Chapter 6: Obesity in the Obstetric Intensive Care Patient

Despite the widely described negative consequences of obesity on health, the obesity epidemic continues to challenge clinicians, researchers, public health policy makers, and the healthcare system, while placing large segments of our population at risk for a multitude of serious maladies and premature death. The problem is not solely limited to the developed world, as obesity has become a World Health Organization (WHO) focus as it relates to global health initiatives. Cancer, orthopedic complications, diabetes, hypertension, stroke, heart disease, premature death and other serious complications (Table 6-1) have been well described, and yet the public health goal of the populace achieving a normal body mass index (BMI) has been elusive. Sadly, obesity is a well-recognized “common denominator” to preventable mortality, and obese (as well as overweight) adults have been shown to be at significantly higher risks for any-cause mortality, than their leaner counterparts. The unfortunate trend toward a sedentary lifestyle and unhealthy eating habits has likely contributed to this unfortunate and costly situation, although unquestionably, myriad psychosocial, economic, and environmental factors are likely contributory. Ironically, despite the decades-long and wide availability of dietetic, fat-free, low-fat, sugar-free, and low-calorie foods and beverages, not to mention the ubiquitous presence of health clubs in our communities, there are more obese Americans today than at any previous time in our history. More than 78 million American adults are obese, which is more than one-third of the adult population, and account for nearly $150 billion of annual obesity-related healthcare expenditures. While obesity is now recognized in 12.5 million American children and adolescents (17% of this population), sadly, nearly one-third of all children ages 2 to 19 years are now either overweight or obese. The prevalence of obesity for adult men and women is now equivalent (35.7% vs 35.8%, respectively), with prevalence increases in recent decades noted primarily in men. Despite some differences in obesity prevalence based on levels of education, income, and ethnicity or race, it is clear that over the past decades, obesity rates have increased for both men and women of all socioeconomic strata. While the number of obese Americans stood at just 13% in 1962, presently, approximately 2 in 3 US women are either overweight or obese, with the highest prevalence noted in the non-Hispanic Black population. Colorado is the “leanest" state, with just over 20% of its population obese, while the “heaviest” state is Mississippi, with nearly 35% of its adult population obese. Clearly, the Healthy People 2010 goals for 15% obesity among adults and 5% in children were not met. In fact, the average BMI of adult women in the United States is 28.7. This unfortunate “state of the weight” in the United States may ultimately undo the steady gains in overall health we have enjoyed as Americans since the dawn of the 20th century, and now contributes to the deaths of 300,000 Americans annually. The remarkably high prevalence of this condition and its significant negative impact on overall health makes its prevention and treatment a top priority for all healthcare disciplines.

Coexisting diabetes is a particularly significant comorbidity and affects nearly 10 million US obese women, with its prevalence having increased 61% since 1991. Nearly 4% of the overall adult female population is both obese and diabetic, and among diabetic women, more than 80% are either overweight or obese. This is significant in that obesity in persons with diabetes is associated with poorer control of blood glucose levels, blood pressure, and cholesterol, placing obese individuals with diabetes at higher risk for both cardiovascular and microvascular disease.

As with many other adverse health measures, disparity in obesity exists. African-American women have the highest prevalence of obesity (53%), as compared to Hispanic women (41.4%), and non-Hispanic white women (32.3%). While fortuitously, very recent trends indicate a slowing, if not plateauing of the prevalence of obesity overall, continued increases are unfortunately noted for non-Hispanic black women and Mexican-American women. This is particularly poignant as African-American women incur the greatest numbers of years of life lost to obesity-related premature mortality. Our patients with limited economic means appear to be disproportionally affected by obesity, given a relatively low prevalence of 29% for those at or 350% above poverty, while those women with income below 130% of the poverty level have an increased prevalence to 42%. Additionally, disparity in obesity rates among children is noted with the startling finding that 1 in 7 low-income preschool-aged children are now obese. Nearly one-third of 3.7 million children aged 2 to 4 years are either obese or overweight. The percentage of overweight children (ages 6-11) has doubled since the early 1980s, while the percentage of overweight adolescents has nearly tripled!

