**2. Data collection**

We did a systematic literature review of PubMed and the Cochrane Database. Search terms used were multiple cesarean section, repeat cesarean delivery, maternal morbidity, neonatal morbidity, maternal and fetal outcome of multiple cesarean section, bladder injury, uterine scar rupture, placenta increta/percreta, hysterectomy, hemorrhage and transfusion, adhesions after repeat cesarean section, vaginal birth after cesarean section, VBAC after cesarean section, and timing of repeat cesarean delivery.

Prior to beginning the search, we defined inclusion and exclusion criteria. Inclusion criteria were randomized controlled trials, cohort studies, case–control studies, systematic reviews, meta-analysis, and the above search terms. Exclusion criteria were comments, letters to the editor, personal communications, and case reports.

The authors selected the articles first through focused review of the abstracts. Eligible studies underwent full text review. We identified a total of 2190 studies of which 1999 were excluded for not meeting either the inclusion criteria or exclusion criteria or for not answering the research question.

A total of 38 studies and 2 Cochrane systematic reviews ranging from 2005 to 2018 were included in the final analysis. All manuscripts were retrieved in electronic PDF format and analyzed in detail.

The references of the most important studies were again checked for eligibility as part of the search strategy. Data from the randomized controlled retrospective trials and Cochrane systematic reviews were extracted by topic, and data were grouped and reanalyzed.

Thus, the result of this chapter is a review of the safety and risks associated with multiple repeat cesarean section for both the mother and the baby. This can be helpful for the counseling of parents and the decision-making of the mode of delivery.

### **3. Maternal risks**

The results of the most important maternal risks of multiple repeat cesarean sections are summarized (**Table 1**). In total eight studies were eligible and were included in this review. Furthermore, each one of the risks is discussed in detail.

The results of **Table 1** demonstrate that the frequency of bowel and bladder injury is about 0.1% with up to three previous cesarean sections and just under 1% thereafter [3–7]. Uterine rupture is <1% up to two cesarean sections but increases thereafter to about 4%. Blood transfusions are common and required in up to 5%. Intensive care does not increase substantially and is less than 2% (and may also be due to underlying diseases). Hysterectomy and placenta accreta are less than 1% for up to three cesarean sections but 2.5–3% in more than four. Severe adhesions are already common in more than one cesarean section.

**39**

*Maternal and Fetal Risks in Higher Multiple Cesarean Deliveries*

n = 6/6616 [5, 8, 10, 11]

n = 6/6616 [5, 8, 10, 11]

n = 126/28,810 [8, 12]

n = 261/6443 [5, 10, 11]

n = 127/6374 [3, 8, 10, 11]

0.69% n = 44/6374 [3, 8, 10, 11]

n = 46/6374 [8, 10, 11]

n = 398/6201 [10, 11]

> n = 2/242 [5]

*Maternal risks associated with an increasing number of repeated cesarean sections.*

**Maternal risks of multiple repeat cesarean section**

0.06% n = 10/17,378 [3, 5, 8, 10, 11]

0.09% n = 10/17,378 [3, 5, 8, 10, 11]

> 0.61% n = 52/8542 [3, 8, 12]

1.58% n = 273/17,280 [3, 5, 10, 11]

0.59% n = 104/17,388 [3, 8, 10, 11]

0.43% n = 75/17,378 [3, 8, 10, 11]

0.36% n = 63/17,438 [3, 8, 10, 11]

1.35% n = 231/17,170 [3, 10, 11]

> 7.27% n = 8/110 [5]

**First CS Second CS Third CS ≥4 CS**

0.23% n = 17/7201 [3, 5, 8, 10, 11]

0.18% n = 17/7201 [3, 5, 8, 10, 11]

> 3.71% n = 29/782 [3, 8]

2.23% n = 157/7050 [3, 5, 10, 11]

0.63% n = 45/7106 [3, 8, 10, 11]

0.91% n = 65/7106 [3, 8, 10, 11]

0.67% n = 48/7106 [3, 8, 10, 11]

1.22% n = 85/6955 [3, 10, 11]

20.00% n = 19/95 [5]

