A woman was being supervised in her second pregnancy in our antenatal clinic. In her first pregnancy two and a half years back, a caesarean section had been performed for foetal distress during labour at term at a private nursing home. The baby had weighed 2.8 kg and was doing well. The caesarean operation and the postoperative recovery were uneventful. In the present pregnancy, there were no comorbidities or any complications. The foetus was in left occipito-anterior position, and the estimated birth weight was 2.7 kg. The pelvis was normal. She was willing for the trial of labour (TOLAC), and so we waited for spontaneous labour. The woman came back in spontaneous labour and was admitted in active labour. At admission, her pulse rate was 84/min with normal blood pressure. Abdomen revealed single-term foetus in left occipito-anterior position with regular good uterine contractions. The foetal heart trace was good. Vaginal examination confirmed 4 cm dilatation with full effacement and clear liquor draining. The pelvis was adequate, and the vertex was at -2 station. Two hours later she suddenly developed tachycardia with foetal bradycardia. The cervix was 6 cm and vertex was at -1 station, but the liquor was meconium stained. She was taken up for immediate caesarean section; there was full-thickness full-length scar rupture (Fig. 2.2). We delivered an asphyxiated 2.8 kg foetus from within the uterus. The rent was repaired.

The baby died in the NICU after 24 h. I felt miserable about the decision. Later I got to know that in that nursing home as a matter of routine, caesareans were performed by surgeons who would close uterus in single-layer locking sutures. Over a period, we have learnt lessons by facing the mishaps of rupture and scar dehiscence. We have identified the hospitals and the nursing homes surrounding our hospital whose caesarean scars have failed to withstand labour. We no longer post the women who underwent caesareans in these hospitals for TOLAC. It is a cause of great concern as there is an increase in the rate of repeat caesareans for fear of rupture. It is the moral and ethical duty of those who perform primary caesareans to follow the scientific techniques of repairing the incision and documenting the same properly in the discharge slips.

The commonest reason for concern suspecting the integrity of the scar is maternal tachycardia. However, there may be situations when one may take the decision to deliver by caesarean due to maternal tachycardia only to find a healthy intact previous scar. It is, therefore, important to give adequate pain relief and keep her well hydrated to prevent tachycardia due to other reasons confusing the picture.

Pain in the suprapubic region is another symptom of concern and might be one of the reasons for performing an emergency caesarean section. Cohen and colleagues [13] observed that abdominal pain alone is a poor predictor of scar rupture, but in the presence of an additional symptom or sign, it has a nearly 60 % positive predictive value for rupture.

It is also commonplace to find foetal heart rate abnormalities as the most important and only manifestation of scar dehiscence. Quite often during monitoring, one finds foetal tachycardia, variable deceleration, or bradycardia in a labouring woman with a previous caesarean scar.

In a population-based case-control study among women with previous caesarean section undergoing a trial of labour, Andersen and co-authors [5] observed that 77. 5 % of women with rupture had pathological (cardiotocography) CTG in early labour. Foetal tachycardia was significantly higher in women with scar rupture than in controls (OR = 2.5). Severe recurrent variable decelerations were also found to predict rupture.

In a large multicenter case-control study [16], the authors observed that grade 3 foetal heart abnormalities (as defined by the FIGO guidelines [17]), in a woman with a previous caesarean scar in labour, are significantly likely to be associated with scar dehiscence, with an odds ratio of 4.1. It is important to view the foetal heart rate abnormality seriously and consider termination by caesarean section instead of an overenthusiastic attempt at resuscitation and continuing the trial because though the foetal heart rate may transiently recover, it may present a little later as a florid rupture where the risk of losing the baby increases many times. In this regard, the American [1] Royal College of Obstetrics and Gynaecology [36] and the Canadian Society [44] have recommended the use of continuous electronic foetal heart rate monitoring in women undergoing a trial of labour after previous caesarean section.

The other manifestation of scar dehiscence during labour is bleeding from the vagina. Typically it may not be excessive. Sometimes it may be perceived as the excessive show. Patients with abruption may further confuse the picture. That brings me to this case. A woman presented at 34 weeks of pregnancy with acute onset bleeding. It was the first episode associated with diffuse abdominal pain. There was a loss of foetal movements. She was in her second pregnancy and had one live issue. Previous was a caesarean section done in a private hospital for foetal distress. On examination she was pale. The pulse rate was 110/min. The blood pressure was 100/60 mm of Hg. The abdomen revealed a 36-week size uterus that was tense and tender. The foetal heart sound was absent. The uterine contour was made out, and the uterus was contracting. There was haematuria. Scar rupture was a close differential diagnosis, but because of the uterus acting and relaxing, it was less likely. On pelvic examination the cervix was 2 cm; 50 % effaced, membranes were present with the vertex at -3 station. Artificial rupture of membranes confirmed blood-stained liquor. Thus, the working diagnosis was grade IIIb abruption. The labour was augmented with low-dose oxytocin, and parallel resuscitation and correction of coagulation failure were carried out. Thus, it is very important to understand that even though there may be maternal tachycardia, bleeding, foetal demise, and haematuria in a woman with previous caesarean section, other causes like abruption could be an underlying feature, and the fact that uterus is contracting and relaxing may be the only feature against scar dehiscence.

