Name = PAGENAME
DiseasesDB = 1631
MedlinePlus = 002060
eMedicineSubj = med
eMedicineTopic = 3272
eMedicine_mult = eMedicine2|emerg|868
A breech birth (also known as breech presentation) refers to the position of the
babyin the uterussuch that it will be delivered buttocksfirst as opposed to the normal headfirst position.
Certain factors can encourage a breech presentation. Prematurity is likely the chief cause. Twenty five percent of babies are in the breech position at 32 weeks gestation; this drops to three percent at term. The increasing baby size near term traps the fetus into the head down position normally. Pregnancies ending prematurely simply recruit more breeches before they can turn to head down. Factors predisposing to term breech presentation include:
* multiple (or multifetal) pregnancy (twins, triplets or more)
* excessive amounts of
* fetal anomalies: hydrocephaly,
anencephalyand other congenital abnormalities
* uterine abnormalities.
It is postulated that the baby normally assumes a head down presentation because of the weight of the baby's head. As the mass of the fetal head is the same as that of the pelvis, it is more likely that the enlarging fetus is more and more restricted in its movements, and simply becomes entrapped. The shape of the uterus is a more likely determinant of the final fetal presentation as uterine shape anomalies are strong predictors of breech presentation and other malpresentations.
Researchers generally cite a breech presentation frequency at term of 3-4% [link not accessible: http://www.rwh.org.au/rwhcpg/maternity.cfm?doc_id=7857] [ [http://www.dadlnet.dk/dmb/DMB_2005/0405/0405-disputatser/DMB3761.htm Breech at term, Early and late consequences of mode of delivery, Lone Krebs] , Danish Medical Bulletin - No. 4. November 2005. Vol. 52 Pages 234-52] at the onset of labour though some claim a frequency as high as 7% [ [http://www.emedicine.com/emerg/topic868.htm Pregnancy, Breech Delivery] , emedicine.com] . When labour is premature, the incidence of breech presentation is higher. At 28 weeks' gestation 25% of babies are breech, and the percentage decreases approaching term (40 weeks' gestation).
There are four main categories of breech births:
* Frank breech - the baby's bottom comes first, and his or her legs are flexed at the hip and extended at the knees (with feet near the ears). 65-70% of breech babies are in the frank breech position.
* Complete breech - the baby's hips and knees are flexed so that the baby is sitting crosslegged, with feet beside the bottom.
* Footling breech - one or both feet come first, with the bottom at a higher position. This is rare at term but relatively common with premature fetuses.
* Kneeling breech - the baby is in a kneeling position, with one or both legs extended at the hips and flexed at the knees. This is extremely rare.
Process of breech birth
As in labour with a baby in a normal head-down position, uterine contractions typically occur at regular intervals and gradually cause the
cervixto become thinner and to open. In the more common breech presentations, the baby’s bottom (rather than feet or knees) is what is first to descend through the maternal pelvisand emerge from the vagina.
At the beginning of labour, the baby is generally in an
obliqueposition, facing either the right or left side of the mother's back. As the baby's bottom is the same size in the term baby as the baby's head. Descent is thus as for the presenting fetal head and delay in descent is a cardinal sign of possible problems with the delivery of the head.
In order to begin the birth, internal rotation needs to occur. This happens when the mother's
pelvic floormuscles cause the baby to turn so that it can be born with one hip directly in front of the other. At this point the baby is facing one of the mother's inner thighs. Then, the shoulders follow the same path as the hips did. At this time the baby usually turns to face the mother's back. Next occurs external rotation, which is when the shoulders emerge as the baby’s head enters the maternal pelvis. The combination of maternal muscle tone and uterine contractions cause the baby’s head to flex, chin to chest. Then the faceemerges, and finally the back of the baby's head.
Due to the increased
pressureduring labour and birth, it is normal for the baby's leading hip to be bruised and genitaliato be swollen; this usually resolves shortly after birth.