Obesity and Pregnancy

While the clinical reality of the profound impact obesity has on perinatal risk is well recognized by the busy obstetrical provider “in the trenches,” a plethora of research into this subject does in fact support these unfortunate perceptions. Obesity negatively impacts virtually all adverse pregnancy outcomes, among which are increased risks for congenital malformations, diabetes, aberrations in fetal growth, labor abnormalities, a higher cesarean section rate, and greater morbidities associated with cesarean delivery. Newly emerging information would also suggest and support the additional burden of obesity in negatively impacting fetal programming, thus deleteriously impacting the long-term health of the next generation, as increased prepregnancy BMI is a known risk factor for childhood obesity. Obesity complicating pregnancy has also been recognized as a significant contributor to an increased use of perinatal healthcare resources, contributing to the ever-increasing costs of health care.

The complications and challenges posed by obesity in the care of these patients test even the most skilled practitioner, especially as it relates to prenatal diagnosis and intrapartum care. Even the most dreadful of obstetric complications, maternal death, appears to be on the rise in the 21st century, with obesity now recognized as a significant contributor. These patients are indeed high risk and deserving of intense efforts to minimize morbidity and mortality when possible, and thus improve perinatal outcome. This chapter will serve to inform the reader of the various aspects of critical obstetric care for the obese gravida, reviewing antepartum, intrapartum, and postpartum considerations.

Obesity has been defined and described in a variety of descriptive ways, with terms such as severe, extreme, super, massive, morbid, and even “grotesque” appearing in the literature to describe different degrees. Until relatively recently, standardized descriptive definitions for overweight and obesity were lacking, however the BMI (Table 6-2) is now used throughout the literature to indicate the specific patient population being investigated, and thus is the standard measure utilized to determine categories of body weight. The terms overweight and obesity both describe ranges of weight that are greater than what is generally considered healthy for a given height. The terms also identify ranges of weight that have been shown to increase the likelihood of disease and other adverse health consequences. Importantly, BMI correlates with the amount of body fat, but does not directly measure it. Thus, some individuals such as athletes may have a BMI that identifies them as overweight even though they do not have excess body fat. Other methods of estimating body fat and body fat distribution include measurements of skinfold thickness and waist circumference, calculation of waist-to-hip circumference ratios, and techniques such as ultrasound, computed tomography, and magnetic resonance imaging.

Obesity is almost always associated with an excess of caloric intake versus expenditure or physical activity, although as noted above, a myriad of factors (psychosocial, economic, and environmental) may play roles as well. A small percent may be caused by a diverse group of neurologic and endocrine disorders (Table 6-3). An adult with a BMI greater than or equal to 30 is considered to be obese, while an individual with a BMI calculation between 25 and 29.9 is considered overweight. Classes of obesity have also been described, as noted in Table 6-2. While the overall obesity epidemic is well known, significant increases in prevalence for women in the highest BMI categories are also noted. While more than 50% of all pregnant women are overweight or obese, 8% of women of reproductive age are extremely obese (BMI ≥40), and the percentage of women with a BMI of greater than or equal to 50 has increased 5-fold over the past 20 years. This is somber data, as extreme obesity is associated with the most severe general health and perinatal complications.

Given the health implications of obesity, bariatric surgery has become quite common and is among patients of reproductive age not infrequently. In fact, of all these procedures, half are done in women of reproductive age. Pregnant patients with a history of gastric surgery for obesity should be counseled appropriately and surveillance during prenatal care heightened. It is generally recommended to delay childbearing for 12 months postsurgery to provide time to optimize weight loss and reduce potential adverse effects of nutritional deficiencies. While some outcomes have been noted as improved with weight loss following bariatric surgery, such as preeclampsia, gestational diabetes, and fetal macrosomia, reports have shown an increased risk for gastric band complications during pregnancy and nutritional deficiencies. Gastrointestinal hemorrhage and other procedure-related complications, including fetal and maternal death have been reported during pregnancy. Patients with this surgical history with abdominal complaints should be evaluated thoroughly and without delay, and physical findings consistent with an acute abdomen should be met with a low threshold for surgical consultation and exploration. A large percentage of postbariatric surgery patients will still meet the criteria for being obese during pregnancy, and at continued risk of obesity-related adverse perinatal outcomes. Preconception counseling is highly recommended, and achievement of a normal BMI (18.5-24.9) prior to pregnancy should be looked at as a primary goal to reduce risks for adverse outcomes. Tables 6-4 and 6-5 include the major maternal and fetal risks associated with obesity in pregnancy.