She eventually delivered, but there was a continuous trickle of bleed with the uterus having a tendency to relax. The scar appeared thinned at digital exploration. Given continued postpartum haemorrhage and suspected scar integrity, she was taken up for laparotomy. Strangely the whole lower segment was bruised (Fig. 2.3).

There was couvelaire uterus. The utero-vesical fold was opened. The bruised lower segment was freshened and sutured. She recovered well. Whether the bruising was a manifestation of coagulation failure or impending rupture is a debatable issue.

A woman presented in labour at term. Her previous delivery was by lower segment caesarean section 3 years back for non-progress of labour in a government hospital. It was a 3 kg baby. The postoperative period was uneventful. At the time of admission, the pulse rate was 84/min. There was a single foetus in right occipito-anterior position palpable three-fifths above the brim. The expected foetal weight was 2.7 kg. The contractions were regular and moderate. Vaginal examination revealed 4 cm dilated fully effaced well-applied cervix. The clear amniotic fluid was draining, and membranes were absent. The position was confirmed as ROA and the station was -2. The pelvis was normal. She was monitored closely for the progress of labour. The foetal heart rate was well preserved with good variability and no decelerations. Two hours later the contractions seemed to become less intense and regular. The frequency reduced to once in 4 min and would last only 25 s. There was no maternal tachycardia. Foetal heart trace was good. Vaginal examination revealed a protracted dilation and descent. Labour was augmented with low-dose oxytocin drip. The contractions transiently improved in intensity but became erratic with few contractions lacking the intensity and remaining ill-sustained. Labour augmentation was continued while the woman and the foetus were carefully monitored. The foetal heart trace was well preserved; there was no maternal tachycardia or bleeding from the vagina. After 2 h vaginal examination revealed arrested dilation and descent, and so the decision for termination by caesarean section was taken. There was scar rupture of 1 cm length at the right end with the loss of all the layers and the foetal head seen through (Fig. 2.4). The foetus was delivered in good condition, and the rent was repaired. The recovery was uneventful.

I wonder if there was any further prolongation, there might have been a full-blown rupture affecting the foetal outcome. It is extremely important to be vigilant about the changing patterns of uterine contractions in a woman with previous caesarean scars. In the above case, there was no maternal tachycardia or bleeding or foetal heart rate abnormities. Any incoordinate uterine contractions or tendency for secondary inertia might be the only subtle sign of early dehiscence as in this case.

Thus, diligent monitoring of various possible manifestations (Box 2.1) of a scar giving way is very important during the first stage of labour.

The second stage is a particularly testing period for the strength of the scar. For this reason, some authors [22] have advocated forceps delivery to cut short the second stage of labour.

I have come across many cases where caesarean was decided for the non-descent of the head with deceleration even in the second stage to realize that there was scar dehiscence at the time of caesarean delivery.

This particular case I now narrate is just to discourage heroic decisions. A 28-year-old second gravida was supervised from the early pregnancy. She had undergone a caesarean 3 years back in our hospital for foetal distress to deliver a 3 kg baby. The records confirmed an uneventful lower segment caesarean section, and the incision had been closed in two layers. The postpartum recovery was uneventful. In the ongoing pregnancy, there were no comorbidities. She crossed her dates and would not go into labour. It was a 3.5 kg expected birth weight. The pelvis was normal and adequate. The foetus was in occipito-transverse position at -3 station. In an attempt to reduce the caesarean section rate, it was decided to induce labour as everything was conducive and the woman was willing for TOLAC. The cervix was ripened with Foleys catheter bulb. Labour was induced with a low dose of oxytocin. Active labour got established though it became slightly protracted. Labour augmentation was continued with oxytocin in spite of the protracted labour. The foetal heart was well preserved, and the liquor was clear. She achieved the second stage. There was an arrest of descent of the head beyond +1 station even after 1 h of being in the second stage. Foetal bradycardia was noticed, and she was taken up for caesarean section. There was a full-thickness scar rupture. A 3.75 kg stillborn foetus was extracted, and the uterus was repaired. It is prudent to consider elective caesarean section if the baby weight is on the higher side. As I already brought out, the other important though subtle signals we need to be watchful about are protracted labour, after she has achieved active labour especially so with a baby weight on the higher side. In a nested case-control study by Harper et al. [23], the authors observed that women who had scar rupture or failed TOLAC had protracted progress after 7 cm dilation.

Scar rupture at the second stage may have varied presentations. I came across an extremely interesting case. A woman with previous caesarean section presented to the hospital in labour. She was found to have severe preeclampsia. The previous caesarean was done 2 years back for a nonrecurring indication. At the time of admission, she was not pale. The blood pressure was 160/ 100 mm of Hg. She was 4 cm dilated with good foetal heart sounds and a 2.5 kg expected baby weight. Artificial rupture of membranes revealed clear liquor. The labour progressed well, and she delivered a 2.6 kg baby uneventfully spontaneously after 4 h of admission. There was no postpartum haemorrhage. The blood pressure settled.

