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Obstetrics & Gynecology 2002;99:1025-1030
© 2002 by The American College of Obstetricians and Gynecologists
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ORIGINAL RESEARCH

Extremely Preterm Vaginal Breech Delivery en Caul

Jane R. Richmond, MD, Lucie Morin, MD and Alice Benjamin, MD

From the Department of Obstetrics and Gynecology, McGill University, Women’s Pavilion, Royal Victoria Hospital, Montreal, Canada.

Address reprint requests to: Jane R. Richmond, MD, McGill University, Department of Obstetrics and Gynecology, Women’s Pavilion (F4.46), Royal Victoria Hospital, 687 Pine Avenue West, Montreal H3A 1A1, Canada; E-mail: jane.richmond{at}muhc.mcgill.ca.


   ABSTRACT
TOP
ABSTRACT
MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
OBJECTIVE: To describe an alternative method of vaginal birth to the conventional assisted delivery for extremely preterm breech infants within intact amnions, and to compare the immediate neonatal outcomes with those delivered by cesarean.

METHODS: Retrospective review of singleton breech deliveries under 26 weeks’ gestation after spontaneous labor with intact membranes. Nine "en caul" vaginal births after tocolysis and six cesarean deliveries performed for the sole indication of preterm labor were identified between 1996 and 2001.

RESULTS: The vaginal group’s mean gestation and cervical dilatation on admission were 23+6 weeks and 3.2 cm, respectively, and 24+6 weeks and 2.8 cm in the cesarean group. Vaginal delivery occurred an average of 4 days after admission and 1 day for cesarean delivery. Mean time interval between the first corticosteroid injection and delivery was greater in the vaginal group (90 versus 22 hours). Failure to start or complete a steroid course was more likely in the operative group (67% versus 11%). Mean birth weights were comparable. Five-minute Apgar scores and cord pHs were 6 and 7.41, respectively, for vaginal births, and 5.5 and 7.32 after cesarean deliveries. Fifty-five percent of vaginally delivered infants had a 5-minute Apgar score less than 7, with 22% of the whole group dying during the first week of life. This compared with 66% and 50%, respectively, for cesarean infants. Of the survivors, average age at discharge was 121 days for both groups.

CONCLUSION: Vaginal birth can be effected in extremely preterm breech pregnancies with intact membranes by adopting the "en caul" delivery method.

After the publication of the Term Breech Trial results, the mode of delivery for persistent breech infants at term is no longer in dispute.1 This international multicenter randomized controlled trial (RCT) confirmed that a planned cesarean delivery is safer for the fetus than a planned vaginal delivery. There were no differences between the two groups in terms of maternal mortality or serious maternal morbidity. However, the optimal mode of delivery of extremely preterm singleton breech infants remains a topic of debate. At the margins of viability, where neonatal prognosis can be poor, difficult management decisions regarding the most favorable route of delivery have to be made.2 Although many papers have been published claiming that delivery by cesarean reduces the neonatal morbidity and mortality rates,3,4 others point out that such a policy leads to iatrogenic preterm delivery and possible serious maternal morbidity.5 The latter often leaves mothers with the future handicap of a vertical uterine scar, in return for a borderline viable infant.

However, most printed data are observational and retrospective, with statistical analyses only describing a trend, from which conclusions cannot be satisfactorily drawn.6,7 Other RCTs have been attempted, but have largely failed because of the problems with recruitment of patients.8,9 Thus, the debate between elective cesarean delivery and vaginal delivery with selective operative birth continues. The aim of this study is to present an alternative to the conventional "assisted breech" delivery, which has a similar immediate neonatal outcome to operative delivery.


   MATERIALS AND METHODS
TOP
ABSTRACT
 MATERIALS AND METHODS
RESULTS
 DISCUSSION
 REFERENCES
 
Recent practice at Royal Victoria Hospital, Montreal, Canada, has been to perform "en caul" vaginal breech deliveries in cases where spontaneous labor with intact membranes has occurred at gestations less than 26 weeks, in the absence of significant vaginal bleeding or nonreassuring fetal heart rate patterns. Tocolysis is used to reduce the uterine activity and diminish the maternal urge to push, even when delivery is inevitable. The mother is advised to adopt the Trendelenburg position to minimize the effect of gravitational forces on the bulging membranes. The pressure exerted by the intact sac allows passive dilatation of the cervix. The tocolytic agent is discontinued when the fetal presenting part reaches the perineum. Subsequently, the mother is allowed a few minutes of active pushing, during which the infant is expelled, encased within the intact pregnancy sac.

