Obesity: Unique Challenges at the Time of Cesarean Delivery

*Kristina Roloff, Suzanne Cao, Camille Okekpe, Inessa Dombrovsky and Guillermo Valenzuela*

#### **Abstract**

The obesity epidemic has touched all aspects of obstetric care, including the practice of cesarean delivery. Obesity is an independent risk factor for cesarean delivery, and the increased prevalence of obesity has contributed to the overall rise in primary cesarean delivery seen over the past few decades. Because of the frequent existence of co-morbidities such as hypertension and diabetes, obesity is a plausible contributor to rising maternal mortality. In addition, obese women who undergo both primary and repeat cesarean delivery have a higher chance to develop surgical and post-operative complications, including wound infection and thromboembolic events. Surgical complications increase steadily with increasing maternal weight. In this chapter, we will review the incidence and contributing factors that lead to cesarean delivery in obese patients, peri-operative complications, and strategies to reduce these risks in obese women undergoing cesarean delivery.

**Keywords:** cesarean delivery, obesity, super-obesity

#### **1. Introduction**

Cecelia presents for a routine new obstetric appointment for her second pregnancy. She has had one prior pregnancy, and does not identify any health problems on her intake paperwork. However, she is markedly obese, and her weight is in excess of 500 pounds, more than the average in-office scale can measure. Adequate understanding of risks and management strategies to mitigate her risk is needed to optimize the chances of a health pregnancy outcome.

The prevalence of obesity, defined as body mass index (BMI) ≥ 30 kg/m2 , and super-obesity (BMI ≥ 50 kg/m<sup>2</sup> ) is on the rise in reproductive aged women. Pregnancy complications such as gestational diabetes, preeclampsia, macrosomia, and stillbirth are more common in obese women than in normal weight patients. Many of these complications occur in a dose dependent fashion; the higher the BMI category, the more likely complications are to occur. The obese patient has both an increased risk for needing an indicated primary cesarean delivery, an increased risk for peri-operative complications, and is at higher risk for failed trial of labor after cesarean delivery. The super-obese patient, in particular, presents a unique challenge to obstetricians planning and preparing for cesarean delivery.

In this chapter, we will review the evidence of surgical risk at the time of cesarean delivery, management options to reduce surgical risks, and practical considerations in performing a cesarean delivery in the obese parturient.

## **2. Incidence of cesarean delivery in obese women**

Estimates of primary cesarean delivery rates in obese patients undergoing trial of labor range from 23 to 49%, and increase with increasing maternal BMI (23–46% BMI ≥30 kg/m2 , 30–47% BMI ≥ 40 kg/m<sup>2</sup> , 45–49% BMI ≥ 50 kg/m2 ) [1–5]. The most common indications for cesarean delivery are labor arrest (61%) and nonreassuring fetal status (28%) [1]. Pre-labor primary cesarean delivery also increases with increasing BMI class [5].

### **3. Factors contributing to cesarean delivery in obese women**

The reason for the increased incidence of cesarean delivery in obese women is likely multifactorial, and includes higher chances of macrosomia – and hence labor dystocia, disordered and dysfunctional labor patterns, and provider level responses or bias towards cesarean delivery [5].

The combination of obesity and macrosomia significantly increases the chance of cesarean delivery [6]. Both pre-pregnancy BMI category and gestational weight gain are independent contributors to the development of a large for gestational age or macrosomic infant [7–8]. Obese women tend to have higher gestational weight gain, despite stricter weight gain recommendations, and hence larger birth weight babies [7]. A large fetus, for obvious reasons, predisposes the mother to a protracted labor course and cephalopelvic disproportion leading to an indicated cesarean delivery. In addition, fear of shoulder dystocia and neonatal brachial plexus injury, which occurs more often at delivery of obese women even with lower fetal birth weight, may influence the decision to proceed with cesarean delivery [9]. Because of the chances of fetal macrosomia with advancing gestational age, a strategy of elective induction at term may help to reduce the chances of macrosomia, and hence cesarean delivery. Elective induction was not associated with an increased risk of cesarean delivery in women with BMI ≥ 40 kg/m2 [10].

