Alarab, May MD; Regan, Carmen MD; O'Connell, Michael P. MD; Keane, Declan P. MD; O'Herlihy, Colm MD; Foley, Michael E. MD
The management of breech presentation in term pregnancy is highly controversial. Management practice varies among different institutions, and even among different clinicians in the same institution. The decision to perform cesarean delivery is often based on personal experience or fear of litigation. A recent randomized multicenter trial recruited in 26 countries comparing planned cesarean versus planned vaginal birth concluded with a strong recommendation for cesarean delivery for term breech pregnancies in both developed and developing countries, based on perinatal outcome.1 The study indicated that planned cesarean delivery reduced perinatal mortality, late neonatal death, and serious neonatal morbidity by one third. Nevertheless, the interpretation of the results has been challenged with respect to the trial's clinical design, specifically because a minority of perinatal deaths were related to the mode of delivery, because it recruited from countries with widely varying underlying perinatal outcome, because the definitions of serious neonatal morbidity were loosely defined, and because some of the clinical practices employed were questionable.2,3
Cesarean delivery for breech presentation has been shown to increase both short- and long-term maternal morbidity and maternal mortality in both observational4–7 and randomized controlled studies, not least because it predisposes to further cesareans in subsequent pregnancies.8 Neonatal respiratory morbidity is also increased up to five-fold following elective cesarean delivery.9 A change to cesarean delivery for all breech presentations in institutions currently offering a trial of vaginal delivery (with a 50% vaginal delivery rate) would double the cesarean rate attributable to breech from 2% to 4% of all term deliveries, with an inevitable incremental effect on the repeat cesarean rate. Even when a policy of routine prelabor cesarean delivery is adopted for all term infants presenting by the breech, a significant number of women will still present at a stage of labor too advanced for cesarean, while others will request a trial of vaginal delivery.10 Although external cephalic version reduces noncephalic birth by 60%11 and is strongly recommended as a safe alternative to breech delivery, term pregnancies after successful external version remain at higher risk of intrapartum cesarean.12
At the National Maternity Hospital, a standardized approach to the management of a breech presentation has been adopted for the past decade. Strict selection criteria are applied before a trial of vaginal breech delivery is undertaken and a fixed management practice, including avoidance of induction and oxytocin augmentation and avoidance of prolonged active second stage, is observed during breech labor, with a low threshold for intrapartum cesarean. We have analyzed the results of this protocol with respect to maternal and perinatal outcome for the period immediately preceding publication of the multicenter randomized trial. Our aim was to assess the safety of carefully selected and supervised vaginal breech delivery in a single institution with a low underlying perinatal mortality rate.
MATERIALS AND METHODS
At the National Maternity Hospital details of all deliveries, including elective and emergency cesarean deliveries are recorded on a computer database immediately after delivery, including data on parity, gestational age, birth weight, duration of first and second stages, Apgar scores, cord blood pH, admission to special care neonatal unit, and fetal/neonatal outcome. Later events, including neonatal death and neurological morbidity, are collated in the Hospital's annual clinical report. Until 2000, the ethnicity of the Hospital's obstetric population was stable and 98% Caucasian; patient management did not alter with respect to ethnicity. This computerized data set was used to examine the perinatal and obstetric outcomes of all women attending with a singleton breech presentation at 37 weeks of gestation or more during the 3.5-year period January 1997 to June 2000.
Patients found to have a breech presentation were referred to a dedicated breech clinic, generally at 37 weeks of gestation, where a structured ultrasound examination was performed, documenting placental site, estimated fetal weight, amniotic fluid quantitation, type of breech, fetal attitude, and fetal morphology. External cephalic version was offered, with informed consent, if the estimated fetal weight, amniotic fluid volume, placental site, and fetal morphology were normal. During the study period the success rate of external cephalic version was 50% in multiparas and 32% in nulliparous women.
If breech presentation persisted or recurred, patients were offered a trial of vaginal delivery if the following criteria were fulfilled: 1) estimated fetal weight of 2,500–3,800 g13; 2) deepest amniotic fluid pool 30 mm or more; 3) normal fetal morphology and normal placental location; 4) absence of hyperextension of the fetal head (an angle exceeding 90°); and 5) flexed (complete) or extended (frank) breech presentation. Management of fetal anomaly depended on the type of malformation identified. Elective prelabor cesarean was advised, based on the following fetal indications; estimated fetal weight more than 3,800 g, footling breech, hyperextension of the fetal head or when fetal compromise was suspected (oligohydramnios or intrauterine growth restriction). Maternal indications for elective cesarean included maternal preference, previous cesarean, significant preeclampsia and placenta previa. Antepartum pelvimetry was not used. Consent concerning mode of delivery was obtained according to the Hospital protocol and maternal preference.