A review of extremely preterm singleton breech deliveries at this institution between April 1996 and March 2001 was undertaken. Only those resulting from spontaneous premature labor before 26 weeks’ gestation were studied. Pregnancies with preterm rupture of membranes before delivery were excluded. Both maternal and neonatal medical records were identified from the hospital’s database. The information extracted related to maternal age and parity, reason for and gestation at admission, cervical dilatation at first examination, corticosteroid and tocolytic administration, labor, gestation at birth, method of delivery, immediate neonatal outcome measures (Apgar score and venous cord pH), and the infants’ subsequent stay in and discharge from the neonatal intensive care unit. Dating of pregnancies was based on the last menstrual period, unless the discrepancy between the expected date of delivery derived from the first ultrasound scan at 18–20 weeks differed from that calculated from the last menstrual period by more than 7 days. In such cases, the expected date of delivery as predicted by ultrasonography was used. The outcomes of infants delivered vaginally with intact membranes were compared with those delivered by cesarean. Statistical analysis included descriptive techniques only.


   RESULTS
TOP
ABSTRACT
 MATERIALS AND METHODS
 RESULTS
DISCUSSION
 REFERENCES
 
There were 17,012 deliveries in this institution between April 1, 1996, and March 31, 2001, including 148 preterm (less than 37 weeks’ gestation) singleton breech births. Of these, 32 singletons presenting by the breech were delivered at a gestation less than 26 weeks. Nine cases of singleton breech fetuses, which had been delivered vaginally with intact membranes after tocolytic treatment, were identified. Six cesarean deliveries were reviewed: the sole indication for operation being a singleton breech less than 26 weeks’ gestation in spontaneous labor. The remaining singleton breeches born at less than 26 weeks either had preterm rupture of membranes or delivery precipitated by a significant antepartum hemorrhage, poor fetal well-being, or severe maternal disease. None of the reviewed cases of singleton breech infants in extreme preterm labor with intact membranes, who were intended for delivery by the vaginal "en caul" technique, experienced rupturing of the membranes during labor.

Group-specific maternal demographic data are presented in Table 1Go. Tables 2Go and 3Go show the antenatal and delivery details of individual cases in the vaginal and cesarean delivery groups. The mean gestation on admission was 23+6 weeks (range 22+1–25+2) and cervical dilatation 3.2 cm (range 2–4) in the vaginal delivery group, and 24+6 weeks (range 24+3–25+2) and 2.8 cm (range 1–5), respectively, in the cesarean delivery group. Maternal corticosteroid administration routinely consisted of three doses of betamethasone (12 mg intramuscularly), at 12 hourly intervals. This policy was changed to two doses of 12 mg of betamethasone, 24 hours apart, in 1999. The average interval between the first injection and delivery was greater in the vaginal delivery group: 90 hours (range 4–163) compared with 22 hours (range 6–47) in the cesarean delivery group. Failure to either start or complete a steroid course before delivery was more likely in the operative group (67% versus 11%). In the cesarean delivery group, one woman received no steroid therapy, whereas three women received only one dose. This compared with one patient in the vaginal delivery group, who delivered 4 hours after the first injection was given.


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  		Table 1. Maternal Demographic Data According to Delivery
 

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  		Table 2. Antenatal and Delivery Data of the Vaginal Birth Subgroup
 

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  		Table 3. Antenatal and Delivery Data of the Cesarean Delivery Subgroup
 
Eight of the women who gave birth vaginally received magnesium sulphate, one of whom also had combination therapy with salbutamol. One patient was given salbutamol alone. The total amount of magnesium sulphate administered ranged from 14.0 to 209.5 g, and the interval between discontinuation of the drug and delivery was 0–115 minutes (mean 40.8 minutes). Two of these eight women experienced side effects in the form of chest pain and shortness of breath, resulting in a temporary discontinuation of the infusion. Five women in the cesarean delivery group received tocolytic therapy, with magnesium sulphate and salbutamol being used. However, a failure to inhibit uterine activity among these five patients resulted in the decision being made that operative delivery should be effected without allowing labor to continue.

The infants born vaginally after the method previously described were delivered an average of 4 days after admission (mean gestational age at delivery 24+3, range 22+6–25+6) compared with 1 day for the cesarean delivery group (mean 25+0, range 24+3–25+2). Three cesarean deliveries were performed through classic incisions. There were no cases of head entrapment experienced in either delivery subsets.

