Cesarean section once performed, paves the way for a repeat cesarean often, which in turn results in multiple disadvantages. An attempt is made to view the place of vaginal birth after cesarean against the consequences of not giving such a trial and choosing to perform a repeat cesarean section. The aftermath and repercussions of a previous cesarean section on future obstetric and gynecological outcomes are hereby presented.
The adherent bladder can pose multiple problems in future pregnancies or in any type of hysterectomy. The increasing incidences of Cesarean sections multiplies these problems.
The prevalence of cesarean delivery (CD) is high in many parts of the world, more so in private practice. In the United States it is at a record high of 31.1% of all births, representing an increase of 50% in the past decade 1. In certain emerging economies, such as Brazil, CD rates, exceed 75% in the urban private sector 2. In Brazil there are hospitals with cesarean section (CS) rates of 100% and some health districts with an 85% CS rate. In Sweden, Denmark and Netherlands the CS rate is close to 10% with one of the world’s lowest maternal and perinatal morbidity and mortality rates 3. Approximately 12% deliveries are estimated to occur by CD in he developing world – as low as 8% if births in China are excluded 4. The World Health Organization (WHO) advocates an “optimal” national CD rate between 5% and 15% of all births, which suggests that levels less than 5% sometimes a indicates limited availability of cesarean facility for the rural and the poor of the world. Cesarean section rate in rural areas of Tanzania is 5% and 1.5 to 2.3% in Madagascar 5.
Between 1989 and 1996 the total cesarean rate decreased due to a decrease in the primary CS rate and an increase in the rate of vaginal birth after cesarean (VBAC). Since 1996, these trends have reversed, and increases have been rapid and sustained for primary CS and repeat cesarean with a decrease in the VBAC rate from 28.3% to 9.2% and a corresponding increase in the repeat cesarean rate to 91% in 2004 6. In the 1980s, the dictum “once a cesarean, always a cesarean,” espoused by Craigin in 1916, was revised in many countries, so as to reduce cesarean section rates.
Is the increase of CS the result of changes in physician practice methodology regarding cesarean delivery, due to increase in maternal requests for cesarean section, or a combination of the two ? Is the overall increase in the cesarean rate the result of an increase in elective cesarean sections? What are the advantages and disadvantages of cesarean delivery for mothers and neonates? The Myth and Reality Incision choice.
The Pfannenstiel incision is a most commonly used incision in women having a first CS and is also used in case a repeat a CS is required. However some obstetricians believe that a vertical midline sub umbilical incision (MSU) prevents bladder and bowel inquires.
In a series of 3164 women having repeat CS between 1999-2003 in women with cesarean deliveries 86% had Pfannenstiel incision and 14% had MSU, bladder and bowel injuries were seen more in cases where are MSU were done than with Pfannenstiel incision Pfannenstiel incision is stronger, less painful and with respiratory movements causes less pain than a midline incision 7. A Pfannenstiel incision is often the best choice for a primary and or a repeat C.S. A MSU incision should be used only for compelling reasons.
Misgav Ladach and Joel Cohen incisions at cesarean delivery do not provide advantages at future obstetric or gynecological interventions. Exteriorization, of the uterus during suturing remains a presonal choice in the absence of any convincing data to either way as per a systemic Cochrane review 7-9.
Lower segment transverse incision is the choicest transversal expansion. Women with previous low vertical uterine incision were just as likely to have successful VBAC as women with a previous low transverse uterine incision 10. Classical cesarean scar has a rate of uterine rupture in future pregnancies of 4% to 9% and is even higher in some areas.
There is virtually no role today for a classical C.S. except in some conditions. However it is prudent to perform a tubal ligation whenever this method is appropriated.
In patients where the parietal peritoneum was sutured at the first Cesarean Section there were fewer adhesions compared to those in whom the primary peritoneum was not sutured in the same setting(73%). This non randomized study raises questions about the practice of not suturing the parietal peritoneum at Cesarean delivery. A controlled study showed that in those patients similar to the 73% described, there was an increased time taken to make the uterine incision due to adhesions in repeat Cesarean Sections as well as a longer operating time and an increase post operative analgesia. The National epidemiology unit at Oxford University is co-ordinating a multicentric trial of Cesarean Delivery techniques, the “Cesarean Rate study” concerning some aspects of C S eg a single or a double layer closure of the uterine incision, non closure of the parietal peritoneum and the usage of abdominal drains. However a review of literature including animal experiments, general surgery outcomes and gynaecological data encourages one to omit peritoneal closure 13.
