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Breech delivery: Why the dilemma?
Breech delivery: Why the dilemma? Stephen A. Myers, D.O., and Norbert Gleicher, M.D. Chicago, Illinois A critical review of selected studies of breech delivery is presented with special attention to the statistical analysis of outcome for low birth weight and term breech delivery. Analysis of the data fails to support the routine use of cesarean birth for all cases of breech delivery except for those with hyperextension of the head. The implication of these findings is discussed. (AM J OssTET GYNECOL 1986;155:6-1 0.)
Key words: Breech delivery, cesarean section
Cesarean delivery rates continue to increase in spite of National Institutes of Health consensus report recommendations to the contrary. The abdominal route of delivery is often chosen even when clear, convincing data fail to demonstrate any advantage over the vaginal route, with repeat cesarean sections representing the most significant example. Because breech delivery accounts for only 10% to 15% of all cesarean sections (3% of all deliveries) and because many authors advocate routine cesarean section for breech delivery, not much attention has been focused on this cesarean delivery indication. It is the purpose of this review to critically analyze the obstetric literature in order to answer the question of whether cesarean section for breech presentation results in better obstetric outcome when compared with vaginal delivery. An all-encompassing review of the breech literature is neither relevant to the above question nor within the scope of this communication. A more complete review of all breech data has recently been published.' Several key issues and their key references will, however, be discussed in more detail. Review of published data
Outcome comparisons of breech delivery and delivery in cephalic presentation, which may vary in magnitude, are nonetheless uniform in their results. For most of the important end points, infants born in breech presentation do worse than those in cephalic presentation. This comparison has been summarized by Seeds and Cefalo 2 (Table I). With this adverse outcome in mind, increasing use of cesarean section for breech delivery has occurred on the basis of the assumption that abdominal delivery would improve out-
From the Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, M aunt Sinai Hospital Medical Center and Rush Medical College. Supported by the Foundation of Reproductive Medicine, Chicago, IL 60610. Reprint requests: Stephen A. Myers, D. 0., Division of Maternal-Fetal Medicine, Mount Sinai Ho.1pital Medical Center, California Ave. at 15th St., Chicago, lL 60608.
6
Table I. Risks associated with breech · presentation Fetal risk
Approximate incidence
Prematurity Major anomalies Birth trauma Cord prolapse Intrapartum asphyxia Spinal cord injuries and deflexion Hyperextension of head Arrest of aftercoming head
16%-33% 6%-18% 13 times normal risk 5-20 times normal risk 3-8 times normal risk 21%
5% 8.8%
Modified from Seeds and Cefalo. 2
come. Major factors to be considered in analysis of this issue are: frank versus nonfrank breech presentation, the use of Piper's forceps, preterm breech delivery, and term breech delivery. Frank versus nonfrank breech
The observation has been made that nonfrank breech presentation is accompanied by increased perinatal mortality." This observation has been used tojustify the suggestion that patients with infants with nonfrank breech presentation not be allowed to labor. However, two important variables that affect outcome compound the analysis of nonfrank breech presentations-birth weight and cord prolapse. Goldenberg and Nelson 4 have demonstrated that the proportion of breech deliveries that are nonfrank increases as birth weight decreases. They reviewed the records of 141 patients with breech presentation who were delivered vaginally. Their findings reveal, in infants weighing <2000 gm, that 66% of all breech presentations are nonfrank, whereas only 33% are frank. Consequently, data comparing frank and nonfrank presentations alone may include differences in birth weight distribution that will also affect outcome and survival. A second factor may also compound outcome analysis comparing frank and nonfrank breech presentation. Nonfrank breech presentations are associated with significantly more instances of cord prolapse. 2
Breech delivery
Volume 156 Number I
7
Table II. The low birth weight breech Survival ratio of vaginal to cesarean deliveries Birth weight Years of study
Ratio of vaginal to cesarean deliveries
1970-1975
61/16
35/75
0
0
I 970-1975
47/18
0
0
0
1970-1977
II 9/32
35/75
0
0
Duenhoelter et al. 9 Mann and Gallant 15
I 972-1977
44/44 279/157
45/100 0
0 0
0 0
Effer et al. 16
1973-1980
67/95
0
0
0
Gimovsky et al. 6
1980
25/44
0/67
0
0
Main et al. 11
I 977-1981
123/93
42/71
0
0
Author
Woods'
Karp et al. 3 Bowes et al.
