Conservative management in breech deliveries leads to similar results compared with cephalic deliveries

Objective.?To compare the difference in neonatal mortality and morbidity between breech and cephalic presentations at term.

Methods.?This was a retrospective matched cohort study in two centers between July 1998 and April 2000, including all breech deliveries between 37⁺⁰ and 41⁺⁶ weeks, except cases with multiple gestations and antepartum intrauterine deaths. All breech presentations were matched with two cephalic presentations. Onset of labor and route of delivery were recorded, and neonatal data were categorized into variables belonging to serious morbidity or moderate morbidity.

Results.?One thousand one hundred and nineteen deliveries were included. Three hundred and seventy-three babies were in breech position and 746 in cephalic position. The gestational age and birth weight of the babies in the breech group were lower than in the cephalic group (p < 0.001). Congenital abnormalities occurred more often in the breech group (p < 0.005). An elective cesarean section was performed in 23.3% of breech presentations versus 3.5% of cephalic presentations (p < 0.001). Emergency cesarean sections were done in 29.2% of breech presentations versus 8.8% of cephalic presentations (p < 0.001). Children born in breech presentation had lower Apgar scores after 1 minute (p < 0.0001), but 5-minute Apgar scores were the same in both groups (p = 0.22). Children born in breech presentation received significantly more resuscitation than children born in cephalic presentation (p < 0.001). In both groups no perinatal mortality occurred. No differences were observed in percentages of children with serious or moderate neonatal morbidity between the breech and cephalic lies.

Conclusions.?Although the numbers are small, this study shows that the conservative (vaginal) approach in selected fetuses in breech position can be safely pursued with neonatal results similar to fetuses in cephalic presentation.     

The mode of delivery and neonatal outcome in breech presentations less than 32 weeks' of gestation

This study was undertaken to determine the effect of the delivery method on neonatal outcome in fetal breech presentation, and the following results were obtained. The rate of cesarean section for breech presentations was 70.7% (104/147). 1) There were 18 neonatal deaths (41.9%) in 43 vaginal breech deliveries compared to 8 (7.7%) in 104 cesarean breech deliveries. Neonatal deaths were significantly higher in vaginal breech deliveries than cesarean breech deliveries (p less than 0.001). 2) In breech presentations, intracranial hemorrhages were more common among vaginally born infants (44.2% vs. 25.0%; p less than 0.02), but the incidence of idiopathic respiratory distress syndrome (39.5% vs. 28.8%) did not differ significantly between vaginal and cesarean infants. 3) In singletons delivered vaginally, fetal distress was more common among breech presentations than vertex presentations (83.3% vs. 46.3%; p less than 0.02). 4) In vaginally delivered breech singletons, there was no neonatal death among infants with more than 4 one minute Apgar scores, and there was no significant difference between neonatal death and the no neonatal death groups with regard to gestational weeks and birth weight.     

Good perinatal outcome in selective vaginal breech delivery at term

BACKGROUND AND AIM: To compare perinatal outcome in groups of planned vaginal breech delivery, elective cesarean section with the fetus in breech presentation, and planned vaginal delivery with the fetus in cephalic presentation in a university hospital with a tradition of managing breech deliveries by the vaginal route. METHODS: A cohort study from a 7-year period 1995-2002, including 590 planned vaginal deliveries with a term (> 37 weeks) singleton fetus in breech presentation, 396 elective cesarean sections with a term singleton fetus in breech presentation, and 590 control women intending vaginal delivery with a singleton term fetus in cephalic presentation. RESULTS: The Apgar scores were lower in the group of planned vaginal breech delivery, but in other outcome measures there were no significant intergroup differences. The overall neonatal morbidity was small (1.2% vs. 0.5% vs. 0.3% in the respective study groups) if compared to a recently published randomized multicenter study. CONCLUSIONS: Selective vaginal breech deliveries may be safely undertaken in units having a tradition of vaginal breech deliveries.     