0.81% n = 20/2461 [3, 5, 8, 10, 11]

0.85% n = 20/2461 [3, 5, 8, 10, 11]

> 4.34% n = 41/945 [3, 4, 8, 13]

5.35% n = 142/2652 [3, 5, 10, 11, 13, 14]

> 1.95% n = 47/2408 [3, 8, 10, 11]

2.49% n = 66/2652 [3, 8, 10, 11, 13]

> 2.57% n = 62/2408 [3, 8, 10, 11]

2.87% n = 72/2510 [3, 10, 11, 13]

> 15.15% n = 45/297 [5, 13]

*DOI: http://dx.doi.org/10.5772/intechopen.86334*

Bladder injury 0.09%

Bowel injury 0.13%

Uterus rupture 0.43%

Blood transfusion 4.05%

ICU admission 1.99%

Placenta accreta 0.56%

Placenta previa 6.41%

Severe adhesions 0.83%

Cesarean hysterectomy

**Table 1.**

**3.1 Urological and intestinal injury**

**3.2 Uterine scar rupture**

The results of **Table 1** demonstrate a slightly increased rate of injury of other intraabdominal organs with increased number of repeat cesarean section. Most of the relevant studies identified a significant difference in both bladder and bowel injuries between lower and higher order elective repeat cesarean section [3–7]. Particularly after more than three prior cesarean sections, the risk of any injury rises substantially [15]. This common finding is probably due to the higher rate of severe adhesions after higher order multiple repeat cesarean section. A frozen situs with multiple severe adhesions needs longer operation time and good surgery skills resulting in higher risks of any injury [16]. Overall a bladder or bowel injury is a quite rare complication in women with multiple repeat cesarean sections.

Uterine dehiscence or scar rupture is one of the most feared risks in women with multiple repeat cesarean sections. As expected from the usual clinical experience, the dates of **Table 1** show an increased rate of uterine rupture with rising number of repeat cesarean section, again especially in the group of higher order cesarean section (more than three). Surprisingly in reality, most of the analyzed studies confirm


**Table 1.**

*Recent Advances in Cesarean Delivery*

delivery.

**2. Data collection**

cesarean delivery.

reports.

delivery.

Although cesarean section is now safer than it has ever been before, there are some knowledge gaps, and there is uncertainty among many obstetricians about the risks involved in multiple cesarean sections, especially when the number exceeds four. Thus, we would like to summarize the results of the most important studies investigating maternal and fetal risks in multiple repeat cesarean sections enabling and facilitating the counseling of parents and the decision-making for

We did a systematic literature review of PubMed and the Cochrane Database. Search terms used were multiple cesarean section, repeat cesarean delivery, maternal morbidity, neonatal morbidity, maternal and fetal outcome of multiple cesarean section, bladder injury, uterine scar rupture, placenta increta/percreta, hysterectomy, hemorrhage and transfusion, adhesions after repeat cesarean section, vaginal birth after cesarean section, VBAC after cesarean section, and timing of repeat

Prior to beginning the search, we defined inclusion and exclusion criteria. Inclusion criteria were randomized controlled trials, cohort studies, case–control studies, systematic reviews, meta-analysis, and the above search terms. Exclusion criteria were comments, letters to the editor, personal communications, and case

The authors selected the articles first through focused review of the abstracts. Eligible studies underwent full text review. We identified a total of 2190 studies of which 1999 were excluded for not meeting either the inclusion criteria or exclusion

A total of 38 studies and 2 Cochrane systematic reviews ranging from 2005 to 2018 were included in the final analysis. All manuscripts were retrieved in elec-

The references of the most important studies were again checked for eligibility as part of the search strategy. Data from the randomized controlled retrospective trials and Cochrane systematic reviews were extracted by topic, and data were

Thus, the result of this chapter is a review of the safety and risks associated with multiple repeat cesarean section for both the mother and the baby. This can be helpful for the counseling of parents and the decision-making of the mode of