8
1000-1499,1500-1999,2000-2499 gm gm gm
Unless outcome analysis includes adjustments for these two potential biases, incorrect conclusions may follow. Two studies that do not have the above biases have failed to demonstrate any difference in outcome for frank and nonfrank breech delivery. Woods,' in a retrospective review of 73 breech deliveries, failed to show any difference in outcome of frank or nonfrank breech delivery. He also failed to show any benefit of cesarean section for either group. Similarly, Gimovsky et al., 6 in a prospective randomized study, failed to demonstrate a beneficial effect of cesarean section. In that study all infants with nonfrank breech presentation were randomized to either abdominal or vaginal delivery. The groups were comparable in birth weight and gestational age. No differences in the rate of mortality or trauma were demonstrated. In spite of these data, cesarean section continues to be recommended for nonfrank breech presentations. Piper's forceps
Milner7 has demonstrated that application of Piper's forceps to the aftercoming head will reduce neonatal mortality by one half in all birth weight groups. He observed a neonatal mortality of 162/1000 when Piper's forceps were not used, compared with 28/1000 when Piper's forceps were used. Moreover, this difference was still present when the data were analyzed by specific birth weight groups, for instance, for 1000 to 1499 gm birth weights, 22% mortality with forceps and 4 7% mortality without forceps. 7 Although these mortality figures are not directly comparable to more recent information, no published data refute Milner's conclu-
Comments
Head entrapment X 7 in vaginal group. Respiratory distress syndrome cause of mortality in >50% 17% prolapsed cord in nonfrank breech Includes 500-1500 gm birth weight since no difference with 500-999 gm documented 60% of deaths before 1974 No difference in 500-999 gm group. No difference in Apgar scores No difference in 500-999 gm group Similar for 500-999 gm group. Mortality only <1300 gm Includes 67 deliveries of 750999 gm
sion. Despite this observation, reports of vaginal breech delivery continue without either discussion of the use of Piper's forceps or tabulation of frequency of their usage. It can only be stressed that the use of Piper's forceps be more routinely applied and reported. Low birth weight breech
Perhaps the most controversial data regarding the effect of route of delivery on outcome are in the low birth weight breech group. Although fetopelvic disproportion does not occur, the possibility of head entrapment may be theoretically increased on the basis of the relatively larger head in a premature infant. Moreover, many authorities believe that premature infants are more susceptible to "trauma" during vaginal delivery. The eight most prominent studies covering this issue are summarized in Table II. Included in the table are the years in which the studies were performed, the total number of infants studied, and survivals in each of three birth weight groups. Inspection of these data reveals that no author was ever able to demonstrate a benefit of cesarean section in birth weights above 1500 gm, compatible with 30 to 31 weeks' gestational age, yet routine cesarean section generally is advocated for premature breech infants. Very low birth weight breech
Data for the very low birth weight breech infant deserve further scrutiny. Studies of Woods,' Bowes et al.,S and Duenhoelter et a!." share a common flaw. In the early 1970s, the viability of infants weighing < 1500 gm was clearly questioned. These three studies included
8
Myers and Gleicher
January 1987 Am J Obstet Gynecol
Table III. Mortality in very low birth weight breech deliveries (n = 37)
Table V. Recommendations for breech delivery Factors favoring vaginal delivery
Significance
500-999 gm 1000-1499 gm Mortality(%)
12 3 93
Sample <1000 gm (%)
80
9 13 33 41
p < 0.05 (authors' data) p < 0.05 (our calculation)
Modified from Gimovsky et al. 6
Table IV. Mortality in very low birth weight breech deliveries (n = 37) Vaginal
750-999 gm 1000-1249 gm 1250-1499 gm No. of deaths/ Total No. Sample < 1000 gm (%)
45/52 19/40 7/31 711123 (58%) 43
Cesarean section
9115 12/46 6/32 27/93 (29%) 16
Significance
NS NS NS p < 0.05 p < 0.05 (our calculation)
Modified from Main et a!. 11
patients who were delivered vaginally because they were thought in fact to carry previable infants. As an almost self-fulfilling prophecy, many of these infants subsequently died. Although cesarean section was occasionally carried out for maternal indications, it was usually only performed if the fetus was considered viable. Since the prognosis of viability was not prospectively controlled for in the management decisions of these three studies, the studies have to be considered of questionable validity and can be useful for comparative purposes only. Two of the later studies (Table II) warrant further discussion. Gimovsky and PauJI" reported a considerable benefit of cesarean sections in the very low birth weight group (Table III). However, 40% of deaths in their group delivered vaginally occurred in infants weighing <750 gm. Were these infants considered viable at Los Angeles County Hospital in 1980, or would they be considered as such even today? Moreover, the confounding effect of birth weight distribution differences between vaginal and abdominal groups was not considered. A significantly higher percentage of infants < 1000 gm occurred in the vaginal group compared with the abdominal group (80% vaginal versus 41% abdominal; p < 0.05, our calculation). Surely the effect of birth weight on survival cannot be ignored. An identical error was made by Main et a!." (see Table IV).
