Objective
The objective of the study was to determine predictors of cesarean delivery morbidity associated with massive obesity.
Study Design
This was an institutional review board–approved retrospective study of massively obese women (body mass index, ≥50 kg/m 2 ) undergoing cesarean delivery. Bivariable and multivariable analyses were used to assess the strength of association between wound complication and various predictors.
Results
Fifty-eight of 194 patients (30%) had a wound complication. Most (90%) were wound disruptions, and 86% were diagnosed after hospital discharge (median postoperative day, 8.5; interquartile range, 6–12). Subcutaneous drains and smoking, but not labor or ruptured membranes, were independently associated with wound complication after controlling for various confounders. Vertical abdominal incisions were associated with increased operative time, blood loss, and vertical hysterotomy.
Conclusion
Women with a body mass index ≥50 kg/m 2 have a much greater risk for cesarean wound complications than previously reported. Avoidance of subcutaneous drains and increased use of transverse abdominal wall incisions should be considered in massively obese parturients to reduce operative morbidity.
The rate of cesarean morbidity in massively obese women is unknown despite the increasing relevance of these patients in modern obstetrics. The percentage of women with a body mass index (BMI) of 50 kg/m 2 or more has increased 5-fold in the past 20 years. We previously reported that the prevalence of pregnant women with a BMI of 50 kg/m 2 or more delivering at our institution is 1 in 35, and the rate of cesarean delivery in this population is approximately 60%.
For Editors’ Commentary, see Table of Contents
Obesity is a well-recognized risk factor for the development of a wound complication or infection after cesarean delivery. Antibiotic prophylaxis for laboring and nonlaboring women and suture closure of the subcutaneous space are techniques that have been shown to reduce the incidence of wound disruption in metaanalyses of randomized controlled trials. Vertical abdominal incisions and closed suction subcutaneous drains are commonly used to reduce postoperative wound complications for obese patients undergoing cesarean delivery. Evidence suggests, however, that these 2 practices have a negligible or even negative impact on the incidence of wound complications.
Accurate estimation of wound complications heretofore has been limited by previous publications that rely on hospital discharge data, telephone survey, or mailed questionnaire. Therefore, the objective of this study was to determine the rate of operative complications in massively obese parturients (BMI ≥50 kg/m 2 ) undergoing cesarean delivery. Furthermore, we sought to determine whether certain operative practices are associated with increased cesarean morbidity in these patients.
Materials and Methods
Patients
The institutional review board at the Medical University of South Carolina approved this retrospective study. Data were derived from a single regional tertiary referral center between Jan. 1, 2005, and Dec. 31, 2009. All patients undergoing cesarean delivery between 20 and 44 weeks of gestation with a BMI of 50 kg/m 2 or more were included. There were no exclusion criteria. All cases were performed by resident and attending surgeons. Heights and weights were measured at an earlier outpatient prenatal visit. The weight taken within 2 weeks before delivery was used for inclusion in the study. The patient’s recall of her last weight within the 2 previous weeks was used in cases of inpatient transfer.
Methods
Data were abstracted from the outpatient electronic medical record and electronically scanned inpatient charts. Two authors performed independent review of each electronic record, and a single author (M.C.A.) verified the findings of the data abstraction.
Body mass index (kilograms per square meter) was calculated from maternal height and predelivery weight. Gestational age was determined by the last menstrual period or ultrasound dating, according to American College of Obstetrics and Gynecology (ACOG) recommendations. Pregestational type 1 and type 2 diabetes was determined by the patient’s medical histories, and gestational diabetes was determined by abnormal diagnostic testing during pregnancy according to guidelines published by the American Diabetes Association. Pregestational and gestational diabetes were analyzed as a single, combined variable for all analyses. Preeclampsia and chronic hypertension were determined according to guidelines published by ACOG.
Induction of labor was defined as the use of cervical ripening agents or uterine contractile agents in women without regular uterine contractions or women with regular uterine contractions but cervical dilation less than 3 cm. Labor was defined as regular, painful uterine contractions and cervical dilation of 3 cm or greater. Ruptured membranes and chorioamnionitis were diagnosed clinically.
Abdominal incisions were considered vertical or transverse. Transverse incisions were Pfannenstiel incisions in all cases except 1, which was a subumbilical transverse incision. Vertical incisions were all paramedian or midline incisions above or below the umbilicus. Subcutaneous closure was performed with absorbable suture in all cases, and all subcutaneous drains exited through a separate incision. Typical antibiotic prophylaxis during the study period was 1 g of cefazolin except in a small number of cases, which were due to antibiotic allergy or physician preference. During the study period, the results of a randomized controlled trial influenced a practice change in favor of preincision over postcord clamp antibiotic prophylaxis.
Wound complication was defined as either a wound disruption or wound cellulitis. A wound disruption was defined as the partial or complete opening of the deep subcutaneous space. Superficial skin separation was not considered a wound disruption, and these cases were not counted as a wound complication. Underlying causes for wound disruptions included seroma, hematoma, abscess, and fascial dehiscence. For the purposes of this study, wound cellulitis was defined as a physician diagnosis of erythema and warmth spreading beyond the immediate area surrounding the incision and requiring treatment with antibiotics. Simple, mild erythema or induration around the wound was not considered wound cellulitis, and such cases were not counted as a wound complication. Furthermore, uncomplicated yeast infections were not considered a wound complication.