Mode of delivery and outcome of 699 term singleton breech deliveries at a single center

OBJECTIVE: Elective cesarean delivery has been postulated to improve the outcome of term fetuses in breech presentation. We retrospectively compared the short- and long-term outcomes of term infants who were delivered from a breech presentation at a single center. STUDY DESIGN: We reviewed 699 consecutive term breech presentations according to the intended mode of delivery at a single center between January 1993 and December 1999. The short-term outcome measures were perinatal death, neonatal death, or serious neonatal morbidity; the long-term outcome measures were developmental delay and spasticity. RESULTS: The rate of serious perinatal morbidity in the trial-of-labor and cesarean delivery groups was 2.3% and 0.5%, respectively (P =.12). There was no perinatal or neonatal death in either group. With a median follow-up period of 57 months (range, 13-100 months), the rate of developmental delay was 1.9% and 0.5%, respectively (P =.29). Spasticity was not noted in any of the children. CONCLUSION: Our data suggest that planned vaginal delivery remains an option for selected term breech presentations.     

Cesarean vs. vaginal birth for term breech presentation in 2 different study periods.

OBJECTIVE: To compare outcomes for fetuses at term in breech presentation during 2 periods when different delivery policies were in effect. METHODS: Outcomes of the 392 planned vaginal deliveries and 1160 elective cesarean sections (CSs) performed from January 1, 1988, through December 31, 2000, were compared with those of the 24 emergency vaginal deliveries, the 403 planned CSs, and 75 emergency CSs performed from January 1, 2001 through December 31, 2004 at Alexandra Hospital, Athens, Greece. RESULTS: A significant difference was found in rates of low 5-minute Apgar score, birth trauma, serious neonatal morbidity, and admission to the neonatal intensive care unit (0% vs. 1.02% [P=0.004], 1.02% vs. 0% [P=0.004], 3.06% vs. 0.43% [P<0.001], and 2.8% vs. 0.43% [P<0.001], respectively) between neonates born by planned vaginal delivery and those born by elective CS during the first period. Only a reduction in rates of admission to the neonatal intermediate care unit was found between the first and second periods. CONCLUSIONS: Planned CS was found to be safer than planned vaginal delivery for fetuses at term in breech presentation. However, the study did not demonstrate that the change in policy improved neonatal outcome.     

Outcomes of a Breech Birth Program in Canada,Quality Assurance Project

ObjectiveTo report antenatal, intrapartum, and postnatal factors associated with breech birth from our Breech Program at South Health Campus, Calgary.MethodsWe reviewed all maternal and neonatal patient records where breech birth was documented from 2013 to 2018. Neonatal blood gas values, Apgar scores, birth weight, admissions to NICU, antenatal ultrasound reports, inpatient electronic medical records, and operative and delivery reports, were reviewed. Any indices known as indications, contraindications, or outcomes associated with breech birth were recorded and summarized.ResultsAmong the 499 breech births that occurred over the study period, there were109 attempted external cephalic versions, 411 planned and 39 unplanned cesarean deliveries, and 49 vaginal deliveries. Unplanned cesarean delivery was performed for newly diagnosed breech presentation in labour (14), footling presentation in labour (9), abnormal fetal heart rate (4), labour dystocia (8), ultrasound findings of low fluid (2) or unfavourable fetal position (1), and worsening maternal hypertension (1).ConclusionDespite the absence of reported contraindications in the majority of patients and the presence of a program that supported vaginal breech delivery, cesarean delivery was more common. Mothers who chose to labour were highly successful in achieving vaginal birth with excellent maternal and neonatal outcomes.     

A comparison of the neonatal morbidity of second twins to that of a low-risk population

OBJECTIVE: To assess the neonatal morbidity of second twins. STUDY DESIGN: Cohort study in a department of perinatalogy. The neonatal morbidity of second twins was compared to that of a low-risk population: singletons in the cephalic presentation delivered vaginally. RESULTS: Five hundred fifty-nine second twins and 18,061 vaginally delivered singletons in the cephalic presentation were studied. Of 452 (81%) second twins delivered vaginally, 310 (69%) were extracted using obstetrical maneuvers: internal version and breech extraction, breech extraction alone, or assisted breech delivery if the breech was already engaged. Before 33 weeks of gestation, there was no significant difference between the neonatal morbidity of the vaginally delivered second twins and the vaginally delivered singletons in the cephalic presentation. After 33 weeks of gestation, only the 1-min Apgar score <7 and the rate of intubation at birth were significantly higher in the second twins. Whatever the gestational age, there was no significant difference between the neonatal morbidity of the vaginally delivered second twins and that of the second twins born by cesarean section before labor. At comparable gestational ages, there was no significant difference between the death rate of the vaginally delivered second twins and that in the reference population. CONCLUSION: The neonatal morbidity of second twins was comparable to that of a low-risk population. Immediate management of the vaginally delivered second twins was, however, more intensive than that of vaginally delivered singletons in the cephalic presentation. It, therefore, requires appropriate equipment in a suitable obstetric-pediatric setting.     

