Description of the condition

Approximately 3% to 4% of all pregnant women who reach full term will have a fetus in breech presentation. This may be caused by an underlying fetal or maternal abnormality, or could be an apparently chance occurrence, or related to an otherwise benign variant such as cornual placental position. In the latter instance, breech presentation places a healthy fetus and mother at increased risk of a complicated vaginal delivery or caesarean section.

Breech delivery, whether vaginally or by caesarean section, has a higher incidence of poor perinatal outcomes than cephalic birth. For example, the incidence of minor childhood handicap following breech presentation has been found to be high (19.4%) and similar for those delivered following trial of labour and those following an elective caesarean section (Danielian 1996).

The majority of women with a breech presenting baby would prefer a vaginal birth although most would choose caesarean section if there is a medical indication (Gamble 2000; Geary 1997; Hildingsson 2002; Turnbull 1999). For the singleton fetus in breech presentation, caesarean section has been shown to be safer for the fetus than vaginal birth in many settings (Hofmeyr 2005), although a large prospective study suggested that vaginal breech delivery may be safe under certain conditions with experienced practitioners (Goffinet 2006).

The risks associated with caesarean section are low, however caesarean section is not without maternal risk and in developed countries remains the largest contributing factor to the incidence of maternal mortality and morbidity following childbirth (Minkoff 2003). A Cochrane review of planned caesarean section versus planned vaginal delivery for breech pregnancy at term, reported that even though 45% of women in the planned vaginal delivery group were delivered by caesarean section, planned caesarean section was associated with an increase in maternal morbidity (risk ratio (RR) 1.29, 95% confidence interval (CI) 1.03 to 1.61) (Hofmeyr 2003). Furthermore, although the overall risk is very small, recent estimates of the incidence of mortality associated with elective caesarean section were nearly tripled compared to vaginal birth (Cooper 2002; Hall 1999). In addition to the increase in immediate morbidity following caesarean section, intra‐abdominal adhesions may occur after caesarean section resulting in subsequent infertility (LaSala 1987). The presence of the uterine scar puts future pregnancies at increased risk of complications such as ectopic pregnancy, placenta previa, accreta and abruption, and uterine rupture (Dashe 2002; Gilliam 2002; Lydon‐Rochelle 2001; Minkoff 2003). A further deterrent to caesarean section is that the procedure requires the expertise of an obstetrician or other health worker with surgical training, and limits the role for low‐risk obstetrical care providers such as midwives and family practitioners. A review of strategies to reduce caesarean section rates identified external cephalic version (ECV) as the only clinical intervention with demonstrated Level 1 evidence for reducing primary caesarean section rates overall (Walker 2002).

Description of the intervention

Considering the complications that can arise from breech delivery, it is not surprising that, over the years, the possibility of manipulating the baby from the breech to the cephalic presentation has intrigued obstetric caregivers. ECV is a procedure in which the baby is manipulated by pressure through the mother's abdominal wall into a cephalic (head‐down) position.

ECV before term (usually before 34 weeks' gestation) came into routine obstetric practice on the basis of the self‐evident immediate effectiveness of the procedure as well as reassuring results from several non‐randomised trials, and in spite of the negative results of the only randomised trial reported prior to 1980 (Brosset 1956). The popularity of ECV before term waned after the mid‐1970s, partly because of reports of a substantial perinatal mortality associated with the procedure (Bradley‐Watson 1975), and the increasing perception of caesarean section as a safer option than ECV or breech delivery.

Prior to the mid‐1970s, ECV was usually attempted before term because of the belief that the procedure would seldom be successful at term. Subsequent studies showed that with the use of tocolysis (medication to relax the uterus), ECV could be achieved in a substantial proportion of women with breech presentation at term. ECV at term differs in many fundamental ways from that performed before term. These include the fact that the fetus is mature and may be delivered more readily in the event of complications, and that spontaneous versions without ECV attempt, or reversion after successful ECV, are less common at term. ECV before term is therefore evaluated as a separate procedure (see 'External cephalic version for breech presentation before term' (Hutton 2006)). The current review includes studies in which the intention was to include pregnant women at or near term (i.e. from 36 weeks' gestation).

External cephalic version at term has been shown to be feasible in two small uncontrolled trials in women with previous caesarean section (Flamm 1991; Schachter 1994), and in two in women in labour (Ferguson 1985; Fortunato 1988). El‐Muzaini 2008a and El‐Muzaini 2008b are abstract reports of prospective controlled studies of ECV in labour and with previous caesarean section respectively, with results in favour of ECV, but it is not clear whether these studies were randomised. To our knowledge, no randomised trials of these interventions have been reported.

Several authors have investigated which factors are associated with an increased chance of successful external cephalic version (Boucher 2003; Fortunato 1988; Guyer 2001; Lau 1997; Le Bret 2004). Factors which have been found to predict failure of ECV attempt include engagement of the presenting part, difficulty in palpating the fetal head and a tense uterus on palpation (Lau 1997), and increased amniotic fluid volume (Boucher 2003). However, a prediction model based on clinical parameters was found to be insufficiently accurate to be useful in predicting the outcome of ECV attempts (Chan 2004).