Pathophysiology

In pregnancy, blood volume and cardiac output increase approximately 40% with further increases of cardiac output during labor and delivery, reaching values 80% greater than prepregnancy values. Obesity accentuates these changes as blood volume and cardiac output expand in proportion to the increase in body fat and tissue mass. Pharmacodynamics for drug therapy may be altered because obese patients have a larger volume of distribution for lipophilic drugs, but a decrease in lean body mass and tissue water. These changes may predispose obese patients to both subtherapeutic and toxic responses to medications.

During pregnancy, a state of relative hyperventilation exists, which may be mediated through progesterone. Respiratory rate does not change, however with increased tidal volume, an approximate 50% increase in minute ventilation occurs, with a resultant increase in Pao₂ and decrease in Paco₂. Therefore, when evaluating respiratory complaints, beware the “normal" Pco₂. Obese patients demonstrate significant abnormal changes in respiratory physiology. In fact, obese gravidae have markedly diminished functional residual capacity, and except for a relatively preserved residual volume (in obese patients over 40 years of age), all lung volumes, vital capacity and total lung capacity are significantly reduced. In labor, Po₂ is diminished. Furthermore, heightened demand for ventilation, elevated work of breathing, respiratory muscle inefficiency, and diminished respiratory compliance has been shown. Ventilation to perfusion ratio abnormalities and hypoxemia, especially in the supine position further demonstrate the potential adverse impact of obesity on maternal respiratory physiology. Total compliance in obesity diminishes by an average of 50%, which is equivalent to placing a 50-lb weight on the chest and abdomen of a nonobese patient! These respiratory changes in the obese parturient cause the work of breathing to be increased 3 times that of normal. Desaturation occurs more rapidly with apnea, as during apnea, oxygen requirements are provided by the functional residual capacity. With diminished functional residual capacity and increased oxygen requirement, preoxygenation prior to intubation is particularly relevant.

Obesity may also be associated with obstructive sleep apnea (OSA), which refers to apnea (absent or severely reduced airflow) during sleep despite respiratory effort, which can predispose to right-sided heart failure and secondary pulmonary hypertension. Antepartum identification of OSA helps in planning interventions to reduce respiratory morbidity, which can be aggravated by immobility, body position, pain, and use of opioids. A low threshold for evaluation of sleep disorders, pulmonology consultation, sleep medicine consultation, and maternal echocardiography is suggested. Treatment with continuous nasal positive airway pressure (CPAP) may improve outcome. The increase in cardiac work in these patients should also be considered in evaluation of underlying cardiac dysfunction. While data are limited, OSA may further increase the risk for preeclampsia and gestational diabetes. Even in the absence of OSA, consideration for performing maternal echocardiography is reasonable for patients with greater classes of obesity, especially in the presence of coexisting hypertension given the potential for preexisting hypertensive cardiomyopathy (Table 6-6).

The intrapartum management (Table 6-7) of the obese patient in labor is a multidisciplinary team effort. The obstetrician, labor and delivery nurse, obstetric anesthesiologist, and nurse anesthetist should have the unified focus of achieving the best perinatal outcome possible. Maternal fetal medicine specialists often serve as an integral component of this team. Medical consultants who have participated in evaluating and treating the patient for coexisting medical complications should be notified of the patient’s admission to labor and delivery, or such specialists (eg, cardiologist, pulmonologist, endocrinologist) called upon for consultation if previously unrecognized medical complications occur. Given the marked physiologic changes occurring in the obese gravid patient and the high probability of coexisting medical complications, it is suggested that patients at highest risk (higher classes of obesity) receive anesthesia consultation soon after admission to labor and delivery. Given the significant intrapartum risks that may occur in these patients, it would be reasonable to consider “in-house” anesthesia and obstetrical response capabilities as important in the management of those obese patients at highest risk (eg, extreme obesity, preexisting medical complications/comorbidities, prior abdominal surgery). Maternal transport or prenatal referral to physicians who work in a tertiary care environment may be indicated for such patients. Additionally, there may be specific equipment needs to accommodate the obese patient (eg, larger and stronger operating tables, wheelchairs, lifts, long instruments, large blood pressure cuffs, large pneumatic compression devices), and as such, hospitals should be prepared.