Induction of labor was not practiced with breech presentation. Elective prelabor cesareans were scheduled after 39 weeks of gestation or, if otherwise assigned, if labor had not ensued after 41 weeks. Women allocated to prelabor cesarean who labored spontaneously were delivered by cesarean on admission. On admission in spontaneous labor, vaginal examination was performed to confirm the diagnosis of labor, the type of breech presentation and to exclude cord presentation. When the diagnosis of labor was confirmed, amniotomy was performed to augment labor, provided the presenting part was fixed in the pelvis and continuous electronic fetal heart rate monitoring was initiated. Subsequent progress was assessed vaginally every 2 hours. Cervical dilatation at a rate of 1 cm/h or more was deemed acceptable. In the second stage, 1 hour was allowed if required for adequate descent of the breech to the pelvic floor; delivery of the fetus was completed within 1 hour of active pushing for nulliparas and within 30 minutes for multiparas.
Oxytocin was not used to augment labor in either the first or second stage; failure to progress in labor was considered an indication for intrapartum cesarean. If fetal distress was suspected, cesarean delivery was effected without fetal blood sampling; meconium staining of amniotic fluid alone was not deemed an indication for cesarean delivery. Epidural administration was based on maternal request. An experienced obstetrician (senior resident with at least 4 years experience or consultant) conducted all vaginal breech deliveries, and a pediatrician was also in attendance. Breech delivery was spontaneous with active maternal pushing, but no intervention by the attending obstetrician, until the fetus was delivered to the level of the umbilicus. Lovset's maneuver was used to deliver the shoulders if required, and episiotomy was performed routinely. Delivery of the head was then controlled with Mauriceau-Smellie-Veit maneuver or with Neville-Barnes obstetric forceps, depending on the obstetrician's preference. Cord blood acid base analysis was performed at the discretion of the attending obstetrician or if the 1-minute Apgar score was less than 7.
Data were analyzed by using unpaired t test, Fisher exact test, and analysis of variance, as appropriate; P values less than 0.05 were considered significant.
During the 42-month study period, 641 patients presented with singleton breech presentation at term, of whom 374 (58%) were nulliparas and 267 (42%) were multiparas; 343 patients (54%) underwent elective prelabor cesarean delivery, according to our institutional selection criteria, and 298 (46%) progressed to a trial of vaginal delivery. Specific obstetric indications for elective cesarean delivery were present in 192 (56%) cases; birthweight more than 3,800 g in 98, gestation more than 41 weeks in 51, previous cesarean in 18, preeclampsia in 10, suspected fetal compromise in 12, hemolytic disease in 2, and placenta previa in 1 case. Nonspecific indications, such as maternal or obstetricians preference, pertained in 151 cases.
Of 298 patients who progressed to a trial of vaginal delivery, 146 (49% of the total) delivered vaginally and 152 (51%) were delivered by intrapartum cesarean (Figure 1); 13 (8.6%) intrapartum cesareans were performed in the second stage of labor. One hundred forty-three of the intrapartum cesareans (94%) were performed for failure to progress in labor and 7 (4.6%) for suspected fetal distress; all 7 babies had Apgar scores of 9 at 1 minute. Of a total of 158 nulliparas and 140 multiparas who labored, 58 (37%) and 88 (63%), respectively (P < .001), delivered vaginally (Figure 2). Epidural analgesia was used in 159 (53%) labors, 96(61%) nulliparas and 63 (45%) multiparas; 82 (56%) women with epidural analgesia delivered vaginally.
Group-specific analyses comparing the prelabor cesarean and planned vaginal delivery cohorts and frequency of birth weights exceeding 3,800 g are summarized in Tables 1 and 2. Significant preponderance of larger infants was allocated to prelabor cesarean and was selected for intrapartum cesarean delivery, particularly among nulliparas.
The mean durations of the first and second stages of labor for nulliparas who delivered vaginally were 4.4 hours (range 0.5–11), and 24 minutes (5–75), respectively, and for multiparas were 3 hours (0.2–11), and 13 minutes, (10–45), respectively. Nine (6%) women, 2 nulliparas and 7 multiparas, presented in labor at full dilatation, and all delivered vaginally. The durations of the first stage of labor in patients who were delivered by intrapartum cesarean was 3.8 hours (0.5–9) for nulliparas and 2.4 hours (0.5–8) for multiparas. Two intrapartum cesareans were performed because of cord prolapse, an incidence of 0.7%.