The results of the most important maternal risks of multiple repeat cesarean sections are summarized (**Table 1**). In total eight studies were eligible and were included in this review. Furthermore, each one of the risks is discussed in detail. The results of **Table 1** demonstrate that the frequency of bowel and bladder injury is about 0.1% with up to three previous cesarean sections and just under 1% thereafter [3–7]. Uterine rupture is <1% up to two cesarean sections but increases thereafter to about 4%. Blood transfusions are common and required in up to 5%. Intensive care does not increase substantially and is less than 2% (and may also be due to underlying diseases). Hysterectomy and placenta accreta are less than 1% for up to three cesarean sections but 2.5–3% in more than four. Severe adhesions are

criteria or for not answering the research question.

already common in more than one cesarean section.

tronic PDF format and analyzed in detail.

grouped and reanalyzed.

**3. Maternal risks**

**38**

*Maternal risks associated with an increasing number of repeated cesarean sections.*

### **3.1 Urological and intestinal injury**

The results of **Table 1** demonstrate a slightly increased rate of injury of other intraabdominal organs with increased number of repeat cesarean section. Most of the relevant studies identified a significant difference in both bladder and bowel injuries between lower and higher order elective repeat cesarean section [3–7]. Particularly after more than three prior cesarean sections, the risk of any injury rises substantially [15]. This common finding is probably due to the higher rate of severe adhesions after higher order multiple repeat cesarean section. A frozen situs with multiple severe adhesions needs longer operation time and good surgery skills resulting in higher risks of any injury [16]. Overall a bladder or bowel injury is a quite rare complication in women with multiple repeat cesarean sections.

#### **3.2 Uterine scar rupture**

Uterine dehiscence or scar rupture is one of the most feared risks in women with multiple repeat cesarean sections. As expected from the usual clinical experience, the dates of **Table 1** show an increased rate of uterine rupture with rising number of repeat cesarean section, again especially in the group of higher order cesarean section (more than three). Surprisingly in reality, most of the analyzed studies confirm this trend but also report that multiple prior cesarean deliveries were not significantly associated with an increased risk for uterine rupture [3, 16, 17]. Between the different studies, the definition and counting of incomplete or complete uterine dehiscence, small membranic uterine scar, and real uterine rupture are heterogeneous. Also a uterine rupture can sometimes not be clearly detected. In conclusion, uterine rupture is apparently an existing risk but does not seem to be critical and significant for up to two previous cesarean sections.

#### **3.3 Hemorrhage**

The topic hemorrhage includes different maternal characteristics such as total hemoglobin decrease, blood loss >1500 ml, any blood transfusion, or massive blood transfusion (more than 4 units). Therefore there is inconsistency on the investigated characteristics depending on the definitions used.

The results of the trials show (**Table 1**) that the quantity of any blood transfusion and also the rate of ICU admission are higher in the first cesarean section on the one side and in the higher order repeat cesarean section (≥4) on the other side than the number of transfusion in the second and third cesarean sections [3, 5, 10, 11, 13, 14]. The increased number of blood transfusions and lengthened intensive care hospitalization following the first cesarean section may be explained by the fact that in this cohort, emergency deliveries and more unexpected situations are included, compared with the cohort of the elective second or third cesarean sections.

Some of the analyzed studies pointed out that there is a significant higher rate of blood loss or any blood transfusion especially in the group of more than three repeat cesarean sections [3, 7, 13, 15, 18]. This may be due to a higher rate of adhesions, visceral injury, and possibly abnormal placentation (see also 3.4.). There are a few trials where no differences in blood transfusions between the cohorts could be found [6, 16].

#### **3.4 Abnormal placental invasion and hysterectomy**

Abnormal placental invasion included several characteristics: placenta accreta, increta or percreta, and placenta previa. Placenta accreta is a severe obstetric complication characterized by abnormally deep attachment of the placenta. Placenta increta or percreta describes the more invasive placental attachment to the uterine wall, whereas placenta previa locks the natural birth canal. These placental variations can lead to cesarean hysterectomy and/or a life-threatening maternal hemorrhage.

Like with the other maternal risks, a higher order repeat cesarean section (more than three) means a significant higher rate of placenta praevia, placenta accreta, and hysterectomy (**Table 1**) [3, 8, 10, 11].

