In the United States, VBD has largely become relegated to the history books, as study after study has demonstrated increased risks of neonatal morbidity and mortality associated with the procedure.^1–3 Many of the earlier studies were retrospective in nature or were small prospective ones without the power to look comprehensively at VBD safety.^4–10 The question of safety was finally answered with a large, prospective randomized control trial (RCT) that demonstrated higher rates of neonatal morbidity and mortality with planned VBD compared to planned C-section.¹ This study, as well as follow-up research on the same population, addressed both maternal and newborn outcomes and demonstrated no negative impact on the mother and only a negative impact on the newborn’s immediate morbidity and mortality.^1,11–13

With this rapid decline in VBD, skilled practitioners have become less available to perform these deliveries due to a lack of training of new providers and knowledgeable ones retiring.¹ In spite of this attrition, there are often times when, unexpectedly, a patient who has a fetus in breech presentation presents in advanced labor, and the only option is to perform a VBD. Another scenario is the woman who knows that she is in breech position and refuses a C-section. In these cases, the obstetric (OB) provider must be able to safely deliver the breech baby vaginally.

The American College of Obstetrics and Gynecology (ACOG) recognizes that, despite the small but real risk of perinatal morbidity and mortality associated with VBD, some patients may still desire and seek out providers who will perform routine VBD. If those providers want to perform VBDs, they must set up hospital-based protocols utilizing best practices in order to optimize outcomes and provide adequate informed consent.¹⁴ In addition, the maneuvers involved in a VBD are very similar to those done when delivering a breech fetus by C-section, and understanding these maneuvers with both routes of delivery is critical.

Up until the late 1970s, VBD was the route of delivery chosen by most women who presented breech late in gestation. Breech presentation late in the third trimester represents about 3% to 5% of all pregnancies, but it is associated with a higher rate of congenital malformations or syndromes compared to their vertex counterparts, which may have caused the fetus to be breech in the first place.^15–18 Often, a VBD newborn who was not “normal” led the parents to look for someone to blame, and the route of delivery was often thought to be the cause of the condition. The medical and legal issues connected with VBD cases led many practitioners to avoid performing them if possible. This chapter presents the evidence for the increase in morbidity and mortality associated with VBD, describes the VBD maneuvers themselves, and discusses the pitfalls to avoid with VBD, how to obtain consent from a patient who wants to undergo a VBD, and when to consider performing a VBD and when not to.

CATEGORIES

The various types of breech presentation are demonstrated in Figure 59-1. These types mostly relate to the position of the lower extremities in relation to the fetal breech (or butt). When one or both extremities are below the level of the presenting breech, it is designated a footling breech, also called incomplete (Fig. 59-1A). When both fetal thighs and lower extremities are flexed (Fig. 59-1B), the fetus is designated to be sitting cross-legged, and this is a complete breech. When the fetal thighs are flexed and the lower legs are extended (Fig. 59-1C), it is designated a frank breech. This last type of breech has the lowest risk of delivery complications, and it is often required to be present if a VBD is to be considered.

NEWBORN RISKS ASSOCIATED WITH VAGINAL BREECH DELIVERY

One major concern with any VBD is the risk of head entrapment. The human fetal head circumference is larger than the abdominal circumference until about 36 weeks gestation, after which the abdominal circumference becomes larger. With vertex presentation, the largest fetal body part acts to open the cervix during labor; and normally, once the head is delivered, the body quickly follows. With VBD, the fetal body may not open the cervix sufficiently to allow the more ridged fetal head to pass through the partially open cervix. With the frank breech presentation, the body-leg wedge normally is sufficient to open the cervix enough to allow the trailing fetal head to pass through. An exception to this is when the fetal head is hyperflexed and presents with the largest cranial diameter (known as the occipito-mental diameter), which is very difficult to deliver; and there is a significant risk of spinal cord injury when the head presents this way.^15,16 With footling or complete breech, the cervix may not be opened enough to allow the head to deliver. Overall, the risk of head dystocia is 5% to 9% as presented in the literature.^10,15

A second risk of VBD is that of umbilical cord prolapse, where the umbilical cord will present in the vagina before the baby delivers, a situation that represents a true obstetrical emergency. If the umbilical cord is compressed and no umbilical blood is getting to the fetus, the newborn must be delivered within minutes or else permanent damage could occur due to birth asphyxia. The chance of umbilical cord prolapse is higher based on the type of breech: frank breech 1%, complete breech 4%, and incomplete breech 14%.^10,15,19

VBD has been associated with an increase in neonatal morbidity and mortality, including birth trauma, brachial plexus injury, cerebral palsy, and other injuries.^2,3,15,18 Breech presentation has been found to be associated with genetic abnormalities (e.g. trisomy 21, or Down syndrome) as well as other syndromes that present with polyhydramnios or abnormal neuro muscular development.^13,18 When a breech presentation is identified late in the third trimester, it is critical that a focused ultrasound has been performed (or gets done at that time) to rule out congenital malformation or another possible syndrome/condition. Certainly, a trial of VBD should not be performed until a pathologic cause of the late breech presentation is ruled out. If there was a level 2 ultrasound at 20 weeks, with normal anatomy and genetic screening, a follow-up ultrasound should be performed to document growth (and the estimated fetal weight) and to check for frank or complete breech presentation and for head and neck flextion.

PRETERM VAGINAL BREECH DELIVERY

With the very preterm fetal head being significantly larger than the rest of the fetal body, the risk of head entrapment is much higher in the preterm infant who delivers vaginally. In addition, the preterm fetus is much more likely to be breech (and footling breech at that, which represents the highest risk of birth injury). A large, retrospective study of preterm breech deliveries found a significant increase in perinatal morbidity and mortality when preterm VBD were compared to breech C-section.³ Clearly, women with a preterm breech delivery should be counseled on the risks of a preterm VBD.