Babies who assumed the frank breech position in utero may continue to hold their legs in this position for some days after birth - this is normal.
cord prolapsemay occur, particularly in the complete, footling, or kneeling breech. This is caused by the lowermost parts of the baby not completely filling the space of the dilated cervix. When the waters break the amniotic sac, it is possible for the umbilical cord to drop down and become compressed. This complication severely diminishes oxygenflow to the baby and the baby must be delivered immediately (usually by Caesarean section) so that he or she can breathe. If there is a delay in delivery, the brain can be damaged. Among full-term, head down babies, cord prolapse is quite rare, occurring in 0.4 percent. Among frank breech babies the incidence is 0.5 percent, among complete breeches 4-6 percent, and among footling breeches 15-18 percent. Head entrapmentis caused the failure of the fetal head to negotiate the maternal pelvis. At full term, the bitrochanteric diameter (the distance between the outer points of the hips) is about the same as the biparietal diameter (the transverse diameter of the skull)- simply put the size of the hips are the same as the size of the head. The relatively larger buttocks dilate the cervix as effectively as the head does in the typical head-down presentation. The relative head size of a premature fetus is significantly greater that the fetal buttocks. If the baby is premature, it may be possible for the baby’s body to emerge while the cervix has not dilated enough for the head to emerge.
Because the umbilical cord—the baby’s oxygen supply—is significantly compressed while the head is in the pelvis during a breech birth, it is important that the delivery of the aftercoming fetal head not be delayed. The head only just fits through the pelvis, and if the arm is extended alongside the head, delivery will not occur. If this occurs, the Lovset manoeuvre may be employed, or the arm may be manually brought to a position in front of the chest. The Lovset Manoeuvre works by rotating the fetal body by holding the fetal pelvis. Twisting the body such that an arm trails behind the shoulder, it will tend to cross down over the face to a position where it can be reached by the obstetrician's finger, and brought to a position below the head. A similar rotation in the opposite direction is made to deliver the other arm. In order to present the smallest diameter (9.5 cm) to the pelvis, the baby’s head must be flexed (chin to chest). If the head is in a deflexed position, the risk of entrapment is increased. Uterine contractions and maternal muscle tone encourage the head to flex. If the birth attendant pulls on the baby’s body, this action may deflex the head.
Oxygen deprivationmay occur from either cord prolapse or prolonged compression of the cord during birth, as in head entrapment. If oxygen deprivationis prolonged, it may cause permanent neurologicaldamage or death. Injuryto the brainand skullmay occur due to the rapid passage of the baby's head through the mother's pelvis. This causes rapid decompression of the baby's head. In contrast, a baby going through labor in the head-down position usually experiences gradual molding (temporary reshaping of the skull) over the course of a few hours. This sudden compression and decompression in breech birth may cause no problems at all, but it can injure the brain. This injury is more likely in pretermbabies. The fetal head may be controlled by a special two handed grip call the Morisseau-Smellie-Veit manoeuvre or the elective application of forceps. This will be of value in controlling the rate of delivery of the head and reduce decompression.
Squeezing the baby’s abdomen can damage internal organs. Positioning the baby incorrectly while using forceps to deliver the aftercoming head can damage the spine or spinal cord. It is important for the birth attendant to be knowledgeable, skilled, and experienced with all variations of breech birth. In the United States, because Cesarean section is increasingly being used for breech babies, fewer and fewer birth attendants are developing these skills.
Injury may occur even if a birth attendant uses appropriate interventions during labour. A majority of full-term term frank breech babies would be born without problems even without assistance. However, in a minority of cases, expert assistance is needed for the baby to be born safely. This must be placed in perspective. It is this minority that determines the safety of the choice of vaginal delivery of the breech. A fetal death rate as low as 1% might be acceptable to some societies if a greater benefit could accrue. Take a country like the United States with a population of 300 million, and a 14.14/1000 birth rate, assume a 3% breech rate, and the aforementioned 1% mortality. This would result in an annual attributable death rate from breech delivery of 1,273 babies per year. Attributable death rate implies that the deaths occurred because of the selection of vaginal delivery and not from concurrent problems, such as congenital abnormalities or prematurity.