Birth weight <4200 gm Adequate pelvis Good progress of labor Absence of hyperextension of fetal head Factors favoring cesarean section
Birth weight >4200 gm Borderline pelvis Poor progress of labor (particularly descent) with adequate contractions Fetal distress Hyperextension of the fetal head
Although they correctly noted that there was no significant difference in survival in any of the three birth weight groups between 750 and 1500 gm, they chose to add the three weight groups together to come to the extraordinary conclusion that the vaginal delivery group did worse. In doing so, they failed to note that by lumping all three groups together, the vaginal group birth weights were skewed to those <1000 gm (43% under 1000 gm in the vaginal group versus 16% under 1000 gm in the cesarean group; p < 0.05, our calculation). Once again the confounding effect of birth weight on survival was interpreted as an effect of the route of delivery. The most definitive data published to date on route of delivery for very low birth weight infants were recently presented by Kitchen et a!. 12 from Melbourne. Their work included data on 326 infants born at 24 to 28 weeks' gestation between 1977 and 1982. Included in this group were 117 breech deliveries. The work of the Melbourne group stands out from all other published data for three major reasons. First, a prospective determination was made that all infants in the study were viable and consequently no infant's management was prejudiced by the expectation that the infant would die. Second, statistical analysis was performed with the use of a stepwise logistic regression analysis that took into account 14 different obstetric variables that could affect survival, including route of delivery. Last, and most important, half of the study infants were evaluated at 2 years of age with neurological and developmental assessments. We know of no other study of very low birth weight breech deliveries that includes these three crucial elements. The route of delivery was not prospectively randomized in the Melbourne study. It was assumed that vaginal delivery was safe and cesarean section was reserved for obstetric indications such as fetal distress and maternal disease. Only 16% of breech deliveries were by cesarean section. The authors found no difference between the two groups in either immediate or long-term outcome. Those advocating routine abdominal delivery for the very low birth weight
Breech delivery 9
Volume 156 Number 1
breech have no comparable data in support of their recommendation. Term breech
Regarding term breech deliveries the two most significant studies for current obstetric practice are by CoHea et a!. 13 and Green et a!. 14 CoHea et a!. 13 studied the outcomes of 208 patients with frank breech presentation at term in a prospective study with patients randomized to either vaginal or abdominal delivery. The conclusion of the authors was that vaginal delivery of the term frank breech was acceptable, provided patients fulfilled the minimum criteria of their study protocol. 13 There was no apparent advantage of cesarean section for the neonate. As expected, maternal morbidity was significantly greater in the abdominal delivery group. A more provocative observation was made by Green et al. 14 in Montreal. When they retrospectively observed the outcome of 600 term breech deliveries during the period 1963 through 1973, they noted that birth trauma and birth asphyxia occurred in 18% of the deliveries. The cesarean section rate for that group was 22%. They reasoned that this incidence of birth trauma and birth asphyxia, which they considered unnecessarily high, could be reduced by the more liberal use of abdominal delivery. By 1978, they had been successful in increasing their cesarean section rate to 94% of all breech deliveries. Subsequent review of their data for 1978 and 1979 (n = 175) again indicated an incidence of birth trauma and birth asphyxia of 18%. This experience clearly demonstrates that the increase in cesarean section rate did not affect breech outcome. The experience factor
It has been suggested that because today's obstetricians have inadequate experience with vaginal breech delivery, abdominal delivery represents a more prudent choice for "young practitioners." We reject this notion for several reasons. First, ignorance about the technique of breech delivery can result in trauma in both vaginal and abdominal delivery. A fetus will thus not benefit from abdominal delivery if the delivery technique used is inappropriate. It is the profession's responsibility to provide training in breech delivery technique during the residency period. During this time a house officer has the opportunity to accumulate a concentrated, supervised experience, unmatched by any subsequent period of his or her professional life. The education of young physicians has to be the responsibility of senior obstetricians who have accumulated sufficient clinical experience in breech delivery to serve in a consulting capacity. Within such an educational framework, one could in fact foresee that these senior consultants will be available during
