Planned cesarean delivery in breech presentation at term is associated with a reduction in infant mortality and morbidity. 1,2 However, the rates of perinatal mortality and long-term complications for the infant are low, 1,3 and the benefit for the fetus should be balanced by the risk of maternal complications associated with elective cesarean delivery. Also, women and obstetricians choose an intended and not actual mode of delivery. That is important, as nearly one third of planned vaginal deliveries result in an emergency cesarean delivery, and some women who intend to have an elective cesarean delivery have vaginal or emergency cesarean deliveries before the scheduled operation. 1,4 Furthermore, there is evidence that maternal complications are more common with emergency than with elective cesarean deliveries. 5
Previous studies on maternal morbidity and mortality after cesarean delivery are inconclusive or hampered by the fact that the women having cesarean delivery have conditions, pregnancy complications, and/or delivery complications that are themselves associated with increased maternal morbidity/mortality. Also, most studies combine elective and emergency cesarean delivery, which have different complication rates. Thus, it has not been possible to conclude whether the cesarean delivery as such or the intended mode of delivery was associated with increased risk.
The objective of the present study was to examine the implications of mode of delivery in breech presentation at term, in terms of maternal mortality, puerperal morbidity, subsequent hospitalizations, or surgery for gynecologic problems, including urinary and anal incontinence, fecundity, fetal outcome, and obstetric complications in subsequent pregnancies.
MATERIALS AND METHODS
In Denmark, the Medical Birth Register contains information on all births until 1995, based on notifications completed by midwives.
Information on all hospitalizations in Denmark is electronically stored in the National Patient Register with codes for operations, interventions, and diagnoses at discharge. Diagnoses are coded according to the World Health Organization's International Classification of Diseases (8th revision applied 1982–1993 and 10th revision applied 1994–2000). Operations and interventions are coded by Classification of Surgical Procedures and Treatments (version 3, 1982–1995), and the Nordic Classification of Surgical Procedures (version 1, 1996–2000).
The Register of Death Causes contains dates and causes of deaths, based on diagnoses on the death certificate.
A cohort of all primiparas who delivered a singleton infant in breech presentation at term in Denmark during 1982–1995 was identified in the Medical Birth Register, and information on mode of delivery (elective cesarean, vaginal, emergency cesarean) and other relevant obstetric variables (birth weight, intrapartum or early neonatal death, “smoker at first consultation” (midwife), gestational age, Apgar score, episiotomy, forceps delivery) were retrieved from the register.
The cohort was described by information from the Register of Death Causes on date and cause of death through 1998.
Specific diagnoses from actual delivery (rupture of anal sphincter, bladder lesion, diabetes in pregnancy, hypertensive disorder), all complications until 6 weeks postpartum (pelvic infection, puerperal fever, operation for wound infection, hysterectomy), and subsequent and future diagnoses and operations from hospitalizations until year 2001 for gynecologic and obstetric conditions and complications (vesicovaginal fistula, vaginal descensus, uterine rupture, urinary or anal incontinence) were retrieved from the National Patient Register.
Also, the cohort was merged with the Birth Register to obtain information on later pregnancies, including perinatal death, time of death in relation to birth, Apgar score, elective cesarean delivery, emergency cesarean delivery, intervention during labor, placental complications, gestational age, birth weight, and presentation at birth.
Data were received in anonymous, case-based form from the National Board of Health and analyzed by the SPSS 11.0 for Windows statistical program (SPSS, Inc., Chicago, IL). The differences between the groups were examined by t test, χ2, and Fisher exact test.
During the study period, a total of 732,559 infants were born. A cohort of 15,441 (2.1%) primiparas with a singleton infant in breech presentation at term was identified and classified by the actual mode of delivery. A total of 7503 (48.6%) women were delivered by elective cesarean (cesarean delivery before labor), 2363 (15.3%) vaginally, and 5575 (36.1%) by emergency cesarean delivery (cesarean delivery after onset of labor) (Table 1). Mode of delivery did not change during the study period (Figure 1).
Epidemiologic and obstetric characteristics of the cohort according to mode of delivery are described in Table 1. The rates of intrapartum or early neonatal death and low 5-minute Apgar score were lower in infants delivered by elective cesarean, compared with infants delivered vaginally or by emergency cesarean. In women with elective cesarean delivery, more women were less than 20 years or 35 or more years old at delivery. Women with elective cesarean delivery more often had hypertensive disorders or diabetes in pregnancy, compared with women who delivered vaginally. In women who delivered vaginally, 5.1% were delivered by forceps, and 47.6% had episiotomy.
From 1982 to 1998, a total of 83 women (0.5%) from the cohort died. Three women, all with emergency cesarean at first delivery, died in relation to pregnancy and childbirth. Two primiparous women died 40 and 55 days after emergency cesarean delivery. Both had a diagnosis of hypertensive disorder of pregnancy and puerperium. One woman died from a pulmonary embolism 39 days after her second delivery. Her first delivery was by emergency cesarean, but the second was an uncomplicated vaginal delivery.
The rate of deaths in the cohort was higher subsequent to a first emergency cesarean delivery than a first vaginal delivery. When comparing the group of women with vaginal delivery or emergency cesarean delivery with women with elective cesarean delivery, there was no difference.