Factors influencing the safety
*Type of breech presentation - the frank breech has the most favorable outcomes in vaginal birth, with many studies suggesting no difference in outcome compared to head down babies. (Some studies, however, find that planned caesarean sections for all breech babies improve outcome. The difference may rest in part on the skill of the doctors who delivered babies in different studies.) Complete breech presentation is the next most favorable position, but these babies sometimes shift and become footling breeches during labour. Footling and kneeling breeches have a higher risk of cord prolapse and head entrapment.
Parity- Parity refers to the number of times a woman has given birth before. If a woman has given birth vaginally, her pelvis has "proven" it is big enough to allow a baby of that baby's size to pass through it. However, a head-down baby's head often molds (shifts its shape to fit the maternal pelvis) and so may present a smaller diameter than the same size baby born breech. Research on the issue has been contradictory as far as whether vaginal breech birth is safer when the mother has given birth before, or not.
Fetal sizein relation to maternal pelvic size - If the mother's pelvis is roomy and the baby is not large, this is favorable for vaginal breech delivery. However, prenatal estimates of the size of the baby and the size of the pelvis are unreliable.
Hyperextensionof the fetal head- this can be evaluated with ultrasound. Less than 5% of breech babies have their heads in the "star gazing" position, face looking straight upwards and the back of the head resting against the back of the neck. Caesarean delivery is absolutely necessary, because vaginal birth with the baby's head in this position confers a high risk of spinal cord trauma and death.
Maturityof the Baby - Premature babies appear to be at higher risk of complications if delivered vaginally than if delivered by caesarean section.
*Progress of Labour - A spontaneous, normally progressing, straightforward labour requiring no intervention is a favourable sign.
twins- If a first twin is born head down and the second twin is breech, the chances are good that the second twin can have a safe breech birth.
*Birth attendant's skill (and experience with breech birth) - The skill of the doctor or midwife and the number of breech births previously assisted is of crucial importance. Many of the dangers in vaginal birth for breech babies come from mistakes made by birth attendants.
Turning the baby to avoid breech birth
There are many methods which have been attempted with the aim of turning breech babies, with varying degrees of success:
External cephalic versionwhere a midwife or doctor turns the baby by manipulating the baby through the mother's abdomen. ECV has a success rate between 40 - 70% depending on practitioner (Goer, 1995, 111) The fetal heart is monitored after the turn attempt, usually in the context of an institutional protocol. Studies show that turning the baby at term (after 36 weeks) is effective in reducing the number of babies born in the breech position. [ [http://www.cochrane.org/reviews/en/ab000083.html External cephalic version for breech presentation at term] Hofmeyr GJ, Kulier R, cochrane.org] Complications from external cephalic version are rare. Studies have also shown that attempting to turn the baby prior to this point has no impact on the presentation at term. [http://www.cochrane.org/reviews/en/ab000051.html Cephalic version by postural management for breech presentation] Hofmeyr GJ, Kulier R, cochrane.org]
Various manoeuvres are suggested to assist spontaneous version of a breech presenting pregnancy. These include maternal positioning or other exercises. A study has shown that there is insufficient evidence as to the benefit of maternal positioning in reducing the incidence of breech presentation.
Breech birth versus Caesarean section
Caesarean sectionis the most common way to deliver a breech baby in the USA, Australia, and Great Britain. Like any major surgery, it involves risks. Maternalmortality is increased by a Caesarean section, but still remains a rare complication in the First World. Third World statistics are dramatically different,and mortality is increased significantly. There is remote risk of injury to the mother's internal organs, injury to the baby, and severe hemorrhage requiring hysterectomywith resultant infertility. More commonly seen are problems with noncatastrophic bleeding, postoperative infection and wound healing problems.