THE TERM BREECH TRIAL

The gold-standard study, a RCT, was performed by Hanna et al (2000), who performed an international, multicentered study that included skilled practitioners in VBD and included both nulliparous and multiparous women.¹ The study took place in 121 centers in 26 countries in both developed and underdeveloped countries around the world, with 1041 patients randomized to planned C-section and 1042 to planned VBD.¹ When examined by intention to treat, there was a significantly lower risk of neonatal mortality and severe neonatal morbidity in the planned C-section group [risk ratio (RR) 0.33; 95% confidence interval (CI) 0.19, 0.56 P < 0.0001] than in the planned VBD group.¹ When developed countries with an already low perinatal mortality rate (PMR), such as the United States, were examined, the risk was even higher, suggesting that the VBD would affect overall PMR to a greater extent.

Multiple follow-up studies of both the impact of C-section on mothers and long-term follow-up on newborns support the finding that the only real impact for an increase in morbidity and mortality is at the time of delivery.^1,11–13 The Hannah et al study led many providers around the world to stop performing VBD electively, and today planned VBD is very rarely performed. Other retrospective studies demonstrated similar findings for large populations for term and preterm VBD.^2,3

MATERNAL RISKS

An early prospective RCT by Collea, Chein, and Quilligan (1980) found that VBD was as safe as C-section in terms of the risk to mother and baby.⁹ Their study had small numbers (only in the 200s) and included an inflated maternal risk, as all mothers with a Hct < 30% were transfused, and this maternal morbidity was the main complication in the C-section group. Today, we rarely transfuse someone at that level of anemia.

With the significant increased C-section rate over the past 30 years, we have become aware of other complications of C-section, including abnormal placentation conditions such as placenta accreta, increta, and percreta.²⁰ While once rarely seen, they have become almost routine for high-risk obstetrical units and involve a multidisciplinary team of surgeons and intensive care unit (ICU) intensivists, with transfusion of multiple units of blood products. In spite of developing these teams, the maternal mortality rate in these cases is as high as 1%.¹⁹ With the Term Breech Trial, there was no significant increase in maternal morbidity or mortality at 2 years of follow-up, suggesting that C-section was safe in cases of planned breech C-section.^1,11–13 This study, however, was neither designed nor powered to study long-term complications such as placenta implantation abnormalities.

DEMOGRAPHICS

Parity is often considered in patients who present for VBD, as the second and later deliveries will have a much shorter second stage, and the breech almost delivers itself. The nulliparous patient certainly can undergo a trial of VBD, but most providers are less likely to consider attempting it due to the much longer second stage and risk of difficult delivery.^2,3 Any patient with an underlying medical condition (diabetes, morbid obesity, etc.) that puts her at risk of having a macrosomic fetus or sets her up for shoulder dystocia in the vertex presentation should probably avoid a VBD. Box 59-1 lists the factors that should be present if a VBD is going to be considered.

PAST OBSTETRICAL HISTORY

As described previously, the multiparous patient is a much better candidate for a VBD except where the fetus is much larger than her prior deliveries. One of the strongest indications for a successful VBD is a prior VBD.²¹ Another ideal candidate is the patient who has undergone one or more vertex vaginal deliveries with average to large babies and who now presents with a breech fetus who is on the smaller side. As birthweight generally increases with increasing parity, one must be careful to estimate fetal weight as best one can to avoid attempting a macrosomic breech delivery.

EMERGENCY AS OPPOSED TO PLANNED VAGINAL BREECH DELIVERY

The patient who wants to undergo a planned VBD usually finds a provider who will help them achieve this goal. As described earlier, these providers are becoming more difficult to find as experienced providers retire and new providers are not trained in performing VBD. What is more likely to happen is the women who presents in advanced labor who did not know she was breech, or she decided to wait until labor was advanced in an effort to have a VBD. In these latter cases, the provider may barely have time to assess the patient before the breech presents on the perineum and effectively the only choice is to proceed with a VBD. In the case where the breech is on the perineum and there is insufficient time to rule out pathology, the provider must just proceed with the VBD, as no other option is available. If the breech has not engaged into the pelvis, about ‒1 to 0 station, or if the presenting breech is sufficiently high in the pelvis, there still should be time to perform a C-section. It is important to talk with the patient to see what their desires are, if known. However, if the patient was unaware of the breech presentation then a C-section should be performed in an urgent manner. Technically, a C-section could be performed after the breech has descended into the pelvis but while trying to take the patient to the operating room and administer anesthesia, the breech could deliver in this process. It is why the perineum should be monitored prior to administering a general anesthesia or rapid spinal. With the multiparous patient, there may not be enough time for a C-section, but in the case of a nulliparous patient, this is not usually the case.

MECHANICS OF NORMAL LABOR AND VAGINAL DELIVERY

With the lack of ability to learn how to perform a VBD in the pregnant patient, performing simulated VBD in the Simulation (Sim) laboratory is crucial.²² If a hospital decides to have a VBD protocol for those patients and providers who want to perform VBD, part of that protocol should include education in a Sim laboratory. Most medical schools and/or obstetric and gynecologic (OB/GYN) residency programs have available or participate in VBD simulations. These types of programs provide important technique and skills in dealing with VBD, and anyone who might have to perform a planned or emergency VBD should regularly participate in these types of simulations. Many of the maneuvers for the VBD described below are demonstrated in Figure 59-2. Two important factors when considering a VBD are to make sure that there is continuous fetal monitoring available and that the provider has skills in performing a VBD. The other factors were listed in Box 59-1, earlier in this chapter.