The incidence of ventral hernia in patients with the vertical midline incision is 10% to 16%. The Smead Jones technique of interrupted closure when compared with the non locking continuous technique of closure of a vertical midline laparotomy incision found no difference in the incidence of a ventral hernia resulting , though the incidence of a burst abdomen got reduced to 50% when the technique of interrupted sutures was used. Ninety percent hernia occur within the first year of surgery. Risk for herniation includes BMI> 27,diabetes and wound infection. A single Pfannenstial incision has a very low incidence of hernia occurring 11 15.
Can an incisional hernia be repaired at the time of repeat CS?. If a future pregnancy is desired it is not advisable. However, if not, it is worth repairing the hernia meticulously using special suturing material and not a mesh as an infection may result in severe complication and, necessitate removal.
Women with a prior history of one uncomplicated lower- segment transverse cesarean section, in an otherwise uncomplicated pregnancy at term, with no other contraindication to vaginal birth, should be able to discuss the option of planned VBAC or the alternative of a elective repeat cesarean section(ERCS).
Based on retrospective cohort studies, most women with one previous low-transverse cesarean delivery are candidates for vaginal birth and should be counseled and offered a trial of labor 10,16. Women considering their options for delivery after a single previous cesarean should be informed that, while the chance of successful planned VBAC are 72-76% planned VBAC carries a risk of uterine rupture of 22-74/10,000. There is virtually no risk of uterine rupture in women undergoing ERCS.
A meta-analysis of articles published in the period 1982- 1989 failed to identify advantages for elective repeat cesarean delivery, compared with trial of labor, with regard to uterine rupture and perinatal death, in contrast, a meta-analysis published from 1989 to 1999 with a higher rate of uterine rupture and perinatal death following a trial of labor than following elective cesarean section 17,18.
In a retrospective, population based review in Washington state USA a total of 20095 cases with a history of low transverse cesarean for first delivery, gave birth to a second child (1987 through 1996). The risk of rupture was compared amongst women who had repeat CD, vaginal deliveries following the spontaneous onset of labor and labor induced with or without prostaglandins. Rupture rate per 1000 varied from 1.6 in women with repeat CD, 5.2 with spontaneous labor and vaginal delivery and 7.7 when labor was induced without PG and 24.5 when induced with PG 19.
Uterine injury occurs in 1.3% and 0.4% of women undergoing TOL and ERCS, respectively, and the risk of uterine lesions is 3-fold greater in patients planning VBAC, compared with those undergoing ERCS. Additional intervention, in particular blood transfusion and hysterectomy, are seen with the same frequency in the two groups 20. Four findings were supported by moderate level evidence. Medically elective cesarean delivery (compared with the combination of planned VBAC followed by emergency cesarean delivery) was associated with : (1) a decreased risk for maternal hemorrhage; (2) an increased risk for respiratory problems for infants; (3) greater complications in subsequent pregnancies, including uterine rupture and placental implantation problems, and (4) longer maternal hospital stay 21. Further comparison and analysis vis a vis failed vs. successful VBAC and ERCS, showed that women with VBA failure have an increased risk of maternal adverse outcomes compared with both latter groups. In particular, when a TOL fails, maternal morbidity is 17%, which is much higher than 3.1% assessed in women with a successful vaginal delivery.
Uterine lesions are also observed more often following a failed TOL (4.4%), in contrast to a successful VBAC (0.2%), and this finding might explain why blood transfusion and hysterectomy are more often required in the former than the latter group. Because the increased maternal morbidity in women attempting a TOL is primarily detected when TOL fails, it is mandatory identify factors associated with failed TOL prior to selecting patients as VBAC candidates. Therefore, many studies have focused on risk or predictive factors of unsuccessful VBAC. History of a previous spontaneous vaginal delivery before the initial cesarean delivery is an excellent favourable predictor for successful TOL.
In a global study of the relationship between method of delivery and maternal and neonatal mortality, found that for countries with overall caesarean rates below 15%, higher cesarean rates were correlated with lower maternal morality. For countries with national cesarean rates above 15%, however, “higher cesarean rates are predominantly correlated with higher maternal mortality. A similar pattern is found for infant and neonatal mortality 22.