vaginal breech deliveries at their institutions. Patients could thus be assured that breech deliveries are performed by the most experienced obstetrician in the safest way for mother and infant. After all, inexperience should never be the reason for a surgical solution. Experience is usually available. Cost consideration
Cesarean section, compared with vaginal delivery, costs an additional $2700 per patient in hospital cost alone. Among 3.5 million deliveries per year in the United States, approximately 122,500 are in breech presentation. Currently, national cesarean section figures suggest that approximately 70% to 80% of all breech deliveries are performed by cesarean section. If the above-mentioned data from the Melbourne 14 and Montreal' 6 groups are representative and a 20% cesarean section rate can safely be applied, 50% to 60% of breech deliveries (60,000 to 70,000 deliveries per year) are at present subjected to unnecessary cesarean sections. The annual national hospital cost for unnecessary cesarean sections for breech presentation thus approaches $200,000,000 per annum. These cost calculations do not include added costs for physician services, etc. Improved neonatal outcome could justify such cost. As should be evident, from the above-presented data, however, no such benefit exists. Recommendation
On the basis of the review of obstetric literature, we suggest that previously held risk factors for vaginal delivery, such as nonfrank breech presentation, parity, and low or very low birth weight, are not associated with increased risk for birth trauma or birth asphyxia when vaginal delivery is compared with cesarean section. Patients presenting in labor with breech presentation must have the following: (1) ultrasound examination to exclude obvious anomalies, check placental localization, corroborate clinical estimate of fetal weight, and evaluate the angle between the cervical and thoracic spine; (2) clinical or x-ray pelvimetry if estimated fetal weight is >3500 gm or to corroborate hyperextension of the fetal head if ultrasound is unavailable or inadequate; (3) continuous electronic fetal monitoring; (4) adequate documentation of normal progress of labor. Should risk factors known to be associated with adverse outcome develop, cesarean delivery is to be used (see Table V). On the basis of the Montreal and Melbourne experience, 14 ' 16 the need for abdominal delivery should, however, not exceed 20% to 25% of all breech deliveries. Effective cesarean section monitoring programs for breech presentations therefore need to be developed. Such programs could include mandatory chart review and could be designed to tabulate which risk factors for vaginal breech delivery
10 Myers and Gleicher
have been documented on the chart. However, peer review can only be effective if a consensus develops in the professional's above-outlined guidelines. Most important, such an approach could be taken with confidence that no adverse effects on either mother or newborn infant would occur. REFERENCES I. Confino E, Gleicher N, Elrad H, Ismajovich B, David M. The breech dilemma. A review. Obstet Gynecol Surv 1985;40:330-6. 2. Seeds S, Cefalo R. Breech delivery. Clin Obstet Gynecol 1985;25: 145-56. 3. Karp LE, Doney JR, McCarthy T, Meis PJ, Hall M. The premature breech: trial of labor or cesarean section? Obstet Gynecol 1979;53:88-92. 4. Goldenberg RL, Nelson KG. The premature breech. AM j 0BSTET GYNECOL 1977;127:240-4. 5. Woods JR. Effect of low birth weight breech delivery on neonatal mortality. Obstet Gynecol 1979;53:735-40. 6. Gimovsky ML, Wallace RL, Shifrin BS, et a!. Randomized management of the nonfrank breech presentation at term: a preliminary report. AM j 0BSTET GYNECOL 1983; 146:34-40. 7. Milner RDG. Neonatal mortality of breech deliveries with and without forceps to the aftercoming head. Br J Obstet Gynaecol 1975;82:783-5. 8. Bowes WA Jr, Taylor ES, O'Brien M, Bowes C. Breech
January 1987 Am J Obstet Gynecol
9.
10. II. 12.
13. 14.
15. 16.
delivery: evaluation of the method of delivery on perinatal results and maternal morbidity. AM J OBSTET GYNECOL 1979; 135:965-70. Duenhoelter JH, Wells E, Reisch JS, et a!. A paired controlled study of vaginal and abdominal delivery of the low birth weight breech fetus. Obstet Gynecol 1979;54: 310-3. Gimovsky ML, Paul RH. Singleton breech presentation in labor: experience in 1980. AM j 0BSTET GYNECOL 1982; 143:733-9. Main DM, Main EK, Maurer MM. Cesarean section versus vaginal delivery for the breech fetus weighing less than 1500 grams. AMj 0BSTET GYNECOL 1983;146:580-4. Kitchen W, Ford GW, Doyle LW, eta!. Cesarean section or vaginal delivery at 24 to 28 weeks' gestation: comparison of survival and neonatal and two-year morbidity. Obstet Gynecoll985;66:149-57. ColleaJV, Chein C, Quilligan EJ. The randomized management of term frank breech presentation. A study of 208 cases. AMj 0BSTET GYNECOL 1980;137:235-42. Green JE, McLean F, Paul Smith L, eta!. Has an increased cesarean section rate for term breech deliveries reduced the incidence of birth asphyxia, trauma, and death? AM j 0BSTET GYNECOL 1982; 142:643-8. Mann L, GallantJM. Modern management of the breech delivery. AM j 0BSTET GYNECOL 1979;134:611-4. Effer B, Saigal S, Rand C, eta!. Effect of delivery method on outcomes in the very low-birth weight breech infant: is the improved survival related to cesarean section or other perinatal care maneuvers? AM J OBSTET GYNECOL 1983;145:123-8.