After 12–14 h of delivery, she developed mild abdominal distension and pain. The pulse rate was 100 per minute. She did not appear pale. The blood pressure was 130/80 mm of Hg. The abdomen was mildly distended and tender but not guarded. Urine was mildly high coloured, and output was around 40 ml per hour. We observed the patient and infused fluids. Sonography revealed slight free fluid in the abdomen, but all other organs were normal. There was no bowel dilatation observed. The uterus was puerperal with an empty cavity. The abdominal girth slowly increased, and she developed tachypnoea. Abdominal paracentesis revealed haemoperitoneum. At laparotomy, there was a complete full-length scar rupture. The edges had retracted, and there was slow ooze from the edges. The presentation could be as indolent as this with a good perinatal outcome.

In yet another case, I was called by the registrar from the family planning operation theatre. She was doing puerperal sterilization for a woman who had a successful, uneventful vaginal birth after caesarean section (VBAC) 2 days ago with us in the hospital. The registrar suspected something wrong because haemoperitoneum showed up even on opening the abdomen by mini-laparotomy incision. On extending the abdominal incision, a full-length complete rupture became evident; the margins had nearly stopped oozing on their own. The same was easily repaired. How lucky are a few patients and how varied is the presentation of scar rupture that follows delivery of the foetus!

As illustrated by the above two cases, the scar can rupture late in the second stage and have an indolent presentation where fortunately both mother and foetus escape serious harm. However, continued monitoring in the postoperative period would reveal slowly developing symptoms and signs. A high index of suspicion is necessary especially because the foetus is born alive and the mother does not exsanguinate herself. Sometimes I wonder how many patients like this must have escaped notice and intervention and gone home and healed the small rents on their own. It is also possible that such cases that go home with the dehiscence unnoticed after successful vaginal delivery come back after a few days with puerperal sepsis and peritonitis if infection supervened and interfered with the healing as illustrated by a case later.

That brings me to the controversy of whether to explore the scar routinely after delivery. The answer is difficult, and it should be reserved only for cases with excessive bleed or other signs suggestive of scar rupture. Perrotin and colleagues [34] recommended that the exploration of the scar should be done in symptomatic patients only. The Canadian [44] as well as RCOG [36] guidelines also recommend the same.

A defect may feel like a full-thickness defect or a breach of the mucosa and inner layers only, under an intact serosa.

I would like to narrate a few more situations I came across. A woman had a successful VBAC and delivered a healthy luscious baby spontaneously, but had postpartum haemorrhage (PPH). The brisk bleeding compelled an immediate laparotomy. There was full-thickness scar rupture. The right edge of the rupture had involved the uterine artery and hence the brisk bleed. Of course, this patient was managed by suturing the rent, and she consented for sterilization also.

In yet another case, the woman delivered uneventfully. The bleeding appeared slightly excessive. Scar was explored and a rent suspected. Full bladder abdominal and a transvaginal scan confirmed the diagnosis. There was a discontinuity of the lower segment (Fig. 2.5).

Since the patient was stable and not anaemic, she was managed conservatively with antibiotics and monitoring for any deterioration. She recovered uneventfully and was discharged on the 14th day with the advice for interval sterilization and the need to avoid future pregnancies.

The patient’s condition started deteriorating in spite of antibiotics after 48 h with fever spikes persisting and the abdominal fluid collection increasing. She developed tachypnoea and dyspnea, and the oxygen saturation started dropping and so exploratory laparotomy was carried out. There was pus in the peritoneal cavity and full-thickness scar rupture with friable and oedematous margins of the lower segment. The same was repaired. Peritoneal lavage was done, and a drain was inserted. It is possible that the scar must have given way at the second stage without affecting the perinatal outcome. The scar must have got infected due to ascending infection eventually causing peritonitis and deterioration. The woman was not immune-compromised or diabetic. The vagina would have been infected with Candida which was not recognized or treated before delivery resulting in such a florid infection of the ruptured scar. A similar case was reported way back in 2005 by Sun and colleagues [46]. However, it was an unscarred uterine dehiscence. She had presented 20 days after the successful vaginal delivery. The authors managed her with laparoscopic repair.

In yet another interesting presentation [32], the woman was found to have omentum protruding from the vagina in the fourth stage of labour after she had a successful VBAC.

Thus, the scar integrity is put to test throughout labour and needs careful monitoring for the various signs alerting a possible dehiscence right from the onset of labour till 48 h or so after delivery.

Box 2.2 summarizes the features that are likely to raise suspicion of scar rupture in the second stage.

Though the American and UK College recommend a trial of labour in a woman with previous two caesarean sections, one has to be very cautious. As a policy in our country, we prefer elective caesarean delivery for a woman with previous two caesarean sections. There have been instances where a woman with previous two caesareans came late in labour and delivered uneventfully.