allows the fetus more mobility and decreases the chance of uterine contractions, which lead to early labor. Before attempting version, however, an ultrasound is performed to confirm the position of the fetus. The timing of version is important. Done too early, the fetus may rotate back into a breech position if too much space is still available. Performed at 35-37 weeks gestation, the success rate has shown to be up to 65%. In approximately 1-2% of cases, complications arise following version, leading to the need for immediate delivery via cesarian section.

Version should always be done in a hospital, where there are facilities for immediate cesarian delivery available in the cases of cord compression or placental abruption. Some research has indicated that giving the mother an epidural for the version procedure increases its success rate. The version can be accomplished by two health care professionals. Mineral oil may be applied to the mother's abdomen so that the obstetrician's hands can smoothly slide over the surface. The fetal heart rate should be monitored closely for any signs of fetal distress, and should be continued for about an hour after the procedure to assure fetal stability. Mothers who are Rh-negative may be given Rh immune globulin, which would prevent incompatibility should fetal-to-mother transfusion occur during the version. About 90% of babies turned by version will remain in this position for delivery.

 

Version has risks and is contraindicated in the following situations:

·         uterine structural anomalies

·         third-trimester bleeding

·         hydramnios, excess amniotic fluid production

·         nuchal cord, or the cord around the baby's neck, (not always seen on ultrasound)

·         previous uterine surgery, such as cesarian section, that has weakened the uterine walls

·         cephalopelvic disproportion (CPD), a condition in which the baby's head is too big for the mother's pelvic inlet, as evidenced on ultrasound or other imaging tools

When a vaginal breech birth is attempted, the pace of the delivery is very important. Fetal heart rate and uterine contractions need to be closely monitored. During a vertex vaginal delivery, the head is molded coming down the birth canal, and the labor process slows the pace of the delivery. In a breech vaginal birth, the smaller body may slip more quickly through the canal. If the head becomes caught, fetal anoxia (lack of oxygen) can occur. The head does not mold during a rapid breech birth, and if the neonate is allowed to deliver quickly, perhaps due to a detected prolapsed cord, the rapid change in pressure can result in intracranial hemorrhage. To assist the breech delivery, the mother may be asked to assume a squatting position, as this increases the birth canal volume by about 28%. (This position is not popular in the United States.) Forceps may be used to protect the neonate's neck and head from trauma and to assist in the delivery. If the vaginal birth attempt causes fetal distress, an emergency cesarian delivery may be required.

In a cesarian birth, an incision is made through the mother's abdominal wall into the uterus. The amniotic fluid membranes are broken and the neonate is extracted. A vertical incision in the uterus along the mother's abdominal midline is called a classical cut. This provides the fastest access to the infant and may be chosen in the event of an emergency delivery. The fetus can be removed from the uterus in minutes. If a woman has had the classical uterine incision, she will not be allowed to attempt to deliver vaginally in the future, because the uterine wall rupture can during the next labor. When time permits, the preferred incision is a transverse one, just above the pubic bone. This incision is sometimes referred to as a bikini cut. Healing time is decreased and may allow a woman to successfully deliver vaginally in the future.

KEY TERMS Cephalopelvic disproportion— When the fetus' head is larger than the mother's pelvic inlet. Nuchal cord— The term used when the umbilical cord is looped around the fetus' neck in utero. Presentation— Presentation refers to that part of the fetus' body that enters into the birth canal first. Prolapsed umbilical cord— When the cord falls into the birth canal, and may even hang out of the mother's vagina. This can cause compression of the cord and lead to decreased oxygen and blood flow to the fetus. Transverse— In the transverse position, the fetus lies sideways against the birth canal, with a shoulder or arm possibly entering the canal.

 Prognosis

About half the attempts of a vaginal breech delivery will result in a cesarian birth. Discovery of breech presentation prior to the time of delivery allows attempts to be made to rotate the fetus. If these attempts prove unsuccessful, a cesarian birth can then be scheduled. A scheduled cesarian allows the mother and her partner to be informed and participate, to some degree, in the process. Anesthesia can be chosen that allows the mother to be awake during the birth of her child. If emergency cesarian delivery is required, the mother will be given a general anesthesia to shorten the time required to extract the fetus in distress. If complications do not occur, the prognosis is excellent.

Health care team roles

During a breech birth more nursing personnel may be needed to assist the obstetrician and provide support for the mother. A neonate that has been in a breech position in utero may maintain an unusual position for a few days after birth. An explanation by the nurse can greatly reduce the mother's concern that there is something wrong with her baby.

Prevention

None of the known causes of breech presentation mentioned above are preventable, and in many breech presentations, there is no known cause. However, while it is not possible to prevent this presentation, attempts such as version are made to prevent a breech delivery, or to minimize its inherent risks.

Resources

BOOKS

Creasy, Robert K. and Robert Resnik. Maternal-fetal medicine. Philadelphia, Pennsylvania: W. B. Saunders Company, 1999.

Feinbloom, Richard I. Pregnancy, birth, and the early months, 3rd ed. Cambridge, Massachusetts: Perseus Publishing, 2000.

Pillitteri, Adele. Maternal & child health nursing: care of the childbearing & child rearing family, 3rd ed. Philadelphia, PA: Lippincott, 1999.

PERIODICALS

Cardini, F. and H. Weixin. "Moxibustion for correction of breech presentation: a randomized controlled trial." Journal of the American Medical Association 11 (November 1998): 1580-84.