Tables 4Go and 5Go outline the neonatal data for individual cases. The average birth weight was 680 g (540–865 g) for the vaginal delivery group and 644 g (530–1025 g) for the cesarean delivery group. The median 5-minute Apgar score and mean cord pH were 6 (3–8) and 7.41 (7.26–7.49), respectively, for the vaginal births, compared with 5.5 (4–7) and 7.32 (7.16–7.40) for operative births. No infant in the vaginal delivery group had a cord pH less than 7.20, with one such value arising in the cesarean delivery group. Fifty-five percent of vaginally delivered infants had a 5-minute Apgar value less than 7, compared with 66% of infants delivered by cesarean. Two of the nine infants (22%) born vaginally died in the immediate neonatal period, and three of the six infants delivered by cesarean (50%) died within the first week of life. Of the seven survivors in the vaginal delivery group and three survivors in the cesarean delivery group, the average age at discharge from the neonatal intensive care unit was 121 days for both groups. All deaths resulted from problems of extreme prematurity, in particular, lung disease, intraventricular hemorrhage, and sepsis. There were no congenital anomalies in either the vaginal or operative delivery groups.


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  		Table 4. Neonatal Data of Infants Delivered Vaginally "en Caul"
 

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  		Table 5. Neonatal Data of Infants Delivered by Cesarean
 

   DISCUSSION
TOP
ABSTRACT
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
REFERENCES
 
The incidence of breech presentation is far more common among preterm fetuses than term infants, being 21% at 25–26 weeks’ gestation, compared with 3–4% at term.10 Observational studies comparing the outcome of births among this group of infants have usually found higher neonatal survival rates after cesarean delivery than vaginal delivery. However, infants born vaginally were more likely to be those who were considered too sick, too small, or of too low a gestational age to receive sufficient benefit from cesarean delivery. The advanced stage of labor and cervical dilatation at the time of admission to the birthing unit meant they were also more likely to have foregone the benefits of antenatal steroid administration, and be born in the general birthing ward, in the absence of a senior obstetrician, anesthetist, or neonatologist. However, vaginal breech delivery at our hospital is a carefully coordinated procedure, carried out in the operating room, and attended by senior members of staff from the obstetric, neonatal, and anesthetic teams. Although different senior obstetricians deliver these infants, a team of two perinatologists is always consulted before delivery. A lack of care at such a critical point in life for an extremely premature infant is thus negated.

This case series has shown that vaginal birth can be effected, without compromising the fetus, by adopting the "en caul" delivery method described above. Delay in rupturing the membranes until the infant has completely passed through the vagina avoids the risk of entrapment of the aftercoming head by an insufficiently dilated cervix.4 The "en caul" method protects the easily traumatized infant and guards against cord prolapse. Our retrospective review has not looked at long-term outcome measures in later childhood.

The tocolytic agent most often employed in this hospital is magnesium sulphate, given as an intravenous infusion.11,12 Steer and Petrie11 demonstrated that this was most effective at controlling premature labor when the cervix was less than 2 cm dilated at the start of therapy. Recently, a Cochrane Review concluded that there was insufficient evidence to show that magnesium maintenance therapy is effective in preventing preterm birth after an episode of threatened preterm labor.13 In the context of preterm vaginal breech delivery, it may, though, reduce the rate of progression sufficiently to allow slow dilatation of the cervix, with subsequent controlled delivery of the fetus within the intact amnion, and delayed enough for the delivery to occur within the steroid window. The use of this drug requires careful maternal monitoring, as overdose results in cardiopulmonary depression. It has a narrow therapeutic window and can rapidly reach toxic levels in the presence of poor renal function. Concerns have also been raised over the safety of magnesium sulphate to fetuses, as it readily crosses the placenta.14–16 After the immediate postdelivery period, there were no additional neonatal complications in the group we studied, which could be attributed to prenatal drug exposure. Unfortunately, neither umbilical cord nor serum magnesium levels taken in the first few hours of life were recorded in the majority of infants who had received magnesium sulphate transplacentally.

The use of tocolysis allows in utero transfers to a tertiary center with adequate neonatal intensive care unit facilities and maternal intramuscular corticosteroids to be administered antenatally. A meta-analysis of 18 randomized trials, involving over 3700 infants, has shown the drug’s maximal effect to be when the first dose-delivery interval is greater than 48 hours.17 Antenatal corticosteroid therapy is associated with a significant reduction in the incidence of respiratory distress syndrome and neonatal death and a substantial lowering of the risk of intraventricular hemorrhage.17,18 The effect on infants delivered less than 28 weeks’ gestation, however, was not statistically significant, but the small number of infants included in this subgroup makes reliable analysis difficult. From our results, cesarean delivery occurred earlier in the course of events than if the labor had been allowed to progress spontaneously. Thus, fewer corticosteroid injections were given, and the overall time elapsed from the first dose to delivery was markedly less.