Placenta accreta is probably the most clinically significant maternal morbidity subsequent to cesarean delivery because of the association with life-threatening hemorrhage that frequently results in peripartum hysterectomy, cystectomy, and also iatrogenic preterm birth [10, 19–21]. The increase of the incidence of placenta accreta seems to be directly related to the increasing number of multiple cesarean deliveries and is therefore associated with maternal and perinatal morbidities [7, 10, 11].

The incidence of placenta previa also rises together with increased number of cesarean section [3, 8, 10, 11, 22]. Another study pointed out that the rate of placenta previa increased from nearly 1% with one previous cesarean section to about 2.8% with more than three cesarean deliveries [7]. Our results demonstrate (**Table 1**) that even a single prior cesarean delivery can increase the risk for placenta previa [23].

**41**

**Figure 1.**

*(with permission).*

*Maternal and Fetal Risks in Higher Multiple Cesarean Deliveries*

It is also interesting that compared with women with placenta previa and no previous cesarean section, women with placenta previa and more than three cesarean deliveries had a statistically significant increased risk of accreta (3.3–4% vs. 50–67%), hysterectomy (0.7–4% vs. 50–67%), and composite maternal

As explained above, placenta previa and placenta accreta were found to be one of the most important risk factors in terms of the need for hysterectomy [19]. Therefore, the rate of hysterectomy after multiple repeat cesarean section rises

Altogether the results suggest that abnormal placentation is one of the most significant factors by analyzing the adverse maternal outcome after multiple cesarean

Long-term complications are essentially due to the risk of severe adhesions after multiple cesarean sections (**Figure 1**). Adhesions can be the consequence of nearly every operation and can represent a serious problem for the delivery of women with

The results of **Table 1** show that severe adhesions increased parallel to the number of performed repeat cesarean section [10, 24–26]. Especially the rise of the adhesions' rate after more than three cesarean sections is dramatical. Both the incidence and severity of adhesions have been demonstrated to increase with increasing numbers of cesarean deliveries. Adhesions have been also associated with increased operative time, increased blood loss, and increased risk of

Altogether, the rate of severe adhesions after multiple repeat cesarean section is one of the most important keys for maternal outcome after multiple repeat cesarean

In summary of the maternal outcome, the risk of some rare but serious maternal

morbidities such as visceral injury, hemorrhage, abnormal placentation, hysterectomy, or severe adhesions is importantly increased with the number of multiple repeat cesarean section. There is no clear absolute threshold for the number of cesarean sections, but a total of four or more cesarean deliveries was identified as

*The Omentum majus is adherent to the anterior uterine wall in a women with three prior cesarean sections* 

the critical level for most of the major complications.

parallel to the rate of placenta previa and accreta [3, 8, 10, 11, 13].

*DOI: http://dx.doi.org/10.5772/intechopen.86334*

morbidity (15% vs. 83%) [7].

**3.5 Long-term complications**

multiple repeat cesarean sections.

section.

visceral injury.

section.

*Maternal and Fetal Risks in Higher Multiple Cesarean Deliveries DOI: http://dx.doi.org/10.5772/intechopen.86334*

It is also interesting that compared with women with placenta previa and no previous cesarean section, women with placenta previa and more than three cesarean deliveries had a statistically significant increased risk of accreta (3.3–4% vs. 50–67%), hysterectomy (0.7–4% vs. 50–67%), and composite maternal morbidity (15% vs. 83%) [7].

As explained above, placenta previa and placenta accreta were found to be one of the most important risk factors in terms of the need for hysterectomy [19]. Therefore, the rate of hysterectomy after multiple repeat cesarean section rises parallel to the rate of placenta previa and accreta [3, 8, 10, 11, 13].

Altogether the results suggest that abnormal placentation is one of the most significant factors by analyzing the adverse maternal outcome after multiple cesarean section.

#### **3.5 Long-term complications**

*Recent Advances in Cesarean Delivery*

**3.3 Hemorrhage**

significant for up to two previous cesarean sections.

gated characteristics depending on the definitions used.