The majority of the 83 deaths were related to cancer (45.8%). Medical disease (including acquired immunodeficiency syndrome, cerebral hemorrhage and infarction, pulmonary embolism not related to pregnancy, infections, and heart diseases) was the cause of death in 15.7% of the cases. Suicide and death related to the abuse of alcohol or narcotics were responsible for 12.0% and 7.2% of the deaths, respectively, and 7.2% died as a result of an accident (Table 2).
Elective cesarean delivery was associated with lower risk of puerperal fever and pelvic infection (relative risk [RR] 0.81; 95% confidence interval [CI] 0.70, 0.92), hemorrhage and anemia (RR 0.91; 95% CI 0.84, 0.97), and operation for wound infection (RR 0.69; 95% CI 0.57, 0.83) compared with emergency cesarean delivery, but with a higher risk of puerperal fever and pelvic infection (RR 1.20; 95% CI 1.11, 1.25) compared with vaginal delivery. The frequency of bladder injuries sutured during elective and emergency cesarean deliveries were 0.1% and 0.2%, respectively (Table 3).
There were 13 cases of thromboembolism in women with cesarean delivery (0.1%) and none in those delivered vaginally (not significant). The rate of thromboembolism was not correlated with type of cesarean delivery (Table 3). No women underwent hysterectomy in the puerperium.
Among the vaginal deliveries, 1.7% of the women had a rupture of the anal sphincter.
Hospitalization with vaginal descensus or urine incontinence was not significantly related to mode of delivery and was reported in 13 (0.6%) women who delivered vaginally, 42 (0.6%) delivered by elective cesarean, and 80 (0.5%) delivered by emergency cesarean in the follow-up period (5–18 years after the first delivery). The mean age at first delivery in women with urinary incontinence or vaginal descensus did not differ between the three groups. There were no cases hospitalized with a diagnosis of fistula or anal incontinence.
The number of admissions to hospital with a diagnosis of infertility was 79 (1.1%) after elective cesarean delivery, 23 (1.0%) after vaginal delivery, and 61 (1.1%) after emergency cesarean delivery. Ectopic pregnancies were recorded in 184 (2.5%) women with elective cesarean delivery, 66 (2.8%) with vaginal delivery, and 144 (2.6%) with emergency cesarean delivery. Hospitalization with miscarriage was recorded in 508 (6.8%) women with elective cesarean delivery, 167 (7.1%) with vaginal delivery, and 409 (7.3%) with emergency cesarean delivery.
A significantly lower proportion of women delivered by elective cesarean (55%) had a subsequent child, compared with 61% of those delivered vaginally (RR 0.94; 95% CI 0.92, 0.96) and with 59% of those delivered by emergency cesarean (RR 0.91; 95% CI 0.88, 0.95). Adjusting for age and medical condition at first delivery (ie, including only women younger than 30 without diabetes, hypertensive disorders, or perinatal death during the first pregnancy), the rates of women with a second child were 61% in the group with a first elective cesarean delivery, 64% in the group with a first vaginal delivery, and 64% in those with a first emergency cesarean delivery (Table 4).
Women delivered by elective cesarean in their first pregnancy more often had repeated breech presentation in their second pregnancy (16%) than those with a first vaginal delivery (12%) (RR 1.05; 95% CI 1.02, 1.09). Women with elective cesarean delivery in their first pregnancy were also more often delivered by elective cesarean in their second pregnancy (16%), compared with those with a first vaginal delivery (5%) (RR 1.25; 95% CI 1.21, 1.29) (Table 5).
Mode of delivery in first pregnancy did not influence the perinatal outcome of the second or third pregnancy in terms of Apgar score and perinatal death.
The incidences of placental abruption and placenta previa in the second or third pregnancy of women with an elective cesarean delivery in first pregnancy did not differ significantly from those delivered vaginally.
Uterine rupture in second or third pregnancy occurred in five women (0.1%) with a first elective cesarean delivery, in two (0.05%) with a first emergency cesarean delivery, and in none of those delivered vaginally. This difference is not statistically significant (Table 6).
We studied pregnant women with breech presentation at term. The main reason for choosing a cesarean mode of delivery in these women is the increased risk for the infant or a maternal desire for planned operative delivery. Otherwise, they do not differ significantly from the background population regarding maternal risk at delivery. Thus, the outcomes of the present study are also relevant for pregnant women considering elective cesarean delivery without other obstetric indications.
Previous studies on maternal risk include a randomized, controlled trial and a meta-analysis of controlled studies. In the randomized, controlled trial of 2083 term breech pregnancies, intended cesarean delivery was not associated with a higher risk of maternal mortality or morbidity in the first 3 months postpartum. 1,6 However, the size of the study was inadequate to detect significant differences in rare but serious complications. Moreover, because of the prospective design of the study, it will take many years before results on long-term morbidity and complications in future pregnancies are available.