A thorough history and physical examination should be undertaken upon the patient’s admission to labor and delivery. In addition to careful evaluation of the patient’s cardiovascular and pulmonary status, meticulous assessment of the patient’s airway is critical, including an evaluation for pharyngeal edema in those patients with preeclampsia. This cannot be overemphasized, as it has been reported that 80% of all anesthesia-related maternal mortality occurred among obese patients, and the inability to accomplish endotracheal intubation was the principal cause. Securing intravenous access and accurate blood pressure monitoring may also prove challenging due to the obese body habitus. The use of central venous access and an arterial line may be helpful in individual cases. Clinicians tending to patients with extreme obesity in labor are encouraged to delineate a clear plan in their minds for procuring additional surgical assistance, should cesarean section be required or other intrapartum complications arise.

Continuous pulse oximetry and electronic fetal monitoring should be employed. If external fetal heart rate and contraction monitoring are limited by the patient’s adiposity or requirements for positioning, internal uterine pressure catheter and fetal scalp electrode placement may be necessary. Particular attention should be given to the obese gravida’s laboring position, with the left lateral position preferred to increase maternal oxygenation, uteroplacental blood flow, and prevent aortocaval compression. Obese patients may also benefit from elevation of the head and chest to prevent airway closure and improve oxygenation as well as overall comfort. Continuous pulse oximetry will provide the clinician with important information with respect to maternal oxygen saturation and allow for ongoing evaluation of hypoxemia and guide the administration of supplemental oxygen as needed, with the goal of maintaining saturation levels at greater than or equal to 95%. Furthermore, maternal pulse oximetry can be an adjunct to assist in the assessment of fetal heart rate monitoring accuracy, given oftentimes noted difficulty with external monitoring in those patients with extreme obesity. Labor abnormalities are not uncommon, and close evaluation of the conduct of labor is warranted. Obese women are at greater risk for delivering a macrosomic infant, and therefore attendants must be prepared for the potential complication of shoulder dystocia, as well as postpartum hemorrhage and fourth-degree vaginal lacerations.

Another important aspect of labor management includes maximizing pulmonary function and decreasing myocardial oxygen requirements. Recall that the obese gravida’s respiratory work requirement is approximately 3 times that for the gravida with a normal BMI. Epidural anesthesia decreases respiratory work, improves oxygenation, and by relieving pain, can decrease the release of catecholamines, which cause increased cardiac work (output), all beneficial attributes. Perhaps the most important aspect of epidural anesthesia lies in the fact that in an emergent situation, should cesarean section be required, a regional anesthetic can be administered through the existing catheter to achieve surgical level anesthesia. It has been shown that neonatal outcome is not compromised by this approach. This is critically important as historically difficult intubation has been noted in approximately 6% of women undergoing cesarean section. Failed intubation occurs approximately 10 times more often than that observed in general surgical patients, and 90% of maternal deaths from anesthetic causes are attributed to general anesthesia, primarily due to complications of aspiration of gastric contents and failed endotracheal intubation. While recent reductions in the general anesthesia-related maternal mortality have been noted, it has also been currently observed that among all delivery deaths attributed to complications of anesthesia, 86% occur among women undergoing a cesarean section, with nearly twice the case-fatality rate noted for anesthesia-related deaths associated with general anesthesia. Thus, the literature would indicate a significantly lower risk of maternal mortality in women undergoing cesarean section under regional anesthesia. Also, as the risks of general anesthesia for the obese parturient are intensified due to greater difficulty in intubation secondary to anatomic barriers and a greater gastric volume with lower pH and diminished barrier pressure (difference between lower esophageal sphincter tone minus intragastric pressure), regional anesthesia should be considered the anesthetic of choice unless contraindications exist. Such contraindications may include coagulopathy, thrombocytopenia, maternal therapeutic anticoagulation, recent use of low-molecular-weight heparin, hemodynamic instability, acute hemorrhage, and infection over the site of planned needle insertion. With increased utilization of regional anesthesia, ongoing reductions of anesthetic-related maternal mortality are anticipated. It has also been shown that there is a greater likelihood for obese patients to require multiple attempts before successful regional anesthesia placement is achieved, which is particularly problematic in the emergent situation. Therefore, the “prophylactic” placement of an epidural catheter, nonemergently in the obese laboring patient (even prior to a desire for labor analgesia) should be strongly considered in the intrapartum management of these patients. Other pertinent benefits of regional anesthesia in the obese parturient include reduction in postoperative pulmonary complications. Long-acting spinal or epidural narcotics are commonly administered for postoperative analgesia, and their use reduces risks of respiratory depression from parenteral narcotics. Additionally, patients treated in this manner will generally ambulate earlier, which is likely to decrease risk of thromboembolic complications. Increased layers of fat deposition in the patients’ back, gross distortion of anatomic landmarks, and difficult patient positioning challenge the anesthesiologists’ skills even under nonemergent circumstances, or can potentially preclude placement altogether.