**3.4 Abnormal placental invasion and hysterectomy**

and hysterectomy (**Table 1**) [3, 8, 10, 11].

this trend but also report that multiple prior cesarean deliveries were not significantly associated with an increased risk for uterine rupture [3, 16, 17]. Between the different studies, the definition and counting of incomplete or complete uterine dehiscence, small membranic uterine scar, and real uterine rupture are heterogeneous. Also a uterine rupture can sometimes not be clearly detected. In conclusion, uterine rupture is apparently an existing risk but does not seem to be critical and

The topic hemorrhage includes different maternal characteristics such as total hemoglobin decrease, blood loss >1500 ml, any blood transfusion, or massive blood transfusion (more than 4 units). Therefore there is inconsistency on the investi-

The results of the trials show (**Table 1**) that the quantity of any blood transfusion and also the rate of ICU admission are higher in the first cesarean section on the one side and in the higher order repeat cesarean section (≥4) on the other side than the number of transfusion in the second and third cesarean sections [3, 5, 10, 11, 13, 14]. The increased number of blood transfusions and lengthened intensive care hospitalization following the first cesarean section may be explained by the fact that in this cohort, emergency deliveries and more unexpected situations are included,

Some of the analyzed studies pointed out that there is a significant higher rate of blood loss or any blood transfusion especially in the group of more than three repeat cesarean sections [3, 7, 13, 15, 18]. This may be due to a higher rate of adhesions, visceral injury, and possibly abnormal placentation (see also 3.4.). There are a few trials where no differences in blood transfusions between the cohorts could be found [6, 16].

Abnormal placental invasion included several characteristics: placenta accreta,

Placenta increta or percreta describes the more invasive placental attachment to the uterine wall, whereas placenta previa locks the natural birth canal. These placental variations can lead to cesarean hysterectomy and/or a life-threatening maternal

Like with the other maternal risks, a higher order repeat cesarean section (more than three) means a significant higher rate of placenta praevia, placenta accreta,

Placenta accreta is probably the most clinically significant maternal morbidity subsequent to cesarean delivery because of the association with life-threatening hemorrhage that frequently results in peripartum hysterectomy, cystectomy, and also iatrogenic preterm birth [10, 19–21]. The increase of the incidence of placenta accreta seems to be directly related to the increasing number of multiple cesarean deliveries and is therefore associated with maternal and perinatal

The incidence of placenta previa also rises together with increased number of cesarean section [3, 8, 10, 11, 22]. Another study pointed out that the rate of placenta previa increased from nearly 1% with one previous cesarean section to about 2.8% with more than three cesarean deliveries [7]. Our results demonstrate (**Table 1**) that even a single prior cesarean delivery can increase the risk for placenta

increta or percreta, and placenta previa. Placenta accreta is a severe obstetric complication characterized by abnormally deep attachment of the placenta.

compared with the cohort of the elective second or third cesarean sections.

**40**

previa [23].

hemorrhage.

morbidities [7, 10, 11].

Long-term complications are essentially due to the risk of severe adhesions after multiple cesarean sections (**Figure 1**). Adhesions can be the consequence of nearly every operation and can represent a serious problem for the delivery of women with multiple repeat cesarean sections.

The results of **Table 1** show that severe adhesions increased parallel to the number of performed repeat cesarean section [10, 24–26]. Especially the rise of the adhesions' rate after more than three cesarean sections is dramatical. Both the incidence and severity of adhesions have been demonstrated to increase with increasing numbers of cesarean deliveries. Adhesions have been also associated with increased operative time, increased blood loss, and increased risk of visceral injury.

Altogether, the rate of severe adhesions after multiple repeat cesarean section is one of the most important keys for maternal outcome after multiple repeat cesarean section.

In summary of the maternal outcome, the risk of some rare but serious maternal morbidities such as visceral injury, hemorrhage, abnormal placentation, hysterectomy, or severe adhesions is importantly increased with the number of multiple repeat cesarean section. There is no clear absolute threshold for the number of cesarean sections, but a total of four or more cesarean deliveries was identified as the critical level for most of the major complications.

#### **Figure 1.**

*The Omentum majus is adherent to the anterior uterine wall in a women with three prior cesarean sections (with permission).*