Women considering planned VBAC should be informed that this decision carries a 2-3/10,000 additional risk, of birth-related perinatal deaths when compared with ERCS. The absolute risk of such birth-related perinatal loss is comparable to the risk for women having their first birth. MacDorman and colleagues examined neonatal mortality using linked birth and infant death certificate data for 1998 to 2001 from 5.7 million births with NIR for cesarean delivery. They found that even in the most conservative model (excluding congenital anomalies and Apgar scores less than 4 and adjusting for socio-demographic and medical risk factors), the odds ratio for neonatal mortality for primary caesarean delivery was 1.73 compared with 0.72 by vaginal delivery.
A large study in Latin America showed cesarean section has not necessarily improved perinatal outcome contrary to data from developed countries 23. Elective cesarean delivery was associated with greater respiratory morbidity, higher NICU admissions, greater hospital stay and increased risk of complications in subsequent pregnancies, when compared with planned vaginal delivery. No wonder, ACOG recommends for elective cesarean delivery on maternal request (CDMR)when performed, the estimated gestational age should be at least 39 weeks or lung maturity should be confirmed. Elective CD before 39 weeks will have much greater morbidity 24.
Although comparisons are limited by differences in methodology between various studies, there seems to be more evidence now than at the time of the National Institute of Health (NIH) conference for an increased risk for maternal and neonatal mortality and morbidity for medically elective caesareans compared with vaginal births. In addition, the increase in the primary cesarean rate seems primarily the result of changes in obstetric practice and not due to changes in the medical risk profile of births or increases in maternal request 21.
Despite previous cesarean sections at times the intra- operative scenario may reveal no stigmata of previous surgery or disproportionately there may be severe adhesions following single previous cesarean section.
In a study of 1240 CS with 287 repeat CS, there was abdominal cicatrisation in 24.3% and some adhesions between various intraperitoneal structures in 25.4%, these were the chief causes of difficulties at surgery. This resulted in inaccessibility to the lower segment in 4.5%, bladder injury in 2 cases and extensive ventrofixation of uterus causing an entry in to the uterine cavity in 1 case. Senior obstetricians had to intervene in difficult situations in 5.9% of cases emphasizing the importance of involving seniors in such surgical procedure 25.
It is he least frequent complication in the early postoperative period 26. This had to be performed in 18 (0.53%) out of 3380 cases in Israel between 1996-2006.
Relaparotomy was required because of hemorrhage in 12 cases; eventration in 3 and intrabdominal abscess in 3.
For a successful VBAC trial, ACOG recommends following:
In practice it is important 30 to provide experience based skill, competence and evidence based services to women. Trial of scar (more often called trial of labour) has to be carefully supervised, a second opinion may be sought and ultimately targeted for a 10-15% cesarean section rate and not beyond 20%.
History of CS in past for dystocia is quite helpful as CS performed after full dilatation has poor success rate of 13% in contrast to 67-73% success if CS is performed before complete dilatation eg between 5-9 cms.
Study from California hospitals, of 40000 trial cases gives a 61.4% success rate with a 50-80% success in cases with dystocia and 75-86% success with a non recurring indication of CS in past. CS in the past for dystocia needs an enquiry into the weight of baby, a reason for CS for the current pregnancy an estimated fetal weight and above all the center and / or the individual in charge during the previous cesarean delivery 10. Heredity accounts for 28% of the risk of developing dystocia. Cesarean delivery for cephalopelvic disproportion was associated with a 2 fold increased risk for the daughter having a similar CD and cesarean for dysfunctional labour increased the risk 6 fold for a similar delivery by a daughter 31.
How should women with a previous caesarean birth be advised in relation to induction of labour or augmentation ?
Women should be informed of the two-to three-fold increased risk of uterine rupture and around 1.5 fold increased risk of cesarean section in induced and/or augmented labors compared with spontaneous labours. Oxytocin augmentation study in 1072 patients resulted in a rupture rate of 1% whereas with a spontaneous labor the rate was 0.4% 10.
Risk of uterine rupture is much higher in cases of induction of labor with prostaglandins and therefore discourages PG for ripening or induction in previous CS 10. Interestingly, the Royal College of Obstetricians and Gynaecologists state that in the case of TOL in women with prior cesarean delivery, vaginal prostaglandins appear to be safe 32.
