Breech Presentation and External Cephalic Version

Candace Cooley was among the contributors to a published study of external cephalic version, the procedure in which a clinician turns a breech fetus by hand toward a head down position, and that study examined how often the procedure succeeds and what risks accompany it. Breech presentation is the situation the procedure answers. In the closing weeks of pregnancy a fetus usually settles with the head lowest, which obstetricians call a vertex presentation; the American College of Obstetricians and Gynecologists defines breech as the alternative in which the buttocks, the feet or both are positioned to emerge first, and puts it at 3 to 4 percent of births at full term.⁴

The position has an ordinary origin. Breech is very common early in pregnancy, when the fetus is small and has room to tumble, and patient guidance from the Royal College of Obstetricians and Gynaecologists explains that by 36 to 37 weeks most babies have turned head first on their own. That guidance names three shapes the position can take: frank or extended breech, the most frequent, with the thighs drawn up and the feet near the ears; flexed breech, with the knees bent and the feet beside the bottom; and footling breech, with one or both feet below the bottom.⁶ Often the reason a particular fetus stays put is simply chance. The same guidance lists features that make turning harder, including a low lying placenta, too much or too little amniotic fluid and more than one baby.⁶ A HealthDay item carried by ABC News adds that babies born early are more likely to be breech than babies born at term, and that twins and other multiples carry a higher chance as well.² Contemporary OB/GYN lists growths that change the shape of the uterus and several previous pregnancies among the linked conditions.⁸

A clinician can often tell how a fetus is lying by pressing gently on the abdomen to locate the head, back and buttocks, and ACOG notes that an ultrasound or a pelvic examination can confirm what the hands suggest.⁴ How sound waves build that picture is covered in obstetric ultrasound.

External cephalic version turns the fetus by hand

The version is a manual maneuver performed from outside the body. ACOG describes a clinician, sometimes two, applying firm pressure to the abdomen so that the fetus rolls head down, with ultrasound often used to guide the turn and the fetal heart rate checked before and afterward. The attempt stops right away if a problem arises, and it is usually done near a delivery room so that a cesarean birth can follow quickly if one becomes necessary.⁴

Figure

How an external cephalic version attempt runs

1. 01
   ConfirmAn ultrasound scan confirms the breech position, and the mother's pulse and blood pressure are checked.
2. 02
   MonitorThe fetal heart rate is checked with monitoring before the attempt begins.
3. 03
   RelaxMedication may be given to relax the muscle of the uterus, which improves the odds of turning.
4. 04
   TurnFirm pressure from one or two clinicians' hands on the abdomen rolls the fetus toward head down, sometimes guided by ultrasound.
5. 05
   RecheckThe scan and the heart rate check are repeated, and the attempt stops at once if a problem appears.

ACOG suggests it may be offered once a breech pregnancy passes 36 weeks.⁴ The Royal College adds that a medicine relaxing the uterine muscle improves the chances of turning, and that the procedure can still be tried up to the early stages of labor.⁶ One expectant mother, writing for NPR in 2011, recorded how it was explained to her: one hand near the head, the other near the buttocks, the baby rolled while its heart was watched, with no promise of success and some discomfort for the mother.¹ The NHS likewise calls it safe but a bit uncomfortable.⁷

Not every pregnancy is a candidate. ACOG lists more than one fetus, concerns about the health of the fetus, certain abnormalities of the reproductive organs, a placenta in the wrong place and a placenta that has begun to separate as reasons the turn will not be tried, though a previous cesarean birth does not by itself rule it out.⁴ The Royal College adds recent vaginal bleeding, an abnormal heart rate tracing and waters that have already broken.⁶

The results are mixed but steady. ACOG reports that more than half of attempts succeed, that the turn grows harder as the fetus gets bigger, and that possible complications include early rupture of the membranes, changes in the fetal heart rate, placental separation and early labor.⁴ The Royal College puts success at about one in two, higher for women who have given birth vaginally before, and says fewer than 5 in 100 turned babies flip back; immediately afterward there is roughly a 1 in 200 chance of an urgent cesarean because of placental bleeding or heart rate changes.⁶ Medscape reported in 2018 on a review of 4,117 term breech pregnancies at one academic hospital in Chicago. Only about a third had a version attempt and 40 percent of attempts worked, yet 79 percent of the turned babies were born vaginally, and the combined measure of serious newborn problems did not differ from expectant management, at 2.9 against 2.5 percent. Fear, a preference for a planned cesarean and incomplete information were cited as reasons women decline.⁹

Figure

One hospital's decade of breech pregnancies at term

of the women had a version attempt

30.7%

of attempts turned the fetus

40.3%

of successfully turned babies were born vaginally

79%

Home remedies have a long following. The NPR writer tried an exercise ball, a bag of frozen vegetables held over the baby’s head and music played low on the belly.¹ A mother profiled by NBC News did handstands in a pool before her doctor turned the baby manually, after which she gave birth vaginally on her due date.³ The Royal College is plain that no scientific evidence shows lying or sitting in particular positions helps, although some evidence supports moxibustion, the burning of a Chinese herb called mugwort, at 33 to 35 weeks.⁶

Birth when the breech position persists

If the fetus stays breech, the remaining choices are a planned cesarean birth or a planned vaginal breech birth. ACOG notes that most breech babies are now born by planned cesarean, and explains why a vaginal breech birth carries more risk: the body emerges first and may not open the cervix enough for the head, which can become caught against the pelvic bones, and the umbilical cord can slip down ahead of the baby and be compressed.⁴ The Royal College leaflet frames the trade plainly. Research has found a planned cesarean safer for the baby, while a vaginal breech birth carries a small added risk of the baby dying around the time of delivery, though its short term complications do not appear to have lasting effects; and about 4 in 10 women who plan a vaginal breech birth end up needing a cesarean anyway.⁶

Figure

Two planned routes when the breech position persists

	Planned cesarean birth	Planned vaginal breech birth
For the baby	Shown by research to be the safer route	A small added risk of death around the time of delivery
For the mother	Slightly more risk than a vaginal birth	The least risk when it succeeds
Ends in cesarean anyway	Not applicable	About 4 in 10 women who plan it
Setting	A planned operation	A trained breech team in a hospital ready for an emergency cesarean

A cesarean has costs of its own. ACOG lists infection, bleeding and injury to nearby organs, along with uterine rupture and placental complications in later pregnancies, risks that grow with each operation.⁴ In the NBC News report, a Stanford obstetrician observed that doctors were seeing more placental complications after earlier cesareans and that more than 90 percent of later births follow a first cesarean by the same route.³ The NHS lists situations in which a vaginal breech birth is advised against: a footling breech, a baby much larger or smaller than average, a sharply tilted neck, a low lying placenta and preeclampsia.⁷ Where a version fits in the wider sequence of late pregnancy visits is set out in the prenatal care schedule. Which route suits any one pregnancy is a decision for the woman and her own clinician to reach together.

The debate has a long memory. The 2011 Contemporary OB/GYN overview cited an ACOG technical bulletin from 1986 and observed that many training programs had stopped teaching vaginal breech delivery, even as up to 17 percent of breech babies were still born that way.⁸ In 2018 ACOG’s committee opinion on breech delivery, replacing a version from 2006, made the same observation about vanishing skills and urged clinicians to offer a version attempt where cesarean services are close at hand.⁵ The Royal College leaflet of 2017, which grew out of an edition first issued in February 2008, gave a version success rate of about 50 percent, close to the more than half that ACOG cites today.⁶ Three decades on, the questions set down in 1986 are still being asked in nearly the same words.