Bound volumes available to subscribers Bound volumes of the AMERICAN JOURNAL OF OBSTETRICS AND GYNECOLOGY are available to subscribers (only) for the 1987 issues from the Publisher, at a cost of $51.00 ($74.00 international) for Vol. 156 (january-June) and Vol. 157 (july-December). Shipping charges are included. Each bound volume contains a subject and author index and all advertising is removed. Copies are shipped within 60 days after publication of the last issue in the volume. The binding is durable buckram with the JouRNAL name, volume number, and year stamped in gold on the spine. Payment must accompany all orders. Contact The C. V. Mosby Company, Circulation Department, 11830 Westline Industrial Drive, St. Louis, Missouri 63146, USA; phone (800) 325-4177, ext. 351. Subscriptions must be in force to qualify. Bound volumes are not available in place of a regular JOURNAL subscription.
Key words: Breech delivery, cesarean section
Cesarean delivery rates continue to increase in spite of National Institutes of Health consensus report recommendations to the contrary. The abdominal route of delivery is often chosen even when clear, convincing data fail to demonstrate any advantage over the vaginal route, with repeat cesarean sections representing the most significant example. Because breech delivery accounts for only 10% to 15% of all cesarean sections (3% of all deliveries) and because many authors advocate routine cesarean section for breech delivery, not much attention has been focused on this cesarean delivery indication. It is the purpose of this review to critically analyze the obstetric literature in order to answer the question of whether cesarean section for breech presentation results in better obstetric outcome when compared with vaginal delivery. An all-encompassing review of the breech literature is neither relevant to the above question nor within the scope of this communication. A more complete review of all breech data has recently been published.' Several key issues and their key references will, however, be discussed in more detail. Review of published data
Outcome comparisons of breech delivery and delivery in cephalic presentation, which may vary in magnitude, are nonetheless uniform in their results. For most of the important end points, infants born in breech presentation do worse than those in cephalic presentation. This comparison has been summarized by Seeds and Cefalo 2 (Table I). With this adverse outcome in mind, increasing use of cesarean section for breech delivery has occurred on the basis of the assumption that abdominal delivery would improve out-
From the Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, M aunt Sinai Hospital Medical Center and Rush Medical College. Supported by the Foundation of Reproductive Medicine, Chicago, IL 60610. Reprint requests: Stephen A. Myers, D. 0., Division of Maternal-Fetal Medicine, Mount Sinai Ho.1pital Medical Center, California Ave. at 15th St., Chicago, lL 60608.
6
Table I. Risks associated with breech · presentation Fetal risk
Approximate incidence
Prematurity Major anomalies Birth trauma Cord prolapse Intrapartum asphyxia Spinal cord injuries and deflexion Hyperextension of head Arrest of aftercoming head
16%-33% 6%-18% 13 times normal risk 5-20 times normal risk 3-8 times normal risk 21%
5% 8.8%
Modified from Seeds and Cefalo. 2
come. Major factors to be considered in analysis of this issue are: frank versus nonfrank breech presentation, the use of Piper's forceps, preterm breech delivery, and term breech delivery. Frank versus nonfrank breech
The observation has been made that nonfrank breech presentation is accompanied by increased perinatal mortality." This observation has been used tojustify the suggestion that patients with infants with nonfrank breech presentation not be allowed to labor. However, two important variables that affect outcome compound the analysis of nonfrank breech presentations-birth weight and cord prolapse. Goldenberg and Nelson 4 have demonstrated that the proportion of breech deliveries that are nonfrank increases as birth weight decreases. They reviewed the records of 141 patients with breech presentation who were delivered vaginally. Their findings reveal, in infants weighing <2000 gm, that 66% of all breech presentations are nonfrank, whereas only 33% are frank. Consequently, data comparing frank and nonfrank presentations alone may include differences in birth weight distribution that will also affect outcome and survival. A second factor may also compound outcome analysis comparing frank and nonfrank breech presentation. Nonfrank breech presentations are associated with significantly more instances of cord prolapse. 2
Breech delivery
Volume 156 Number I
7
Table II. The low birth weight breech Survival ratio of vaginal to cesarean deliveries Birth weight Years of study
Ratio of vaginal to cesarean deliveries
1970-1975
61/16
35/75
0
0
I 970-1975
47/18
0
0
0
1970-1977
II 9/32
35/75
0
0
Duenhoelter et al. 9 Mann and Gallant 15
I 972-1977
44/44 279/157
45/100 0
0 0
0 0
Effer et al. 16
1973-1980
67/95
0
0
0
Gimovsky et al. 6
1980
25/44
0/67
0
0
Main et al. 11
I 977-1981
123/93
42/71
0
0
Author
Woods'
Karp et al. 3 Bowes et al.