Breech presentation: evolution of management

From the historical perspective, vaginal delivery of the persistent breech presentation had been the tradition since the 1st century A.D. The external cephalic version was perfected and popularized in the mid-16th century. A variety of instruments and maneuvers had been used in the 19th century, with successful application of forceps to the after-coming head, and in 1924, Edmund Piper developed forceps for application only to the after-coming head. Vaginal delivery of breech cases had been performed primarily for the safety of the mother. As blood banking, antibiotics and safe anesthesia became available and legal and the ethical and social milieu was changing, cesarean breech deliveries were performed more liberally to reduce the increased perinatal morbidity and mortality of infants born of vaginal breech deliveries. Liberalization of cesarean delivery resulted in increased maternal mortality, and increased maternal morbidity created potential hazards in subsequent pregnancies. Renewed interest in revival of the practice of external cephalic version created successful reduction in term breech presentation. Several retrospective, prospective and randomized studies of vaginal deliveries of some types of breech cases were conducted under strict, selective protocols, with results of outcome comparable to those of cesarean sections. The International Term Breech Collaborative Group, after study of a large number of frank and complete breech cases, concluded that planned cesarean delivery is a "substantially better method of delivery for the fetus" and that a policy of planned vaginal birth for term, singleton, breech fetuses should no longer be encouraged.     

Comparison of vaginal and cesarean section delivery for fetuses in breech presentation

OBJECTIVES: Our purpose was to evaluate the perinatal mortality and morbidity of deliveries with fetuses presenting by the breech comparing outcomes of two groups according to mode of delivery: vaginal and cesarean section. RESULTS: Of 756 fetuses studied, 271 were delivered vaginally and 485 by cesarean section. In infants weighing > or = 1500 grams, "further corrected" mortality and morbidity rates were low and similar for both delivery routes: one neonatal death (NNM) in each. Among very low birth weight (VLBW) infants (< 1500 grams) the "further corrected" mortality rate was higher in the vaginal group: 57.4%, and 18.0% in abdominal deliveries (odds ratio [OR] = 6.1, 95% CI: 3.1 to 12.1). Likewise, rate of depression at five minutes were higher in the vaginal group (p < 0.001). However, the average fetal weight among the vaginal deliveries VLBW (787 grams) was 250 grams less than in the cesarean section group (1040 grams). After adjustment for fetal weight, gestational age, and other prognostic variables the odds ratio for neonatal death was no longer statistically significant (adjusted OR = 2.1, 95% CI: 0.9 to 5.2, p = 0.105). Comparison of planned vaginal delivery with elective cesarean section yielded smaller differences (adjusted OR for neonatal death = 1.3, 95% CI: 0.6 to 2.9, p = 0.525). CONCLUSION: The poor perinatal outcomes of breech delivered infants are due primarily to VLBW, congenital malformations, and premature labor. Although abdominal delivery had a lower NNM rate than vaginal delivery, the difference was not significant after adjustment for confounding factors. The results confirm the findings of a previously analyzed similar series delivered at our institution between 1980 and 1987. They suggest that, with appropriate technique, abdominal delivery is not mandatory in breech presentation.     

Vaginal breech delivery at term and neonatal morbidity and mortality – a population-based cohort study in Sweden

Introduction: The routine to deliver almost all term breech cases by elective cesarean section (CS) has continued to be debated due to the risk of maternal and neonatal complications. The aims of the study were (1) to investigate if mode of delivery impacts on the risk of morbidity and mortality among term infants in breech presentation and (2) to compare the rates of severe neonatal complications and mortality in relation to presentation and mode of delivery.

Methods: This population-based cohort study used data from the Swedish Medical Birth Register. All women (and their newborn infants) with singleton pregnancies who gave birth at term to an infant in breech (n?=?27,357) or cephalic presentation (n?=?837,494) between 2001 and 2012 were included. Births with vacuum extraction and induced labors were excluded, as well as antepartum stillbirths, births with infants diagnosed with congenital malformations and multiple births.