Venous cord blood pH was measured in 68 (46%) of 146 of infants who were delivered vaginally; no value was less than 7.1, and pH was between 7.1 and 7.2 in 11 (7.6%) samples. Two infants (0.7%) had Apgar scores of less than 7 at 5 minutes (cord pH 7.12 and 7.1, respectively), both in the vaginally delivered group and were admitted to the Special Care Baby Unit; both were discharged within 24 hours, and both were neurologically normal at 6 weeks of age. Seven infants developed transient respiratory difficulties, 3 after prelabor cesareans, 2 after intrapartum cesareans, and 2 after vaginal deliveries. There were no intrapartum or neonatal deaths in normally formed infants and no neonate exhibited abnormal neurological behavior in either the vaginally or cesarean delivered cohorts; the 95% confidence interval for risk of death associated with vaginal delivery was 0%, 2.53%. No cases of major soft tissue, neurological, or skeletal trauma were identified in either cesarean or vaginally delivered breech infants. Infants were followed up routinely until 6 weeks postpartum. Three perinatal deaths occurred, all due to lethal malformation, comprising a neonatal death due to renal agenesis and 2 stillbirths due to Trisomy 18 and neural tube defect, respectively; all three infants were delivered vaginally.
These results show that with appropriate prelabor and intrapartum selection combined with the mandatory attendance of an experienced obstetrician to conduct delivery, the outcome of vaginal breech delivery was uncomplicated and that one half of our patients who undertook a trial of labor delivered vaginally. Our findings confirm the satisfactory results reported in a similar, well selected series.3,14–18 Our criteria adopted to select larger fetuses for cesarean proved reasonably discriminant in that a significantly smaller proportion of infants weighing 3,800 g or more presented in labor, and in turn twice as many larger infants were delivered by intrapartum cesarean than delivered vaginally.
In contrast to the definite selection criteria for elective cesarean cited in other breech studies, protocols for the management of term breech in labor are generally less well defined. In this respect, we would commend the application of our guidelines relating to limitation of the duration of the first and second stages of labor, and avoiding induction and oxytocin augmentation of slow progress. Our limits on the duration of labor are based on the averages for nulliparas and multiparas with cephalic presentations in our institution, and overall our results for labor duration fell within these parameters. In a large series of unselected patients, we have previously reported a mean duration of nulliparous labor of 6 hours, with 37% delivery within 4 hours of admission in labor; among multiparas 78% delivered within 2 hours of admission.19 Malpresentations including breech have always been considered a contraindication to oxytocin augmentation in our unit.20
The prerequisite of an experienced obstetrician to ensure safe conduct of safe breech delivery (no less than of cesarean) has been emphasized in many reports. Indeed further analysis of the results of the Term Breech Trial have identified the importance of an experienced accoucheur in attendance.21 The overall vaginal delivery rate following trial of labor in our series, at 49%, may have been influenced by our high incidence of epidural analgesia22 but was comparable with the 56% reported by Hannah et al1 This was despite our much more stringent criteria for intrapartum management, specifically exclusion of induction, oxytocin augmentation, and active second stage exceeding 60 minutes. Not surprisingly, these factors have been shown to have significantly increased the risk of adverse fetal outcome in the term breech trial cohort.21 What is not discernible from those data is what the perinatal outcome would have been in those women randomized to vaginal delivery were these risk factors excluded.
Comparable with other breech series from countries with similarly low background mortality rates,23,24 there were no normally formed perinatal deaths in our consecutive study group and little neonatal morbidity. In fact, the incidence of low Apgar scores and low cord pH values was similar to that of the planned cesarean cohort in the Term Breech trial and almost identical to the rate among electronically monitored low-risk cephalic deliveries at our institution.25 It is noteworthy that perinatal mortality results in the Term Breech trial did not differ significantly in participating centers in countries with low baseline rates, despite the fact that randomization was not stratified according to underlying national mortality rates.
We present our findings not as an argument that breech presentation is without risk but to suggest that with active involvement of experienced obstetricians and applying appropriate management protocols, vaginal breech delivery can achieve comparable safety for the infant with spontaneous cephalic birth. It should be borne in mind that only 23% of our total breech patients and 49% of those who labored eventually delivered vaginally, with significantly more multiparas, compared with nulliparas, achieving vaginal delivery. Our data are of assistance in accurately counseling women with breech presentation at term and in advising a trial of labor and vaginal delivery if that is the maternal preference; they may help to balance the relative safety of selected breech delivery for the infant against the potential maternal risks of cesarean delivery. Nevertheless, institutions where vaginal breech delivery is conducted should continue to audit their outcomes, not least in an era when appropriately supervised experience for obstetricians in this mode of delivery is inevitably becoming more difficult to acquire.
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