8
1000-1499,1500-1999,2000-2499 gm gm gm
Unless outcome analysis includes adjustments for these two potential biases, incorrect conclusions may follow. Two studies that do not have the above biases have failed to demonstrate any difference in outcome for frank and nonfrank breech delivery. Woods,' in a retrospective review of 73 breech deliveries, failed to show any difference in outcome of frank or nonfrank breech delivery. He also failed to show any benefit of cesarean section for either group. Similarly, Gimovsky et al., 6 in a prospective randomized study, failed to demonstrate a beneficial effect of cesarean section. In that study all infants with nonfrank breech presentation were randomized to either abdominal or vaginal delivery. The groups were comparable in birth weight and gestational age. No differences in the rate of mortality or trauma were demonstrated. In spite of these data, cesarean section continues to be recommended for nonfrank breech presentations. Piper's forceps
Milner7 has demonstrated that application of Piper's forceps to the aftercoming head will reduce neonatal mortality by one half in all birth weight groups. He observed a neonatal mortality of 162/1000 when Piper's forceps were not used, compared with 28/1000 when Piper's forceps were used. Moreover, this difference was still present when the data were analyzed by specific birth weight groups, for instance, for 1000 to 1499 gm birth weights, 22% mortality with forceps and 4 7% mortality without forceps. 7 Although these mortality figures are not directly comparable to more recent information, no published data refute Milner's conclu-
Comments
Head entrapment X 7 in vaginal group. Respiratory distress syndrome cause of mortality in >50% 17% prolapsed cord in nonfrank breech Includes 500-1500 gm birth weight since no difference with 500-999 gm documented 60% of deaths before 1974 No difference in 500-999 gm group. No difference in Apgar scores No difference in 500-999 gm group Similar for 500-999 gm group. Mortality only <1300 gm Includes 67 deliveries of 750999 gm
sion. Despite this observation, reports of vaginal breech delivery continue without either discussion of the use of Piper's forceps or tabulation of frequency of their usage. It can only be stressed that the use of Piper's forceps be more routinely applied and reported. Low birth weight breech
Perhaps the most controversial data regarding the effect of route of delivery on outcome are in the low birth weight breech group. Although fetopelvic disproportion does not occur, the possibility of head entrapment may be theoretically increased on the basis of the relatively larger head in a premature infant. Moreover, many authorities believe that premature infants are more susceptible to "trauma" during vaginal delivery. The eight most prominent studies covering this issue are summarized in Table II. Included in the table are the years in which the studies were performed, the total number of infants studied, and survivals in each of three birth weight groups. Inspection of these data reveals that no author was ever able to demonstrate a benefit of cesarean section in birth weights above 1500 gm, compatible with 30 to 31 weeks' gestational age, yet routine cesarean section generally is advocated for premature breech infants. Very low birth weight breech
Data for the very low birth weight breech infant deserve further scrutiny. Studies of Woods,' Bowes et al.,S and Duenhoelter et a!." share a common flaw. In the early 1970s, the viability of infants weighing < 1500 gm was clearly questioned. These three studies included
8
Myers and Gleicher
January 1987 Am J Obstet Gynecol
Table III. Mortality in very low birth weight breech deliveries (n = 37)
Table V. Recommendations for breech delivery Factors favoring vaginal delivery
Significance
500-999 gm 1000-1499 gm Mortality(%)
12 3 93
Sample <1000 gm (%)
80
9 13 33 41
p < 0.05 (authors' data) p < 0.05 (our calculation)
Modified from Gimovsky et al. 6
Table IV. Mortality in very low birth weight breech deliveries (n = 37) Vaginal
750-999 gm 1000-1249 gm 1250-1499 gm No. of deaths/ Total No. Sample < 1000 gm (%)
45/52 19/40 7/31 711123 (58%) 43
Cesarean section
9115 12/46 6/32 27/93 (29%) 16
Significance
NS NS NS p < 0.05 p < 0.05 (our calculation)
Modified from Main et a!. 11
patients who were delivered vaginally because they were thought in fact to carry previable infants. As an almost self-fulfilling prophecy, many of these infants subsequently died. Although cesarean section was occasionally carried out for maternal indications, it was usually only performed if the fetus was considered viable. Since the prognosis of viability was not prospectively controlled for in the management decisions of these three studies, the studies have to be considered of questionable validity and can be useful for comparative purposes only. Two of the later studies (Table II) warrant further discussion. Gimovsky and PauJI" reported a considerable benefit of cesarean sections in the very low birth weight group (Table III). However, 40% of deaths in their group delivered vaginally occurred in infants weighing <750 gm. Were these infants considered viable at Los Angeles County Hospital in 1980, or would they be considered as such even today? Moreover, the confounding effect of birth weight distribution differences between vaginal and abdominal groups was not considered. A significantly higher percentage of infants < 1000 gm occurred in the vaginal group compared with the abdominal group (80% vaginal versus 41% abdominal; p < 0.05, our calculation). Surely the effect of birth weight on survival cannot be ignored. An identical error was made by Main et a!." (see Table IV).