Results: On one hand, the rates of neonatal complications and mortality were higher among infants born in vaginal breech compared to the vaginal cephalic group. On the other hand, after CS, the rates of all neonatal complications under study and neonatal mortality were lower among infants in breech presentation than in those in cephalic presentation. After adjustment for confounders, infants delivered in vaginal breech had 23.8 times higher odds AOR (ratio) for brachial plexus injury, 13.3 times higher odds ratio for Apgar score <7 at 5?min, 6.7 times higher odds of intracranial hemorrhage (ICH), or convulsions and 7.6 higher odds ratio for perinatal mortality than those delivered by elective CS.

Conclusions: Despite a probable selection of women who before-hand were considered at low risk and, therefore, could be recommended vaginal breech delivery, infants delivered in vaginal breech faced substantially increased risks of severe neonatal complications compared with infants in breech presentations delivered by elective CS.

• Key message

• Vaginal breech delivery is associated with increased risk for severe neonatal complications.

     

Evaluation of a feto-pelvic scoring system in the management of breech presentations

A feto-pelvic scoring system comprising maternal pelvimetric data, estimated fetal weight, type of breech presentation and previous obstetric history was used in selecting patients for cesarean section of vaginal delivery. A maximum score of 20 points was possible. Twelve points or less indicated cesarean section. During 1973-1975 224 singleton breech deliveries were evaluated. In 29.5% cesarean section was performed and in 83% of these it could be planned in advance. In 70.5% of cases, patients were allowed to deliver vaginally under continuous electronic monitoring of the fetal heart rate. There was one intrapartum death and only one early neonatal death of a small premature child. In two cases intrauterine death had occurred already in the antepartum period. The uncorrected perinatal mortality was 17.9 per 1000 but not significantly different from the uncorrected perinatal mortality of 8.0 per 1000 for all patients delivered at the Danderyd's Hospital during the period 1972-1975 (12832 births). The corrected mortality resulting from breech presentation was 8.9 per 1000. The infants exhibited similar and excellent 5 min Apgar scores whether delivered vaginally or by cesarean section or matched with a randomized control series of 1000 cephalic presentations.     

Six hundred and ten breech versus 12,405 cephalic deliveries at term: is there any difference in the neonatal outcome?

OBJECTIVES: To compare neonatal morbidity of breech and cephalic deliveries at term. STUDY DESIGN: Cohort study of 610 consecutive singleton breech presentations and 12,405 consecutive singleton cephalic presentations in term between 1992-1998. Five hundred and fourteen breech and 11,989 cephalic presentations were candidates for vaginal delivery, of which 407 (79%) breeches and 11,265 (94%) cephalic delivered vaginally. RESULTS: Neonatal intensive care admissions were significantly greater for breech than cephalic vaginal deliveries (2.7% versus 0.25%, P = 0.000), but newborn intensive care admission and mortality were equally distributed between the two groups. CONCLUSIONS: A low caesarean rate is possible (21% beech and 6% cephalic). Neonatal morbidity was equal in the two populations. Admission to neonatal intensive care was significantly more frequent for caesarean section than for vaginal delivery in the cephalic group and equal in the breech group. This study justifies our obstetrical policy and the realisation of a trial in several centres similar in terms of perinatal management.     

Randomized management of the second nonvertex twin: vaginal delivery or cesarean section

Sixty twin deliveries after the thirty-fifth gestational week with vertex-breech and vertex-transverse presentations were managed according to a randomization protocol. Thirty-three parturient women (21 vertex-breech and 12 vertex-transverse presentations) were allocated for vaginal delivery and 27 for cesarean section (18 vertex-breech and nine vertex-transverse). Six pairs of twins in the vaginal delivery group were delivered in a different mode than requested by the protocol (two women underwent cesarean section; in four cases the second twin spontaneously changed to vertex presentation). There were no significant differences between 1- and 5-minute Apgar scores and incidence of neonatal morbidity between the second-born twins in both study groups. Firstborn twins had higher 1-minute Apgar scores than the second-born infants irrespective of route of delivery (p less than 0.05). No case of birth trauma or neonatal death was recorded. Maternal febrile morbidity was significantly higher in the cesarean section group than in the vaginal delivery group (40.7% versus 11.1%, p less than 0.05). These results suggest that in twins with vertex-breech or vertex-transverse presentations after the thirty-fifth week of gestational age the neonatal outcome of the second twin was not significantly influenced by the route of delivery.     