The obstetric patient is at higher risk of aspiration of gastric contents due to hormonal and physical changes in pregnancy and the use of analgesics. Fasting and the use of pharmacologic prophylaxis can reduce the risk. Intake of solid foods should be avoided by the obese gravida during labor, and further restriction of oral intake should be considered for those at highest aspiration risk (eg, extreme obesity, difficult airway, diabetes). As acidic aspirate from the patient’s stomach can cause severe pulmonary injury, the patient should receive prophylactic administration of a nonparticulate antacid (30 mL of 0.3 M sodium citrate; Bicitra) just prior to anesthesia induction (general or regional) and have the dose repeated each hour if surgery continues beyond 1 hour for the patient with regional anesthesia. In patients at high risk for aspiration, the use of an H₂-receptor blocker (eg, ranitidine; 150 mg po or 50 mg. IV) and proton-pump inhibitors (PPIs [eg, omeprazole; 40 mg IV]) administered during labor may be helpful in reducing the sequelae of aspiration should this potentially lethal complication occur. A dopamine antagonist (eg, metoclopramide; 10 mg slowly IV) reduces peripartum nausea and vomiting, and therefore may help prevent aspiration. At least 60 minutes are required for H₂ antagonists to decrease gastric acidity to a “safe pH” if given parenterally. Therefore, their use is preferred on admission and during labor rather than in the acute situation. For scheduled cesarean section or labor induction of obese gravidae, ranitidine may be administered the night prior to surgery and then repeated on admission to the hospital and at appropriate intervals thereafter. Bicitra should also be administered in addition to an H₂-receptor blocker if cesarean section is required. These prophylactic measures will raise the gastric pH to greater than 3 in nearly 99% of patients. The importance of these measures cannot be overemphasized as pneumonitis and respiratory failure resulting from aspiration of gastric contents has been the most common single cause of maternal mortality related to anesthetic causes. In situations where evaluation of the patient’s airway indicates the probability of difficult intubation, awake intubation and fiberoptic videolaryngoscopy are important considerations. Specialized equipment for difficult intubation should be on hand, checked regularly, and airway drills and algorithm reviews will help prepare the entire anesthesia team for the unanticipated obstetric airway emergency. Again, given these concerns, the obese gravida at high risk for anesthetic complications should preferably have an anesthesia consultation during the course of her prenatal care, and be seen by anesthesia upon admission to labor and delivery is recommended.

The obese parturient is at increased risk for both elective and emergency cesarean delivery. The problem is compounded by the finding that the obese gravida is at further risk that exists for perioperative morbidities associated with cesarean section. The risks for cesarean section and related perioperative morbidities among the obese appear to be “BMI dependent,” in that women with higher BMIs will more likely be delivered by cesarean section, most often due to labor dystocia and nonreassuring fetal heart rate tracings. These obesity-related risks for adverse outcome appear to be independent of other perinatal variables. Risks noted for the obese gravida undergoing cesarean section include emergent indications, unsuccessful initial placement of the epidural catheter, markedly prolonged skin incision to delivery interval, greater blood loss, thromboembolism, prolonged hospitalization, and a nearly 10-fold increase in postoperative endomyometritis and wound infection. Furthermore, the success rate for a trial of labor after cesarean section (TOLAC) appears to be inversely related to BMI, with a failure rate as high as 40% for women with BMI greater than or equal to 40. A success rate of just 13% was reported for a group of women who weighed more than 300 lb. Increased risk for uterine rupture has also been noted in the obese population. Given the potential need for urgent cesarean section in the course of TOLAC and the potential for significant surgical and anesthetic morbidity for the obese gravida, counseling for vaginal birth after cesarean (VBAC) in this population should be tailored to include these important unique issues.