Birth weight <4200 gm Adequate pelvis Good progress of labor Absence of hyperextension of fetal head Factors favoring cesarean section
Birth weight >4200 gm Borderline pelvis Poor progress of labor (particularly descent) with adequate contractions Fetal distress Hyperextension of the fetal head
Although they correctly noted that there was no significant difference in survival in any of the three birth weight groups between 750 and 1500 gm, they chose to add the three weight groups together to come to the extraordinary conclusion that the vaginal delivery group did worse. In doing so, they failed to note that by lumping all three groups together, the vaginal group birth weights were skewed to those <1000 gm (43% under 1000 gm in the vaginal group versus 16% under 1000 gm in the cesarean group; p < 0.05, our calculation). Once again the confounding effect of birth weight on survival was interpreted as an effect of the route of delivery. The most definitive data published to date on route of delivery for very low birth weight infants were recently presented by Kitchen et a!. 12 from Melbourne. Their work included data on 326 infants born at 24 to 28 weeks' gestation between 1977 and 1982. Included in this group were 117 breech deliveries. The work of the Melbourne group stands out from all other published data for three major reasons. First, a prospective determination was made that all infants in the study were viable and consequently no infant's management was prejudiced by the expectation that the infant would die. Second, statistical analysis was performed with the use of a stepwise logistic regression analysis that took into account 14 different obstetric variables that could affect survival, including route of delivery. Last, and most important, half of the study infants were evaluated at 2 years of age with neurological and developmental assessments. We know of no other study of very low birth weight breech deliveries that includes these three crucial elements. The route of delivery was not prospectively randomized in the Melbourne study. It was assumed that vaginal delivery was safe and cesarean section was reserved for obstetric indications such as fetal distress and maternal disease. Only 16% of breech deliveries were by cesarean section. The authors found no difference between the two groups in either immediate or long-term outcome. Those advocating routine abdominal delivery for the very low birth weight
Breech delivery 9
Volume 156 Number 1
breech have no comparable data in support of their recommendation. Term breech
Regarding term breech deliveries the two most significant studies for current obstetric practice are by CoHea et a!. 13 and Green et a!. 14 CoHea et a!. 13 studied the outcomes of 208 patients with frank breech presentation at term in a prospective study with patients randomized to either vaginal or abdominal delivery. The conclusion of the authors was that vaginal delivery of the term frank breech was acceptable, provided patients fulfilled the minimum criteria of their study protocol. 13 There was no apparent advantage of cesarean section for the neonate. As expected, maternal morbidity was significantly greater in the abdominal delivery group. A more provocative observation was made by Green et al. 14 in Montreal. When they retrospectively observed the outcome of 600 term breech deliveries during the period 1963 through 1973, they noted that birth trauma and birth asphyxia occurred in 18% of the deliveries. The cesarean section rate for that group was 22%. They reasoned that this incidence of birth trauma and birth asphyxia, which they considered unnecessarily high, could be reduced by the more liberal use of abdominal delivery. By 1978, they had been successful in increasing their cesarean section rate to 94% of all breech deliveries. Subsequent review of their data for 1978 and 1979 (n = 175) again indicated an incidence of birth trauma and birth asphyxia of 18%. This experience clearly demonstrates that the increase in cesarean section rate did not affect breech outcome. The experience factor
It has been suggested that because today's obstetricians have inadequate experience with vaginal breech delivery, abdominal delivery represents a more prudent choice for "young practitioners." We reject this notion for several reasons. First, ignorance about the technique of breech delivery can result in trauma in both vaginal and abdominal delivery. A fetus will thus not benefit from abdominal delivery if the delivery technique used is inappropriate. It is the profession's responsibility to provide training in breech delivery technique during the residency period. During this time a house officer has the opportunity to accumulate a concentrated, supervised experience, unmatched by any subsequent period of his or her professional life. The education of young physicians has to be the responsibility of senior obstetricians who have accumulated sufficient clinical experience in breech delivery to serve in a consulting capacity. Within such an educational framework, one could in fact foresee that these senior consultants will be available during
vaginal breech deliveries at their institutions. Patients could thus be assured that breech deliveries are performed by the most experienced obstetrician in the safest way for mother and infant. After all, inexperience should never be the reason for a surgical solution. Experience is usually available. Cost consideration
