Breech Delivery

Breech presentation occurs when the fetus presents to the birth canal with buttocks or feet first. This presentation may create a mechanical problem in delivery of the fetus.

Singleton breech delivery

Breech delivery has become increasingly rare both in the United States and globally. In recent decades, the perceived relative safety of cesarean delivery has made this route of delivery increasingly common for breech presentation.

This trend was accelerated by a 2000 study by Hannah et al. ^[2]  This randomized study of 2083 patients compared planned cesarean delivery (1041 patients) with planned vaginal birth (1042 patients) for breech presentation. The authors concluded, "Planned caesarean section is better than planned vaginal birth for the term fetus in the breech presentation; serious maternal complications are similar between the groups." ^[2] This conclusion was made on the basis of a significantly lower fetal and neonatal morbidity and mortality in the planned cesarean group. Of course, it is understandable that this conclusion would dampen any remaining enthusiasm for vaginal breech delivery. Giving strength to this trend was the 2001 ACOG Committee on Obstetric Practice recommendation, which stated that "planned vaginal delivery of a singleton breech is no longer appropriate." ^[3]

Those who are proponents of vaginal delivery point out that since this was a randomized controlled trial, none of the accepted selection criteria for safe vaginal breech delivery were employed. Thus, decisions based on extant prognostic factors were not applied to inclusion of patients in the planned vaginal breech delivery arm. In other words, no well-known selection criteria were applied to ascertain the safety of vaginal breech delivery. Had those been applied, results may have been more favorable.

In a follow-up study, the same group who conducted the 2000 study found that "the risk of death or neurodevelopmental delay was no different in the planned cesarean delivery group compared with the planned vaginal delivery group." ^[4] Other studies have, as well, tempered the findings of the initial study described above.

ACOG recommends that external cephalic version be offered as an alternative to a planned cesarean section for a patient who has a term singleton breech fetus, wishes to have a planned vaginal delivery of a vertex-presenting fetus, and has no contraindications. ACOG also advises that external cephalic version be attempted only in settings where cesarean delivery services are available. ^{[1, 5]}

Twin breech delivery

In twins with a cephalic leading twin and a breech second twin, it is reasonable to expect that the dynamics of the delivery of the second twin in breech presentation would differ significantly from that of a singleton breech presentation. Indeed, a Cochrane database review that looked at 2864 combined cases concluded: "There is insufficient evidence to support the routine use of planned caesarean section for term twin pregnancy with leading cephalic presentation, except in the context of further randomised trials." ^[6]

A review by Aviram et al concluded that breech extraction performed by an experienced obstetrician offers a greater likelihood of successful vaginal delivery of the noncephalic second twin than does external cephalic version. ^[7]

The buttocks and feet of the fetus do not provide an effective wedge to dilate the cervix so that the after-coming head might get trapped during delivery. Also, the umbilical cord may prolapse due to the increased space between the presenting buttocks and feet without the benefit of a fetal part well applied to the cervix .

The 3 types of breech presentation are as follows:

• Frank (65%): Hips of the fetus are flexed, and knees are extended.

• Complete (10%): The hips and knees of the fetus are flexed.

• Incomplete (25%): The feet or knees of the fetus are the lowermost presenting part.

  • Single footling: One of the lower extremities is lowermost.

  • Double footling: Both of the lower extremities are lowermost.

Risk factors for breech presentation at delivery include the following:

• Preterm gestational age: Prior to the onset of labor, the fetus typically turns into a cephalic presentation. If labor occurs abruptly or unexpectedly (eg, following trauma), the fetus may not have yet shifted position.

• Increased maternal parity may cause stretching or laxity of the uterus, predisposing the fetus to breech deliveries.

• Multiple fetuses: As a result of limited space in the uterus, fetuses may position themselves head to foot.

• Hydramnios, ie, too much amniotic fluid, may allow the fetus too much movement.

• Oligohydramnios, ie, too little amniotic fluid, may impede the final shift of the fetus into a cephalic presentation. ^[8]

• Placenta previa, ie, placental implantation over the cervical os, allows the fetus too much space for movement within the uterus.

• Hydrocephalus, ie, enlarged head in the fetus, makes it more difficult for the fetus to make shift to cephalic presentation prior to the onset of labor.

• Previous breech deliveries may increase likelihood of another one secondary to an anatomical anomaly.

  • Uterine anomalies include uterine scarring from a previous cesarean section, bicornuate uterus, or a septate uterus.

  • Pelvic tumors may impede fetal movement and trap the fetus in a breech presentation.

United States data

Incidence is correlated to gestational age (see the Table below). However, the overall frequency is 3-4% at delivery. ^[9]

Table. Gestational age and frequency of breech birth (Open Table in a new window)

International data

The international incidence has been reported at 3-4%. ^[2]

Age-related demographics

Older maternal age is a consideration. ^[10]  A Finnish study found that advanced maternal age (≥35 years) is a risk factor for breech presentation in moderate to late preterm pregnancies (32-36 weeks’ gestation) as well as in term pregnancies. ^[11]

Fetal and maternal morbidity and mortality increase with breech delivery. Fetus and infant mortality increases to 9%, compared with 3% in cephalic presentations.

A rise in the number of cesarean deliveries increases the maternal morbidity and mortality (eg, wound infection, aspiration, anesthesia risk), especially with emergency delivery.

A Danish study found that nulliparous women with a singleton breech presentation who had a planned vaginal delivery were at significantly higher risk for postoperative complications, compared with women who had a planned cesarean delivery, owing to the likelihood of conversion to an emergency cesarean section, which occurred in over 69% of planned vaginal deliveries. ^[12]

The average Apgar score, especially at 1 minute, is lower. Congenital abnormalities increase to 6%, compared with 2.4% in infants with cephalic presentations.

Factors for increased adverse fetal outcome include the following ^[9] :

• Older mothers

• Footling presentation

• Hyperextended fetal head

• Birth weight less than 2500 g or greater than 4000 g

• Prolonged labor

• Nonexperienced clinician

Morbidity/mortality

Various complications are associated with a breech presentation in labor. This may be due to the underlying etiology of the breech presentation, such as fetal anomalies or polyhydramnios. In addition, complications can occur as a result of umbilical cord compression due to the unusual presentation to the maternal pelvis.

The inexperienced provider when faced with a slowing fetal heart rate from cord compression  is more likely to apply traction on the fetus prematurely, increasing the risk of birth trauma and nuchal arms. Nuchal arms lead to complications with delivery of the head by increasing the diameter required for delivery.

The incidence of prolapsed umbilical cord depends on the type of breech presentation, as follows:

• Footling – 17% incidence

• Complete – 5% incidence

• Frank – 0.5% incidence

Umbilical cord abnormalities can occur. Cord length may be reduced, and, in footling breeches, there is an increased risk of the cord coiling around a leg of the fetus.

Complications

Traumatic mortality to the fetus is 12 times more likely. Intracranial fetal hemorrhage is the most common injury in breech delivery. In decreasing order of frequency, the spinal cord, liver, adrenals, and spleen also are injured.

Patient education is an essential part of all medical practice. This is especially true for breech delivery.

Early prenatal care can identify patients at risk for breech delivery.