Antibiotic Prophylaxis

Various adjuncts to perioperative care have been utilized to prevent morbidities associated with cesarean section in the obese population. Infectious complications of cesarean section are particularly common among the obese population undergoing cesarean section. Prophylactic antibiotics have been found to be the most significant factor in the reduction of postoperative wound infection and endometritis. In patients undergoing bariatric surgery, a single preoperative 2-g dose of cefazolin resulted in intraoperative serum and tissue levels comparable with those seen in nonobese patients given a 1-g dose. Given this information, and that obese patients demonstrate increases in both volume of distribution and drug clearance for cephalosporins, a single higher dose of prophylactic antibiotics seems reasonable based on currently available pharmacokinetic data.

Thromboembolism Prophylaxis

Fatal pulmonary embolism occurs 10 times more frequently after cesarean section than vaginal delivery. Early ambulation (ie, within 12 to 24 hours after surgery or sooner) can decrease the risk of thromboembolic complications and should be actively encouraged. Compression stockings and pneumatic compression devices placed on the patient before the initiation of surgery and continued postoperatively, either until the patient is fully ambulatory or until hospital discharge is recommended. Pneumatic compression devices applied to the lower extremities before cesarean delivery is now recommended for all women undergoing cesarean section not already receiving thromboprophylaxis. Although adequately powered prospective, randomized, controlled studies have shown thromboprophylaxis to be highly effective in reducing the incidence of venous thromboembolism after moderate-to-high-risk general, urologic, and gynecologic surgery, only 3 small trials enrolling women postcesarean section have been performed. Nevertheless, prophylactic dosing of unfractionated or fractionated low-molecular-weight heparin to decrease thromboembolic complications, especially for those gravidas who are in the highest BMI categories, are immobile and with additional risk factors (eg, diabetes, advanced maternal age) may be beneficial and utilized on an individualized basis. The Publications committee of the Society or Maternal Fetal Medicine (SMFM) suggested pharmacologic prophylaxis consisting of either low-molecular-weight or unfractionated heparin (eg, enoxaparin 40 mg daily or unfractionated heparin 5000 units q12h, respectively) for women requiring cesarean delivery with one and probably 2 or more additional risk factors, especially if they are severe (eg, BMI >50). Risk factors noted were advanced maternal age, prepregnancy BMI greater than 30, multifetal pregnancy, smoking, bed rest or immobility and past history of venous thromboembolism. The duration of therapy is not stated, however it is this author’s practice to continue prophylaxis until the patient is fully ambulatory; a longer duration of therapy to varying degrees is prescribed if the patient has additional risk factors (eg, thrombophilia, prior history of venous thrombosis, BMI >50, prolonged immobility). Although hemorrhagic complications associated with epidural or spinal anesthesia are rare, concern regarding the administration of regional anesthesia in women receiving anticoagulation prompted the American Society of Regional Anesthesia and Pain Medicine (ASRA) to recommend that prophylaxis be held until at least 12 hours after cesarean section or epidural catheter removal, whichever is later.

Table 6-7 reviews the intrapartum and postpartum management recommendations.

Cesarean Section

The importance of the obstetricians’ preoperative hands-on evaluation of the patients’ abdomen while she is positioned on the operating room table cannot be overstated. Particular attention to anatomic landmarks is key, focusing on the pubic symphysis, umbilicus, depth of the pannus, and the degree to which the pannus falls below the pubic symphysis. It is important not to rely upon the umbilicus as a primary landmark for estimating the location of the uterus, as the pubic symphysis and iliac crests will be more reliable and help avoid a dreaded complication where the skin incision is carried down through the pannus, transecting it.

Prior to incision, appropriate patient position (a 15-degree left tilt of the operating table has been suggested) can prevent aortocaval compression, improve fetal oxygenation, provide patient comfort, and lessen maternal respiratory difficulty. Attention to proper positioning will also contribute to reducing the risk of perioperative nerve, joint, and soft tissue injuries. Some clinicians will individualize care based on risk factors (eg, prior abdominal surgery, anemia, placenta previa), and cross match these patients for packed red blood cells, given the increased risk for blood loss. Also, it is imperative to have the proper instruments for the patients’ size. Longer scissors, scalpel handle, cautery tip extender, forceps and clamps, and wider retractors with longer handles are available and can be indispensible.