Cesarean section, compared with vaginal delivery, costs an additional $2700 per patient in hospital cost alone. Among 3.5 million deliveries per year in the United States, approximately 122,500 are in breech presentation. Currently, national cesarean section figures suggest that approximately 70% to 80% of all breech deliveries are performed by cesarean section. If the above-mentioned data from the Melbourne 14 and Montreal' 6 groups are representative and a 20% cesarean section rate can safely be applied, 50% to 60% of breech deliveries (60,000 to 70,000 deliveries per year) are at present subjected to unnecessary cesarean sections. The annual national hospital cost for unnecessary cesarean sections for breech presentation thus approaches $200,000,000 per annum. These cost calculations do not include added costs for physician services, etc. Improved neonatal outcome could justify such cost. As should be evident, from the above-presented data, however, no such benefit exists. Recommendation
On the basis of the review of obstetric literature, we suggest that previously held risk factors for vaginal delivery, such as nonfrank breech presentation, parity, and low or very low birth weight, are not associated with increased risk for birth trauma or birth asphyxia when vaginal delivery is compared with cesarean section. Patients presenting in labor with breech presentation must have the following: (1) ultrasound examination to exclude obvious anomalies, check placental localization, corroborate clinical estimate of fetal weight, and evaluate the angle between the cervical and thoracic spine; (2) clinical or x-ray pelvimetry if estimated fetal weight is >3500 gm or to corroborate hyperextension of the fetal head if ultrasound is unavailable or inadequate; (3) continuous electronic fetal monitoring; (4) adequate documentation of normal progress of labor. Should risk factors known to be associated with adverse outcome develop, cesarean delivery is to be used (see Table V). On the basis of the Montreal and Melbourne experience, 14 ' 16 the need for abdominal delivery should, however, not exceed 20% to 25% of all breech deliveries. Effective cesarean section monitoring programs for breech presentations therefore need to be developed. Such programs could include mandatory chart review and could be designed to tabulate which risk factors for vaginal breech delivery
10 Myers and Gleicher
have been documented on the chart. However, peer review can only be effective if a consensus develops in the professional's above-outlined guidelines. Most important, such an approach could be taken with confidence that no adverse effects on either mother or newborn infant would occur. REFERENCES I. Confino E, Gleicher N, Elrad H, Ismajovich B, David M. The breech dilemma. A review. Obstet Gynecol Surv 1985;40:330-6. 2. Seeds S, Cefalo R. Breech delivery. Clin Obstet Gynecol 1985;25: 145-56. 3. Karp LE, Doney JR, McCarthy T, Meis PJ, Hall M. The premature breech: trial of labor or cesarean section? Obstet Gynecol 1979;53:88-92. 4. Goldenberg RL, Nelson KG. The premature breech. AM j 0BSTET GYNECOL 1977;127:240-4. 5. Woods JR. Effect of low birth weight breech delivery on neonatal mortality. Obstet Gynecol 1979;53:735-40. 6. Gimovsky ML, Wallace RL, Shifrin BS, et a!. Randomized management of the nonfrank breech presentation at term: a preliminary report. AM j 0BSTET GYNECOL 1983; 146:34-40. 7. Milner RDG. Neonatal mortality of breech deliveries with and without forceps to the aftercoming head. Br J Obstet Gynaecol 1975;82:783-5. 8. Bowes WA Jr, Taylor ES, O'Brien M, Bowes C. Breech
January 1987 Am J Obstet Gynecol
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delivery: evaluation of the method of delivery on perinatal results and maternal morbidity. AM J OBSTET GYNECOL 1979; 135:965-70. Duenhoelter JH, Wells E, Reisch JS, et a!. A paired controlled study of vaginal and abdominal delivery of the low birth weight breech fetus. Obstet Gynecol 1979;54: 310-3. Gimovsky ML, Paul RH. Singleton breech presentation in labor: experience in 1980. AM j 0BSTET GYNECOL 1982; 143:733-9. Main DM, Main EK, Maurer MM. Cesarean section versus vaginal delivery for the breech fetus weighing less than 1500 grams. AMj 0BSTET GYNECOL 1983;146:580-4. Kitchen W, Ford GW, Doyle LW, eta!. Cesarean section or vaginal delivery at 24 to 28 weeks' gestation: comparison of survival and neonatal and two-year morbidity. Obstet Gynecoll985;66:149-57. ColleaJV, Chein C, Quilligan EJ. The randomized management of term frank breech presentation. A study of 208 cases. AMj 0BSTET GYNECOL 1980;137:235-42. Green JE, McLean F, Paul Smith L, eta!. Has an increased cesarean section rate for term breech deliveries reduced the incidence of birth asphyxia, trauma, and death? AM j 0BSTET GYNECOL 1982; 142:643-8. Mann L, GallantJM. Modern management of the breech delivery. AM j 0BSTET GYNECOL 1979;134:611-4. Effer B, Saigal S, Rand C, eta!. Effect of delivery method on outcomes in the very low-birth weight breech infant: is the improved survival related to cesarean section or other perinatal care maneuvers? AM J OBSTET GYNECOL 1983;145:123-8.
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