Obese women also have dysfunctional labor patterns [11]. Obese women are less likely to have spontaneous onset of labor, less likely to achieve vaginal birth following spontaneous labor, and have a higher chance of being exposed to oxytocin than non-obese women [12]. Obese women may require larger doses of oxytocin than their normal weight counterparts, especially when undergoing induction of labor [13]. The pathophysiology of the increased oxytocin requirements and protracted labor course is poorly understood, but may be due to decreased myometrial receptor expression, prostaglandin insensitivity, and impaired myocyte contractility [14]. The dysfunctional and apparently disrupted myometrial activity may contribute to why we see more unplanned cesarean delivery in obese women.

Provider factors also may contribute to the increase chance of cesarean delivery in obese women [15]. Because the decision-to-incision and decision-to-delivery time interval for emergency cesarean delivery is significantly higher in obese women, a recommendation of cesarean delivery may be made earlier, in order to allow adequate time for surgical preparation [16, 17]. The timing of intervention for non-reassuring fetal heart rate patterns likely contributes to increased unplanned cesarean delivery, as well as pre-labor cesarean deliveries [5, 18]. Obese women with prior cesarean delivery are more likely to decline trial of labor after cesarean, which may be due to individual counseling by obstetric providers [19].

Despite the fact that cesarean delivery is performed more often in obese women, it is still a riskier mode of delivery. Planned cesarean delivery, even in super-obese women (BMI ≥ 50 kg/m2 ) does not reduce maternal or neonatal morbidity [1].

**69**

*Obesity: Unique Challenges at the Time of Cesarean Delivery*

Important peri-operative complications of cesarean delivery in obese women include wound complications (infection, wound separation), thromboembolic events, and adverse neonatal complications. A history of three or more prior cesarean deliveries further increases the chance of complications such as transfusion, low 1 min Apgar score, and wound complications [20]. The timing of repeat cesarean – unscheduled or planned – may also increase surgical and neonatal risks, especially since obese women are more likely to develop pregnancy complications prompting unscheduled repeat cesarean delivery [21]. Other surgical risks, such as bowel, bladder, or ureteral injury, or broad ligament hematoma, appear to be comparably infrequent in obese and super obese women like in normal and overweight women [22]. Super obesity also increases the chance of maternal ICU admission and length of hospitalization, which is largely driven by maternal co-morbid

Wound complications – separation and infection, occur in approximately 10% of obese women delivered by cesarean [20, 25–27]. The odds ratio for wound complication in obese women is 1.14–1.65 times normal weight controls, when adjusted for many confounders [25]. There is a marked dose response for wound complications by increasing BMI category, with an odds ratio increase of up to 2.0 for every five-unit increment increase in BMI [28]. Chances of wound infection in super-obese women have been reported as high as 30% [29]. In probably the largest sample reported (38,229 women), wound complications occurred in 14% of women

particular are seen more frequently in patients with super obesity [30].

An increase in operative time in women who are obese is also dose dependent on BMI category [17, 27, 31]. Longer operative time is strongly correlated to post-operative infection, and may be a potential modifiable factor to reduce wound complication [32]. Other peri-operative and surgical strategies that may help prevent wound complications, such as pre-operative antibiotics, choice of skin incision, and wound closure

Other than cesarean delivery, obesity is the most common risk factor for a venous thromboembolic event (VTE) in pregnancy [33]. The classic Virchow's triad of hypercoagulability, endothelial injury, and stasis of blood flow leads to the well-established risk of VTE during pregnancy. Obesity itself, regardless of mode of delivery, is a significant risk factor for VTE, with reported risks of 1.7 to 5.3 (odds ratio) above normal weight controls [34–37]. Obese pregnant women have greater risk for pulmonary embolism than deep-vein thrombosis (DVT); the adjusted odds ratio for DVT is 4.4 (95% CI 1.6–11.9) and for pulmonary embolism is 14.9 (95% CI 3.0–74.8) [35]. Like other complications, VTE has a dose–response relationship with

The exact contribution of the combination of obesity and cesarean delivery to VTEs is difficult to quantify. Immobilization and high BMI have a multiplicative effect on risk for VTE [39]. It is very likely that obesity and cesarean delivery also have multiplicative effects on the chance for VTE. Prevention of VTE during

following cesarean delivery [25]. Wound separations in

*DOI: http://dx.doi.org/10.5772/intechopen.86085*

**4. Surgical complications**

conditions [23, 24].

with BMI ≥ 45 kg/m2

type are reviewed in Section 4.4.

**4.2 Thromboembolic events**

increasing BMI category [38].

cesarean delivery is discussed in Section 6.5.

**4.1 Wound complications**