The decision to induce, the method chosen the decision to augment with oxytocin, the time intervals for serial vaginal examination and the selected parameters of progress that would necessitate discontinuing VBAC should be discussed with the patient by the consultant obstetrician.
There should be careful serial cervical assessments,preferably by the same person, for both augmented and non-augmented labors, to ensure that there is adequate cervicometric progress, thereby allowing the planned VBAC to continue.
For a clinical question: should women who have had a previous low-transverse cesarean delivery and who require induction of labor be offered a trial of labor? Evidence based answer is: There are no randomized controlled trials (RCTs) of labor induction in women with a low transverse uterine scar. Although induction in these patients is common practice in other countries, based on these data, the American College of Obstetricians and Gynecologists (ACOG) recommends that patiens be discouraged from induction of labor after a single previous low-transverse cesarean delivery. Rupture risk increases after preinduction cervical ripening and is without risk benefit ratio favouring its use.
A study showed that using oxytocin to augment labor in women with a previous low transverse cesarean delivery increased the risk of uterine rupture compared with spontaneous labor (8.7 versus 3.6 per 1,000); using oxytocin alone to induce labor incrases the risk to 10.7 per 1,000. In women undergoing a trial of labor, the overall uterine ruptue – related perinatal death was 0.11 per 1,000. The rate of perinatal hypoxic brain injury was
0.46 per 1,000 trials of labor compared with zero in women who had a repeat cesarean delivery. Kayani and Alfirevic observed that of 107 women with previous cesarean section but with history of previous vaginal delivery induction of labor were successful in a subsequent pregnancy in 83% of cases, compared with 41% of women without experience of a previous vaginal delivery 10,19.
Two or more previous CS: Risk of rupture is 5 times greater for 2 previous cesarean deliveries compared with 1 CD in past. Risk is 1-3.7%. Women with previous vaginal delivery followed by CD were approximately 25% likely to sustain a rupture during trial of scar. Therefore in women with two previous cesarean sections only those with a prior VD should be considered for spontaneous trial of scar 10. Repeat elective cesarean section performed after 2 cesarean sections in past, is acceptable as normal practice.
Women with a prior history of two uncomplicated low transverse cesarean sections, in an otherwise uncomplicated pregnancy at term, with no contraindication for vaginal birth, who have been fullyinformed by a consultant obstetrician, may be considered suitable for planned VBAC. Success rate of VBAC after 2 or more CS is 71-72% 33. Interestingly a 79% rate of vaginal delivery rate is noted even with history of three or more previous cesarean section 34. However a decision to allow any woman for a VBAC trial after more than one previous section needs to be based on outcome of a bigger metanalytic study. Experienced dedicated obstetricians with the “will” to give the patient a fair chance, in the absence of unfavourable findings and in an ideal setting can undertake a trial for a VBAC after 2 previous CS.
Five or more CS was associated with greater operating time and increased rate of severe adhesions. Interestingly, the higher order 5 to 9 repeat CS carry no specific additional risk for mother or baby when compared with the lower order, 3 or 4 CS 35.
Of five hundred ten women attempting TOL, 66% had successful VBAC and 34% needed repeat CS 29. Greatest success of VBAC was in underweight women (BMI<19.8) 84.7% compared average weight for height with women where the success was 70.5%. BMI>30 had 3 times chance of cesarean section than with BMI of 20 or less 19. Increased CS rate obese women is associated with post-operative complications like wound infection, excessive blood loss and endometritis 29. Thus obesity can be associated with failure of TOL and increased maternal and perinatal morbidity. However a 66% success rate of VBAC in obese women is adequate to allow select patients a chance for a successful VBAC.
Gestation beyond 40 weeks: Induction in these cases was associated with increase risk of rupture. Strict clinical guidelines including the introduction of colour coded partogrm is associated with decrease of rupture risk from 0.42% to 0.27% 36.
With birth weight > 4000 Gms to 4500 Gms, 60-90% women were successful at having VBAC. Ruptue incrased only in those with a previous CS but without previous a VD 10. The moot question is as to whether the head will pass through the pelvis and whether the scar will stand the strain labor or not ?
A cautious approach is advised when considering planned VBAC in women with twin gestation, fetal macrosomia and short interdelivery interval, as there is uncertainty in the safety and efficacy of planned VBAC in such situations.