The majority of women prefer vaginal birth over caesarean birth (Hildingsson 2002). As ECV is the primary intervention to achieve a vaginal delivery when the baby is in breech presentation, it would seem logical that women would be highly motivated to try it. The preferences of women with breech presentation regarding their care appear to have changed over the past couple of decades, and vary by location. In an Israeli study in 1995, 54% were willing to consider ECV and 65% preferred planned caesarean section if the breech presentation persisted, compared with 24% and 97% respectively in 2001 (Yogev 2002). In an Australian study in 2001, 39% of women attending antenatal clinic would choose ECV if needed, and 22% were undecided (Raynes‐Greenow 2004). In another Australian study, Nassar 2007 evaluated a decision aid for women with breech presentation at term. The decision aid was not intended to increase or decrease intervention rates, but rather aim to support informed decision‐making that is consistent with personal values. Seventy‐four per cent of women who were randomised to receive the decision aid expressed an intention to have ECV if needed, while 66% of women who received normal care would choose ECV. A higher proportion of women who received the additional information reported that they had enough information to make a decision (95.7%, compared with 73.6%, at first follow‐up). The women who received the decision aid experienced lower decisional conflict, increased knowledge, and greater satisfaction with their decision. Murray‐Davis 2012 reported that women participating in a trial comparing the timing of ECV preferred the procedure to be carried out at 34 to 36 weeks' gestation rather than after 37 weeks, as it was perceived to have physiological and practical advantages. However, their sample is likely to have over‐estimated preferences for early ECV as that option was only available to trial participants.

Complications reported following ECV at term include fracture of the baby's femur (Papp 2004), prolonged tachycardia (rapid heartbeat) of the baby (Nzewi 1999), sinusoidal baby's heart rate pattern (a fluctuating pattern sometimes indicating compromise) (Ferber 1999), and fetal‐maternal haemorrhage (bleeding from the baby's to the mother's circulation in the placenta) (Shankar 2004). The rate of caesarean section during labour has been found to be greater following successful ECV than in spontaneous cephalic presentation: 20% versus 6.3%, RR 3.2 (Ben‐Haroush 2002); 27.6% versus 12.5%, RR 2.04; 95% CI 1.43 to 2.91 (Chan 2004b); odds ratio 2.04 for nulliparous women, 4.30 for multiparous (Vezina 2004). This is not surprising, given that women with persistent breech presentation in the first instance are a high‐risk group. Cord blood gases at delivery were no different (Chan 2004c).

However, series of cases have reported very low complication rates with ECV (Boucher 2003; Impey 1999; Impey 2005; Tong 2012). A review of 44 studies of ECV (7377 participants) from 1990 to 2002 found the most frequently reported complication to be transient abnormal baby's heart rate patterns (5.7%). Less frequent complications were persisting pathological baby's heart rate patterns (0.37%); vaginal bleeding (0.47%); placental abruption (0.12%); emergency caesarean section (0.43%); and perinatal mortality (0.16%) (Collaris 2004). Because of the risk of allo‐immunisation, anti‐D prophylaxis is recommended for non‐sensitised D‐negative women following ECV attempts (Fung Kee Fung 2003).

Contra‐indications to ECV include: multiple pregnancy, severe abnormality, unsatisfactory condition or death of the baby, caesarean section necessary irrespective of the presentation (e.g. major placenta praevia), and ruptured membranes. Relative contraindications include previous caesarean section, poor growth of the baby, and bleeding from the uterus.

The question of whether ECV might increase the risk of mother‐to‐child transmission of viral infections such as HIV is important and, in the absence of direct evidence, we have reviewed the relevant biological evidence and concluded that, unlike fetal‐maternal transfusion (bleeding from the baby's to the mother's circulation in the placenta), maternal‐fetal transfusion is extremely rare, and unlikely to be precipitated by ECV (Holmes 2004). It is also reassuring that in a randomised trial of fundal pressure to expel the baby during caesarean section, no evidence of maternal‐fetal transfusion was found (Owens 2003).

Several authors have reported success rates for ECV at term in routine clinical practice in the region of 40% to 50%: 53% (Hughes 1997); 39% (Williams 1999); 55% (Guyer 2001); 45% (Devendra 2002); 43% (Lojacono 2003); 51% (Skupski 2003); 42% to 65% (depending on amniotic fluid volume (Boucher 2003)); and 51% (Le Bret 2004).

Readers are referred to previous reviews of the topic (Hofmeyr 1989; Hofmeyr 1991; Hofmeyr 1992; Hofmeyr 1993; Zhang 1993). See also related Cochrane systematic reviews: 'External cephalic version for breech presentation before term', 'Cephalic version by postural management for breech presentation' and 'Interventions for helping to turn term breech babies to head first presentation when using external cephalic version.' (Hutton 2006; Hofmeyr 2000; Cluver 2012).

Why it is important to do this review

There is a higher risk of complications when delivering a baby presenting in the breech rather than in the cephalic position. Caesarean section appears to be safer for the baby, but presents a higher level of maternal morbidity. Achieving a cephalic vaginal delivery by successfully rotating the baby in utero therefore, potentially offers a way to reduce the caesarean section rate, and improve perinatal and maternal outcomes. It may be of particular importance in resource‐poor situations in which women may be unable to reach health services during labour, and caesarean sections are unavailable or unsafe (Hofmeyr 2004).