Singleton term breech deliveries in nulliparous and multiparous women: a 5-year experience at the University of Miami/Jackson Memorial Hospital.

OBJECTIVE: The purpose of this retrospective study was to evaluate the feasibility of planned vaginal delivery, the maternal morbidity and mortality, and the short-term perinatal outcome in selected multiethnic women at term with singleton breech presentations. STUDY DESIGN: Singleton breech deliveries were identified from the delivery database between January 1, 1989, and December 31, 1993. A retrospective chart review identified 310 nulliparous and 711 multiparous women at term (37-42 weeks) for a total of 1021. Parameters studied included the success rate of planned vaginal deliveries and the incidences of maternal morbidity, perinatal morbidity, and mortality as a whole stratified by parity and mode of delivery. The Student t test, chi(2) test, and Fisher exact test were used for statistical analysis. RESULTS: Among 1021 women with singleton fetuses in a breech position at term, 191 were candidates for vaginal delivery, and 135 (70.7%) of these deliveries were successful. By parity, 12.3% of 310 nulliparous women and 21.5% of 711 multiparous women were candidates for vaginal delivery; 50% of the former and 75.8% of the latter underwent vaginal delivery. Maternal morbidity was more commonly associated with multiparity and cesarean delivery. Newborn intensive care admissions were equally distributed by parity, and significantly more were for vaginal than cesarean deliveries (17.4% vs 10.8%, P =.036). Premature rupture of the membranes complicated deliveries in 23.9% of the nulliparous women and only 6.5% of the multiparous women (P =.000). CONCLUSION: In this multiethnic population 70.7% of candidates selected for attempted vaginal breech delivery at term were successful. The remaining 29.3% underwent cesarean delivery for labor disorders or nonreassuring fetal heart rate patterns.     

Outcome of twin deliveries at the University Teaching Hospital, Yaoundé, Cameroon-a 15-year experience.

From 1982 to 1996, a total of 16 181 deliveries was registered at the obstetric unit of the Yaoundé University, Cameroon, out of which 291 were twins (1.8%). For the latter, the average gestational age was 37 +/- 2.9 weeks. In 45.0% of cases both fetuses presented cephalic, in 42.6% one presented cephalic and the other breech, while both fetuses presented as breech in 9.9% of cases. The frequency of the combination cephalic-transverse was 0.05%. Spontaneous delivery of both babies was observed in 90.2% of the patients, while in 9.7% delivery of both babies was by caesarian section. The caesarian section rate for a retained second twin was 1%. The perinatal mortality rate was 65 per 1000 (38 deaths in the first week of life), out of which the fetal loss was 4.4% for the first twin compared with 7.9% for the second. The perinatal mortality for the second twin was significantly associated with the type of fetal presentation at the time of delivery, as well as the time gap between the delivery of the twins. Sixteen deaths were observed amongst second twins after podalic presentation out of a total of 23 deaths recorded in the group. In addition, the mortality rate among second twins born more than 20 minutes after expulsion of the first was four times higher than in those delivered within 20 minutes time interval (16.0%5 versus 4.3%). The main cause of twin deaths in our study was found to be prematurity which complicated 30 cases of the registered deaths (78.9%).     

Selected intrapartum external cephalic version of the second twin.

After delivery of twin A, external cephalic version was attempted on 30 malpositioned second twins (12 transverse and 18 breech). Version was successful and resulted in subsequent vertex vaginal delivery for 11 of the 12 transverse presentations and 16 of 18 breech presentations. Successful version was not associated with parity or with birth weight. Among the 30 attempted versions, only one infant had a 1-minute Apgar score below 7. There were not enough cases to determine an association of delivery interval between twins and poor neonatal outcome. External cephalic version in selected twin gestations is useful for management of the second twin with abnormal presentation. Technique refinement and greater experience may improve the overall success rate with external version of the second twin. Although external cephalic version cannot yet be recommended as the method of choice, the procedure seems safe, and routine cesarean delivery may not always be indicated.     