The incision of choice for cesarean section in obese patients is not entirely clear, given a lack of randomized clinical trials, which is unfortunate given that the incision may affect surgical exposure, ease of delivery, postoperative pain, maternal respiratory effort, wound complications, and postoperative pain. Nevertheless, it has been shown that vertical skin incisions are associated with an approximate 12-fold greater risk of wound complications (defined as the necessity to reopen the wound) compared to a transverse incision. While a vertical incision may offer the most rapid entry into the obese patients’ abdominal cavity, benefits of the transverse incision include a more secure closure, less fat transection, and less postoperative pain. Perhaps the most compelling reason to utilize a transverse incision in the obese gravida is its association with a diminished risk for atelectasis, hypoxemia, and postoperative pain, leading to earlier ambulation and deep breathing, all critically important given the increased risk for pulmonary and thromboembolic complications. Criticisms of the low transverse skin incision include the placement of a surgical wound in the warm, moist intertriginous area beneath the panniculus, potentially increasing the risk of infection, more difficult surgical exposure, and the inability to explore the upper abdomen. For most obese patients, a suggested approach would include the cephalad retraction of the pannus utilizing Elastoplast tape or Montgomery straps attached to the “ether screen” hardware of the surgical bed. This often permits exposure of the lower abdomen, allowing the low transverse skin incision (eg, Pfannensteil) to be made through a minimum of adipose tissue (Fig. 6-1). At times however, the pannus may be too large for cephalad displacement, and doing so may lead to marked cardiorespiratory compromise in the patient with a massive panniculus or retraction that results in the pannus forming a vertical “wall,” precluding access to the lower abdomen. In this situation, or alternatively, a transverse or vertical periumbilical incision may be utilized. This may have greatest applicability in the most extreme obese patients (>500 lb). This allows for excellent exposure without pannus retraction and the potential for cardiorespiratory compromise (Fig. 6-2). The incision circumvents the intertriginous area beneath the pannus and avoids the thick and edematous portion of the panniculus transected in “high Pfannenstiel” or low vertical incisions. The supraumbilical vertical skin incision with a fundal uterine incision with breech extraction of the vertex fetus has been shown to have similar postoperative morbidity in morbidly obese patients when compared to a low transverse abdominal incision.

Be meticulous and cautious with subcutaneous tissue dissection, as large caliber veins may be commonly encountered. Also, be careful not to cut the fascia too far laterally, where diminished visualization compromises the ability to achieve hemostasis should a subfascial vessel be transected. Whichever incision type is chosen, it should be large enough for atraumatic delivery of the fetus. Some have advocated the superiority of surgical technique using less sharp dissection and greater use of manual manipulation of the tissues as in the Joel-Cohen incision and Misgav Ladach method for cesarean section. These techniques have yet to be studied specifically in the obese population, but in principle they are worthy of consideration for this high-risk group.

At times it may be useful to use vacuum extraction assistance at the time of cesarean section. The forces generated with fundal pressure as the vertex is typically delivered at cesarean section will dissipate throughout the large abdomen of the patient and is often not helpful in assisting with delivery.

Uterine closure can be undertaken in the usual manner with close attention to hemostasis. Operative times are longer and blood loss is greater in this population. Often, visualization of the operative field can be compromised and obviously, care must be taken with sharp instruments in a “visually challenged” surgical field. As needle-stick injuries occur commonly and given the risks for infectious disease transmission through these accidents, consideration for blunt needle use should be given. These needles work well with cesarean section, and a survey study has demonstrated their acceptance and efficacy. The use of a specific retractor for the obese patient (Alexis-O; Applied Medical, Rancho Santa Margarita, CA) may assist in providing exposure of the uterus by compressing the subcutaneous tissue depth and mechanically creating a wider field of view. Fascial closure should be undertaken with meticulousness. If a vertical incision is utilized, a Smead-Jones or modified Smead-Jones closure is preferred (Fig. 6-3). Skillful transverse fascial closure, which provides the majority of wound strength during the healing process, is critical. A simple running suture is appropriate utilizing delayed absorbable or permanent suture. A loop 0- or 1-PDS would be a good choice of delayed absorbable suture for this purpose. Wide “bites” incorporating more than 1 cm of fascial tissue from the cut edge should be utilized, stitch intervals should be no greater than 1 cm apart, and excessive tension should be avoided to prevent fascial necrosis, the primary cause of dehiscence.