One possible advantage of the use of tocolytic agents and a planned vaginal birth is that labor may in fact arrest and delivery occur at some time distant. Cesarean delivery may, therefore, lead to the potentially unnecessary early delivery of a small infant in the absence of other complicating factors. For infants born at the margins of viability, an extra 24 hours in utero is associated with a 2–3% improvement in survival.2 Although the mean gestation at admission of the vaginal delivery group was 7 days less than that of the cesarean delivery group, there was only a 4-day difference in mean gestational age at delivery.

Most observational evidence indicates that for a preterm infant with a breech presentation, cesarean delivery results in lower perinatal mortality than vaginal delivery.19 A more recent meta-analysis of six reported trials of all presentations of infants born at less than 37 weeks finds that there is little difference in fetal outcome by mode of delivery (odds ratio 0.32, 95% confidence interval 0.07, 1.36, for lower perinatal mortality with cesarean delivery) but an increase in maternal morbidity (odds ratio 6.18, 95% confidence interval 1.27, 30.14).8 This may be severe morbidity including hysterectomy after major hemorrhage, sepsis, and thrombosis. No trials were reviewed where eligibility criteria included gestations less than 26 weeks. There are no reliable data concerning the mode of delivery for the subgroup 23+0–26+0 weeks, and, thus, no evidence that a policy of elective cesarean delivery for cephalic or breech presentations confers neonatal benefit for these gestations.20

The lower uterine segment is poorly formed at such early gestations, often requiring a vertical incision for operative delivery of the fetus, as occurred with half of the women who underwent cesarean deliveries in our case series. Vaginal birth of extremely preterm fetuses avoids the need for classic cesarean deliveries and the commitment to repeat cesareans to avoid the risk of uterine rupture in subsequent pregnancies.21 In the short term, vertical incisions are associated with a higher incidence of morbidity than transverse scars. In addition, there is a significant chance of a fetal abnormality or neonatal death in breech infants born so late in the second trimester. The mother’s health may, therefore, be compromised without achieving delivery of a viable infant. A risk-benefit equation must be carefully evaluated for each delivery method, based on the clinical facts of the individual case. The parents require detailed counseling, including discussion of both the obstetric and neonatal implications given by a senior member of the respective teams.

The majority of RCTs, which have been set up to examine the most favorable mode of delivery for preterm breech infants, have been closed earlier than intended because of the problems in recruiting sufficient women. Penn et al, in their multicenter RCT involving 26 hospitals in England, stopped recruiting at 17 months.22 Only 13 women with a singleton breech fetus in spontaneous preterm labor between 26 and 32 completed weeks’ gestation had been recruited in that time. They cited three main reasons for the low recruitment: the mode of delivery that is widely believed to ensure the health of the preterm breech fetus may not be in the mother’s best interest; the timing of trial entry; and preterm breech labor is an uncommon event, occurring in about one in 200 pregnancies. Therefore, the number of eligible women in any individual center is small. They concluded that it is unlikely that there will ever be a successful RCT of modes of preterm breech deliveries. Even with a pool of 60,000 births per year across 11 perinatal centers in the United States, others have agreed that an RCT to examine the optimal method of delivery for 24–28 weeks’ fetuses presenting by the breech was not feasible in a reasonable time span.23

In conclusion, the method of vaginal delivery "en caul" may be considered as an apparently safe alternative to conventional assisted delivery or cesarean delivery for extremely preterm infants in the breech presentation with intact membranes in whom there is a reassuring fetal heart pattern and in the absence of significant ante-partum hemorrhage. Selective use of operative delivery is appropriate, if clear clinical indications arise. Low-dose (or recently stopped) tocolysis allows the passive dilatation of the cervix and gradual descent and expulsion through the perineum of the infant within the intact sac. Complete delivery is usually achieved by one to two last minute maternal pushing efforts. To further justify the use of this alternative delivery technique, a prospective cohort study of all women presenting with a singleton breech with intact membranes in extremely preterm labor is indicated, with the intention of delivering them all "en caul."


   Footnotes
 
The source of this study was Women’s Pavilion, Royal Victoria Hospital, Montreal, Canada.

PII S0029-7844(02)02037-9

Received November 8, 2001. Received in revised form February 28, 2002. Accepted March 14, 2002.