Rates of successful VBAC and uterine rupture did not differ significantly in studies concerning twin study groups and women with a singleton pregnancy attempting VBAC 10.
No systematic, well-designed data exist on CDMR. However the rate of primary cesareans is increasing and studies using hospital discharge data or birth certificate data estimate that from 3% to 7% of all deliveries and women without prior cesareans have no reported medical or obstetric indications for their primary cesarean deliveries.
Until more information is gathered about CDMRs and until practice standards and guidelines are implemented, an explicitly executed informed consent should form the framework far any decision regarding the mode of delivery. Risk of still births (SB) is increased in women previously having CS. Cefalo comments “women planning a patient choice cesarean delivery should be advised of the possibility of an unexplained SB in a future pregnancy 37,38.
CD still account of 10% of all maternal deaths. A complicated but relevant and timely cesarean delivery on maternal request (CDMR) is defined as a cesarean delivery for a singleton pregnancy on maternal request t term in the absence of medical or obstetrical indications 39. Harer opines that we should tell patients the facts and let them make the choice. He further says “Those who care for patients must consider factors beyond the mechanics of delivering their babies”40.
The most recent national statistics estimates that in 2006, over 30% or 1.3 million births were via cesarean, a national record, and an estimated 2.5% of all births in United States were CDMR 41. CDMR may be responsible for the highest CS rate of 29%. CDMR is low in Spain, France and Netherlands and high in Sweden, Italy,
Luxemburg, Germany and UK 3,42. Interestingly a survey revealed that male physician respondents were significantly more likely than females to agree to perform cesarean delivery and respondents were more likely to agree with a request from a high socio economical strata39.
If the physician believes that cesarean delivery promotes the overall health and welfare of the woman and her fetus more than vaginal birth, he or she is justified in performing a cesarean delivery. However, available evidence is that normal vaginal delivery is safer in the short and long term for both mother and child.
In contrast, the International Federation of Gynecology and Obstetrics (FIGO) states 43. At present, because hard evidence of net benefit does not exist, performing cesarean section for non-medical reasons is not ethically justified.
Zaki et al reported 60% rate of placenta accrete with 3 or more cesarean deliveries 47. Prenatal Ultrasonography, MRI and color Doppler are useful to define an abnormally implanted placenta. Therefore, it is necessary to counsel such patients about possible blood transfusions being required the choice of blood products being required and possible hysterectomy. In 27000 attempted trial of scar after CS in past, for VBAC there were 3 maternal deaths.
Speculum examination shows the cervix is inaccessible or barely visible on speculum examination with stretched and pulled up posterior vaginal wall. Traction on the cervix, with some difficulty, will not bring the cervix fully into view but pulls the lower abdominal wall inward. Unseen cervix is almost behind pubic symphysis under anaesthesia.
Often, a history of CS in past makes a gynecologist to not choose the vaginal route for a hysterectomy. In absence of any contraindication, woman needing hysterectomy, is therefore subjected to more invasive abdominal or LAVH / LH, which may be easier for gynecologist but less desirable for the patient as compared to vaginal hysterectomy. Apprehensions that prevents a gynecologist from attempting a vaginal hysterectomy in these patients include the fear of bladder trauma and/or access to vesicouterine peritoneum.
Carpenter and Silva compared abdominal and vaginal hysterectomy cases after previous pelvic surgery and concluded that “vaginal hysterectomy following pelvic operation is technically easy and without increase in morbidity’. Kovac recommends LAVH to access vesicouterine peritoneum and perform hysterectomy in such cases 50. Sizzi and Rossetti 51 laparoscopic surgeons advocate that the best method is to access the vesico uterine peritorum from lateral surgical window or utero- cervical broad ligament space. Bladder as a rule is adherent in the central three fifths with the lateral one fifth free. The same approach is utilized by laparoscopic surgeons at laparoscopic hysterectomy, and the same approach holds true at abdominal hysterectomy when bladder is adherent after previous cesarean section.
For a patient with one or more vertical abdominal incisions for cesarean section past opening the abdomen again to perform a hysterectomy markedly increased the patients chances of developing an incisional hernia. It is best is to perform hysterectomy via vaginal route, if not contraindicated. If contraindicated, an abdominal Pfannenstiel’s incision can be used.