When the subcutaneous tissue is at least 2 cm in depth, closing the subcutaneous adipose layer will decrease the risk of subsequent wound disruption by 33%. The placement of closed surgical drains within the subcutaneous tissue is generally not recommended, as randomized trials have shown no improvement in wound complication rates.

Subcuticular suture or sterile skin staples may be used for skin closure; however, should staples be used for this purpose, one should be careful not to remove them prematurely in the obese patient, as in general, removal on postoperative day 3 is associated with an increased incidence of skin separation. A randomized trial of these 2 methods in an obese population is lacking, however in general, a decreased risk for wound dehiscence is appreciated with subcuticular closure. Good clinical judgment and close wound inspection prior to hospital discharge will determine which patients may need to return as outpatients for staple removal several days postdischarge.

Finally, these patients should be given thorough discharge instructions including the signs and symptoms of wound infection and dehiscence, endomyometritis, thromboembolic complications (deep venous thrombosis [DVT] and pulmonary embolism), and diligent follow-up with respect to the continued management of any existing medical complications.

In conclusion, the management and care of the obese gravida is extremely challenging and laden with significant risks. One cannot overstate the importance of preparedness. Having sufficient surgical assistance, appropriately sized instruments and a thorough preoperative assessment of the patient’s medical status and body habitus, and its relation to the surgical approach are critical to achieve the best outcome possible given these challenging clinical circumstances. Our recommendations, interventions, and attention to detail may allow us to maximize perinatal outcome and reduce maternal morbidity and mortality for this high-risk group of pregnant women. Hopefully, our efforts in this regard will also allow for the development of a physician-patient relationship built upon mutual trust and rapport, contributing to a positive “long-term” influence of our care on the patient’s obese condition.

As prevention should always be the hallmark of the best medical approach to disease management, it should be emphasized here in closing, that appropriate follow-up for weight loss counseling strategies, be they behavioral, medical, or surgical is critical. Weight loss through these approaches can reduce risk in future pregnancy, and these patients should be counseled to achieve a normal BMI and optimize preexisting medical complications prior to subsequent pregnancy. Preconception counseling should be strongly recommended. Truly, any impact made in this regard has the potential for tremendous health benefit over the patient’s entire life and in subsequent pregnancy.

“Cesarean Section “Pearls” for the Obese Gravida”

1. O: OXYGEN—Decrease maternal myocardial oxygen requirement with adequate analgesia, preferably the “prophylactic epidural." Increase fetal oxygenation by laboring or positioning the patient at a “left-tilt." Monitor maternal oxygen saturation and supplement oxygen as needed.

2. B: BLOOD—Blood loss is greater and postpartum hemorrhage risk is increased. Be sure to supplement patients during prenatal care with iron if anemic. Have the patient typed and crossed as necessary, as the potential need for blood transfusion is foreseeable.

3. E: EQUIPMENT—Be certain to have appropriate equipment that can withstand the weight of the obese gravida: surgical table, commode, wheelchair. Be sure that surgical instruments are appropriately sized. The Alexis Retractor can help provide excellent exposure.

4. S: STAFF—Having sufficient and appropriately trained staff is critical. Surgical assistance is required, not optional. Anesthesiology staff trained in fiberoptic intubation may be critical to a good outcome. Compassion, in addition to skill is mandatory from all staff members.

5. I: INTUBATION RISK—Failed intubation is a cause of maternal death, especially in the obese gravida. A “prophylactic epidural” can minimize this risk and should be strongly considered. Preoperative measures to reduce gastric acidity should be taken.

6. T: THROMBOPROPHYLAXIS—Pregnancy is a risk factor for life-threatening deep venous thrombosis. Additive risks are cesarean section and obesity. Take measures to prevent this complication. Sequential compression devices should be uniformly placed preoperatively, and individual consideration should be given to the use of heparin.

7. Y: YES WE CAN!—While the challenges of caring for the obese gravida can be numerous, especially the seemingly insurmountable operative difficulties of cesarean section in the extremely obese, a positive attitude, combined with good physician-patient communication, meticulous preparation, and ongoing provider education will contribute to positive outcomes in these high-risk scenarios.

Epidemiology

Obesity and Perinatal Outcome

Bariatric Surgery and Pregnancy

Obesity and Surgical Risks, Cesarean Section

Obesity and Anesthetic Morbidity and Mortality

Obesity and Maternal Mortality