   REFERENCES
TOP
ABSTRACT
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
1. Hannah ME, Hannah WJ, Hewson SA, Hodnett ED, Saigal S, Willan AR, et al. Planned caesarean section versus planned vaginal birth for breech presentation at term: A randomised multicentre trial. Lancet 2000;356: 1375–83.[Medline]

2. Morrison JJ, Rennie JM. Clinical, scientific and ethical aspects of fetal and neonatal care at extremely preterm periods of gestation. Br J Obstet Gynaecol 1997;104: 1341–50.[Medline]

3. Bowes WA, Taylor ES, O’Brien M, Bowes C. Breech delivery: Evaluation of the method of delivery on perinatal results and maternal morbidity. Am J Obstet Gynecol 1979;135:965–73.[Medline]

4. Bodmer B, Benjamin A, McLean FH, Usher RH. Has use of cesarean section reduced the risks of delivery in the preterm breech presentation? Am J Obstet Gynecol 1986; 154:244–50.[Medline]

5. Cox C, Kendall AC, Hommers M. Changed prognosis of breech-presenting low birthweight infants. Br J Obstet Gynaecol 1982;89:881–6.[Medline]

6. Westgren LM, Songster G, Paul RH. Preterm breech delivery: Another retrospective study. Obstet Gynecol 1985;66:481–4.[Abstract/Free Full Text]

7. Bennebroek Gravenhorst J, Schreuder AM, Veen S, Brand R, Verloove-Vanhorick SP, Verweij RA, et al. Breech delivery in the very preterm and very low birthweight infants in the Netherlands. Br J Obstet Gynaecol 1993;100: 411–5.[Medline]

8. Grant A, Penn ZJ, Steer P. Elective or selective delivery of the small baby? A systematic review of the controlled trial. Br J Obstet Gynaecol 1996;103:1197–200.[Medline]

9. Thornton JG, Lilford RJ. Preterm breech babies and randomised trials of rare conditions. Br J Obstet Gynaecol 1996;103:611–3.[Medline]

10. Hickok DE, Gordon DC, Milberg JA, Williams MA, Daling JR. The frequency of breech presentation by gestational age at birth: A large population-based study. Am J Obstet Gynecol 1992;166:851–2.[Medline]

11. Steer CM, Petrie RH. A comparison of magnesium sulfate and alcohol for the prevention of premature labor. Am J Obstet Gynecol 1977;129:1–4.[Medline]

12. Petrie RH. Tocolysis using magnesium sulfate. Semin Perinatol 1981;5:256–73.

13. Crowther CA, Moore V. Magnesium for preventing preterm birth after threatened preterm labour (Cochrane Review). In: The Cochrane Library, Issue 1. Oxford, UK: Update Software, 2001.

14. Mittendorf R, Covet R, Bowman J, Khoshnood B, Lee K-S, Siegier M. Is tocolytic magnesium sulphate associated with increased paediatric mortality? Lancet 1997;350: 1517–8.[Medline]

15. Riaz M, Porat R, Brodsky NL, Hurt H. The effects of maternal magnesium sulfate treatment on newborns: A prospective controlled study. J Perinatol 1998;18:449–54.[Medline]

16. Grether JK, Hoogstrate J, Selvin S, Nelson KB. Magnesium sulfate tocolysis and risk of neonatal death. Am J Obstet Gynecol 1998;178:1–6.[Medline]

17. Crowley P. Prophylactic corticosteroids for preterm delivery (Cochrane Review). In: The Cochrane Library, Issue 1. Oxford, UK: Update Software, 1999.

18. Liggins GC, Howie RN. A controlled trial of antepartum glucocorticoid treatment for prevention of the respiratory distress syndrome in premature infants. Paediatrics 1972; 50:515–25.[Abstract/Free Full Text]

19. Narayan H, Taylor DJ. The role of caesarean section in the delivery of the very preterm infant. Br J Obstet Gynaecol 1994;101:936–8.[Medline]

20. Grant A, Glazener CMA. Elective versus selective caesarean section for the delivery of the small baby (Cochrane Review). In: The Cochrane Library, Issue 1. Oxford, UK: Update Software, 2001.

21. Halperin ME, Moore DC, Hannah WJ. Classical versus low-segment transverse incision for preterm caesarean section: Maternal complications and outcome of subsequent pregnancies. Br J Obstet Gynaecol 1988;95:990–6.[Medline]

22. Penn ZJ, Steer PJ, Grant A. A multicentre randomised controlled trial comparing elective and selective caesarean section for the delivery of the preterm breech infant. Br J Obstet Gynaecol 1996;103:684–9.[Medline]

23. Eller DP, VanDorsten JP. Route of delivery for the breech presentation: A conundrum. Am J Obstet Gynecol 1995; 173:393–6.[Medline]





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