Umbilical cord acid-base state and Apgar score in term breech neonates

Umbilical cord acid-base state and Apgar score were compared in neonates after breech and vertex term birth. The breech group comprised 149 consecutive newborns, 91 born vaginally and 58 by cesarean section. The control group consisted of a random sample of 150 newborns in vertex presentation: 100 born vaginally and 50 by cesarean section. Among vaginally born babies, the 1-min Apgar score was more often depressed in the breech presentation group than in the vertex group; after 5 min the Apgar scores were comparable in both groups. No difference was found in umbilical cord values of pH and base excess between the breech and the vertex groups when comparison was made within each delivery mode. In both groups, umbilical cord values were lower after vaginal than after abdominal delivery. It is concluded that in selected cases, uneventful vaginal breech labor and delivery at term is not associated with an increased risk of asphyxia.     

Mode of delivery for breech presentation in grandmultiparous women.

OBJECTIVES: To compare maternal and neonatal outcomes of planned vaginal delivery vs. elective cesarean delivery for breech presentation at term. METHODS: Retrospective study of term breech deliveries from January 1997 through December 2000. A group of 128 women for whom vaginal delivery was planned was compared with a group of 122 women who had an elective cesarean delivery with regard to neonatal mortality and morbidity (birth trauma, birth asphyxia, hyperbilirubinemia, and duration of stay in the neonatal intensive care unit) and maternal morbidity (infections, hemorrhage, hysterectomy, deep venous thrombosis, and pulmonary embolism). RESULTS: There was no difference in neonatal mortality and morbidity between the two groups (13.0% vs. 9.4%). There were fewer maternal complications in the planned vaginal group than in the elective cesarean group (5.5% vs. 18%; P<0.01). In the planned vaginal delivery group 70% of multiparas and 85% of grandmultiparas were delivered vaginally compared with 50% of nulliparas. CONCLUSIONS: In breech presentations at term vaginal delivery can be achieved in 85% of grandmultiparas without significant neonatal morbidity. Elective cesarean section is associated with increased maternal morbidity compared with planned vaginal delivery.     

Cesarean delivery versus vaginal delivery: impact on survival and morbidity for the breech fetus at the threshold of viability

Objective.?To determine if cesarean delivery is associated with improved survival and morbidity in the breech fetus at the threshold of viability.

Study design.?The Missouri maternally linked cohort data files covering the period 1989 through 2005 were utilized for analysis. All pregnancies with singleton fetuses in the breech presentation delivered between 23⁰ and 24⁶ weeks gestation and birth weights between 400 and 750 g were included. Logistic regression was used to compare cesarean to vaginal delivery after controlling for maternal demographics and pregnancy complications.

Results.?A total of 325 breech singletons were analyzed; cesarean deliveries accounted for 46.1% (150) and vaginal deliveries accounted for 53.9% (175). Cesarean delivery was associated with a survival benefit across all birth weights. Morbidity was higher in cesarean compared to vaginal delivery.

Conclusion.?Although cesarean delivery appears to be associated with an increase in survival at the threshold of viability for the breech fetus, there is a concomitant increase in morbidity. Any benefit that cesarean delivery conveys on survival at the threshold of viability should be weighed against the increased maternal morbidity and high overall neonatal morbidity.     

The premature breech presentation: outcome of newborn infants born by vaginal or abdominal delivery

There is ample documentation that breech full-term infants delivered vaginally have a higher perinatal morbidity and mortality rate than breech infants born via cesarean section. Until now, little emphasis has been placed on the risks to premature newborns born in breech presentation. Therefore, the authors have considered all singleton pregnancies with infants in breech presentation admitted to the Department of Obstetrics, University of Padova, from January 1978 to December 1979 and delivered before 36-weeks gestation. On the basis of obstetric management, the authors have obtained two groups: Group A comprised 36 infants born by vaginal delivery; Group B totaled 32 newborns delivered by cesarean section. Mean gestational age and birthweight were comparable. Of the neonatal events considered, the following were significantly different: Apgar score at 5 minutes less than 7 (A = 30.6%; B = 9.3%), mortality (A = 13.8%; B = 0), neurologic sequelae in the infants discharged from the neonatal intensive care unit (NICU) (A = 50%; B = 9.1%) and the sum of mortality and long term sequelae (A = 22.2%; B = 3.1%). The authors conclude that cesarean section performed in mothers with impending preterm breech delivery decreases the neonatal mortality rate and improves the long-term outcome.