A meta-analysis of studies published between 1966 and 1992 of planned cesarean delivery compared with planned vaginal delivery for breech presentation at term showed that planned vaginal delivery was associated with a lower short-term maternal morbidity and mortality (odds ratio 0.61; 95% CI 0.47, 0.80) than planned cesarean delivery. 7
In the present study, the rate of direct obstetric deaths in relation to a first delivery of breech was 130 per million (2 per 15,441), and the two deaths occurred in women delivered by emergency cesarean (359 per million). According to confidential inquiries into maternal deaths in the United Kingdom from 1994 to 1996 (2,197,567 deliveries), the rates of death per million were 20.6 after vaginal delivery, 58.5 after elective cesarean delivery, and 182.0 after emergency cesarean delivery (Hall M, Bewley S. Maternal mortality and mode of delivery [letter]. Lancet 1999;354:776). 8
The incidence of hemorrhage and anemia after elective cesarean delivery (5.7%) did not differ from that after vaginal delivery and was lower than after emergency cesarean delivery (7.0%). This is in accordance with a study from the Netherlands, in which a blood loss of more than 1000 mL occurred in 4.7% of elective cesarean deliveries. 5 Also, surgical interventions for wound infection and pelvic infection or puerperal fever was more frequent in women delivered by emergency cesarean. However, recommendations on routine use of prophylactic antibiotics introduced in recent years might have reduced the current rates of infections.
Thromboembolism is the major cause (36%) of maternal death in the United Kingdom. 8 Even when thromboembolism is not fatal, it is a serious complication often associated with postthrombotic sequelae and a need for prolonged medical treatment. In the present study, there were no cases of thromboembolism in the group delivered vaginally, and the rates were 0.1% in both cesarean delivery groups.
Anal sphincter rupture at vaginal delivery is associated with a subsequent risk of anal incontinence. 9 The fear of anal sphincter rupture is one of the main reasons for elective cesarean delivery on maternal request. The rate of sphincter rupture in the present study was 1.7%, which suggests a risk of subsequent flatus incontinence of 0.7% to 0.9% subsequent to a vaginal delivery.
Surgical trauma to the bladder is usually repaired during the cesarean delivery. Subsequently, the woman carries a urine catheter for about 1 week, usually without other complications or sequelae. 10 In the present material it was less frequent during elective (0.1%) than during emergency cesarean delivery (0.2%).
In follow-up studies, vaginal delivery has been found to increase the risk of urinary incontinence 3–6 times. 11,12 In this study, the total incidences of diagnosis of or operation for vaginal descensus or incontinence were approximately 0.5%, regardless of mode of delivery. The low rate and the lack of difference by mode of delivery may reflect the short follow-up period of less than 18 years and the fact that only serious complications leading to hospitalization are included.
Ectopic pregnancy and miscarriage subsequent to the first delivery were not correlated with mode of delivery. In a Finnish register–based study, primiparas with cesarean delivery had a significantly increased risk of subsequent miscarriage (RR 1.22). 13
Recurrence of breech presentation in second pregnancy was high (15%). This is consistent with data reported from the Medical Birth Registry of Norway. 14 Interestingly, breech presentation was more often repeated in women who had elective cesarean delivery in their first pregnancy than in those delivered vaginally. A tentative explanation for this association may be that in cases in which the presentation is caused by maternal factors, such as uterus malformation or pelvis abnormalities, women are more often offered repeated elective cesarean delivery. However, the influence of fetal causes, such as recurrent growth restriction, cannot be excluded. Even with a 15% risk of breech at term in the second pregnancy, the rate of vaginal delivery after cesarean delivery in the first pregnancy was as high as 72%.
The relationship between cesarean delivery and placenta previa (RR 3.78–5.34) has been documented in previous studies, with a rate of 0.27% in pregnancies after a first cesarean delivery. 13 The rate was nonsignificantly lower in our study and did not differ by mode of delivery, possibly because of size of the population.
The rates of placental abruption after cesarean delivery were similar in our study (0.3%) and in the population of Finland (0.4%). In the Finnish study 13 there was a significant increase of placental abruption after cesarean delivery.
Uterine rupture occurred in 1 per 1000 women with elective cesarean delivery. Previous studies have reported a rate of uterine rupture during intended vaginal delivery after cesarean delivery of 0.8% 15 and up to 2.5% after induction of labor with prostaglandin. 16 One explanation of the lower rate of uterine rupture in our study could be that the risk of uterine rupture in vaginal birth after cesarean delivery might be lower in women delivered by cesarean indicated by breech than in women with cesarean delivery indicated by fetal–pelvic disproportion.
The 20–50% lower risk of preterm or low birth weight infants in pregnancies subsequent to elective cesarean delivery might be due to selection bias, because elective cesarean delivery of term breech is preferred when birth weight is high, which implies a low risk of preterm or low birth weight infants in subsequent pregnancies.
In conclusion, elective cesarean delivery for breech at term implies a low risk of severe medical complications for the mother. It seems that a recommendation of elective cesarean delivery is associated with a similar or even lower risk of maternal complications than a recommendation of vaginal delivery, which includes a risk of emergency cesarean delivery.
In a clinical context, the results of the present study support a recommendation of elective cesarean delivery for breech at term to women who consider medical consequences more important than the rewarding experience of a natural birth.