One large study has confirmed that elective cesarean section has lower risk to the fetus and a slightly increased risk to the mother, than planned vaginal delivery of the breech [ [http://www.cochrane.org/reviews/en/ab000166.html Planned caesarean section for term breech delivery] , Hofmeyr GJ, Hannah ME, cochrane.org] however elements of the methodology used have undergone some criticism. [When Research is Flawed:Planned Vaginal Birth versus Elective Cesarean for Breech Presentation [http://www.lamaze.org/Research/WhenResearchisFlawed/VaginalBreechBirth/tabid/167/Default.aspx] ] [Inappropriateness of randomised trials for complex phenomena [http://www.bmj.com/cgi/content/full/330/7482/95-a] ]
The same birth injuries that can occur in vaginal breech birth may rarely occur in caesarean breech delivery. A Caesarean breech delivery is still a breech delivery. However the soft tissues of the uterus and abdominal wall are more forgiving of breech delivery than the hard bony ring of the pelvis. If a caesarean is scheduled in advance (rather than waiting for the onset of labor) there is a risk of accidentally delivering the baby too early, so that the baby might have complications of prematurity. With proper prenatal care, including first trimester ultrasound, this is theoretically impossible, and is indeed almost unheard of. The mother's subsequent pregnancies will be riskier than they would be after a vaginal birth (uterine rupture). The presence of a uterine scar will be a risk factor for any subsequent pregnancies.
Asynclitic birth, another abnormal birth position
* Banks, Maggie. "Breech Birth Woman Wise". Birthspirit Books, 1998.
* Fraser, Diane and Cooper, Margaret (Eds). "Myles Textbook for Midwives", 14th edition. Churchill Livingstone, 2003.
* Frye, Anne. "Holistic Midwifery: A Comprehensive Textbook for Midwives in Homebirth Practice, Vol I, Care During Pregnancy". Labrys Press, 1995.
* Gabbe, Steven; Niebyl, Jennifer; and Simpson, Joe Leigh (Eds). O"bstetrics: Normal and Problem Pregnancies", 4th edition. Churchill Livingstone, 2002.
* Goer, Henci, "Obstetric Myths versus Research Realities", Bergin and Garvey, London, 1995,
*Oxorn, Harry. "Human Labor and Birth", 5th edition. Appleton & Lange, 1986.
* Vernon, David ed. "Having a Great Birth in Australia"
Australian College of Midwives, Canberra, 2005 ISBN 0-9751674-3-X
* Waites, Benna. "Breech Birth". Free Association Books, 2003.
* [http://www.breechbabies.com/pictures.htm Photographs showing vaginal births of a breech babies]
* [http://news.bbc.co.uk/1/hi/health/2031173.stm Breech birth controversies in Great Britain]
* [http://www.birthingway.com/footling_breech.htm Photographs showing vaginal birth of a footling breech baby assisted by a midwife]
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Look at other dictionaries:
breech birth — UK [ˈbriːtʃ ˌbɜː(r)θ] / US [ˈbrɪtʃ ˌbɜrθ] or breech delivery UK [ˈbriːtʃ dɪˌlɪvərɪ] / US [ˈbrɪtʃ dɪˌlɪvərɪ] noun [countable] Word forms breech birth : singular breech birth plural breech births a birth in which the baby s head does not come out… … English dictionary
breech birth — also breech de.livery n a birth in which the lower part of a baby s body comes out of its mother first … Dictionary of contemporary English
breech birth — [ britʃ ,bɜrθ ] or breech de|liv|er|y [ britʃ dı,lıvəri ] noun count a birth in which the baby s head does not come out first … Usage of the words and phrases in modern English
breech birth — ► NOUN ▪ a birth in which the baby s buttocks or feet are delivered first … English terms dictionary
breech birth — noun delivery of an infant whose feet or buttocks appear first • Syn: ↑breech delivery, ↑breech presentation • Hypernyms: ↑delivery, ↑obstetrical delivery • Hyponyms: ↑frank breech, ↑ … Useful english dictionary
Breech birth — Literally, delivery of the baby by the buttocks first, rather than the head as is usual. Breech birth is more likely to cause injury to the mother or the infant. In many cases a baby in the breech position can be “turned” before delivery using… … Medical dictionary
breech birth — also breech de.liv.e.ry noun (C) a birth in which the lower part of a baby s body comes out of its mother first … Longman dictionary of contemporary English
breech birth — /ˈbritʃ bɜθ/ (say breech berth) noun a birth in which the back parts, rather than the head, are first presented … Australian English dictionary
breech birth — noun see breech delivery … New Collegiate Dictionary
breech birth. — See breech delivery. * * * … Universalium