Statistical analysis
Continuous variables were reported as medians and interquartile ranges, and categorical variables were reported as column percents and frequencies. Bivariable analyses with the Wilcoxon rank sum test and χ 2 test (or Fisher’s exact test when appropriate) were performed to assess the relationship between wound complication and various perioperative factors.
Stratified analysis was performed to assess the independent effect of abdominal incision (vertical or transverse) on wound complication. Multivariable logistic regression analysis was used to control for confounding. Unadjusted and adjusted odds ratios with 95% confidence intervals (CIs) were reported, and P < .05 was considered statistically significant. Tests for two-way interaction between dichotomous covariates were performed using the Breslow-Day test, and the Hosmer-Lemeshow goodness-of-fit test was used to assess the fit of multivariable models. The Cochran-Armitage trend test and 1-way analysis of variance (Brown-Mood test) were used to analyze changes in practice patterns over time. Statistical analyses were performed with SAS version 9.1.3 (SAS Institute, Inc, Cary, NC).
Results
A total of 195 women with a BMI of 50 kg/m 2 or greater underwent cesarean delivery during the study period. One woman was excluded from the analysis because of maternal death on postoperative day 0, a result of hemorrhagic complications of placenta accreta. The final study group included 194 women.
A wound complication occurred in 58 cases (30%), 52 of which (90%) were wound disruptions. Fourteen patients (24%) required readmission to the hospital for treatment, and 8 (14%) required reoperation because of a wound complication. One patient with a BMI of 109 kg/m 2 experienced evisceration and required resection of necrotic fascia 10 days after cesarean delivery. All other cases of reoperation required only simple wound debridement. Only 8 of 58 (14%) wound complications were diagnosed before hospital discharge. The remaining wound complications were diagnosed either in the outpatient clinical setting (52%) or the emergency department (34%). The median postoperative day of diagnosis for all wound complications was 8.5 (interquartile range [IQR], 6–11.5 days). Overall, posthospital discharge follow-up records were available for 171 patients (88%), and patients without follow-up did not differ in terms of background or operative characteristics (data not shown).
Women who experienced a wound complication were slightly older and had higher rates of smoking, diabetes, vertical abdominal incision, subcutaneous drain, and blood loss greater than 1000 mL at their cesarean delivery ( Table 1 ). Neither labor nor ruptured membranes were associated with wound complication ( Table 1 ). The great majority of subcutaneous drains were placed in those receiving a vertical abdominal incision ( Table 2 ). Therefore, a stratified analysis was performed to better assess the relationship between vertical abdominal incision and wound complication.
| Variable | No wound complication (n = 136) | Wound complication (n = 58) | OR (95% CI) | P value a |
|---|---|---|---|---|
| Maternal age, y b | 28.0 (25–33) | 31.0 (26–36) | — | .04 |
| BMI, kg/m 2 b | 54.8 (51.5–58.4) | 54.7 (51.3–58.7) | — | .77 |
| Race/ethnicity, % | ||||
| White | 22.1 (30) | 29.3 (17) | — | .52 |
| Black | 72.8 (99) | 67.2 (39) | ||
| Hispanic | 5.2 (7) | 3.5 (2) | ||
| Payer status, % | ||||
| Private insurance | 21.3 (29) | 25.9 (15) | — | .43 |
| Medicaid/Medicare | 76.5 (104) | 74.1 (43) | ||
| Self-pay | 2.2 (3) | 0 (0) | ||
| Gestational age, wks b | 38.0 (35–39) | 38.5 (37–39) | — | .32 |
| Smoking, % | 8.1 (11) | 19.0 (11) | 2.7 (1.08–6.54) | .03 |
| Nullipara, % | 30.2 (41) | 39.7 (23) | 1.5 (0.80–2.89) | .20 |
| Cesarean section, n (%) | ||||
| Primary | 47.1 (64) | 51.7 (30) | — | .31 |
| Second | 34.6 (47) | 32.8 (19) | ||
| Third | 16.9 (23) | 10.3 (6) | ||
| Fourth | 1.5 (2) | 5.2 (3) | ||
| Diabetes, % | 25.0 (34) | 41.4 (24) | 2.1 (1.10–4.06) | .02 |
| Chronic oral steroids, % | 1.5 (2) | 3.5 (2) | — | .37 c |
| Chronic hypertension, % | 39.7 (54) | 51.7 (30) | 1.6 (0.88–3.02) | .12 |
| Preeclampsia, % | 27.9 (38) | 22.4 (13) | 0.7 (0.36–1.53) | .42 |
| Induction of labor, % | 28.7 (39) | 32.8 (19) | 1.2 (0.62–2.35) | .60 |
| Labor, % | 35.3 (48) | 27.6 (16) | 0.7 (0.36–1.37) | .29 |
| Labor, h b | 9.0 (4–13) | 11.5 (6–13.5) | — | .44 |
| Ruptured membranes, % | 36.0 (49) | 32.8 (19) | 0.9 (0.45–1.66) | .66 |
| Ruptured membranes, h b | 11.0 (5–19) | 10.5 (6–16.5) | — | .92 |
| Chorioamnionitis, % | 6.6 (9) | 3.5 (2) | — | .38 c |
| Cesarean priority, % | ||||
| Nonurgent | 56.6 (77) | 58.6 (34) | — | .41 |
| Urgent | 27.9 (38) | 32.8 (19) | ||
| Emergent | 15.44 (21) | 8.6 (5) | ||
| Operative time, % | 65.0 (54–82) | 63.5 (55–90) | — | .63 |
| Vertical abdominal incision, % | 47.8 (65) | 67.2 (39) | 2.2 (1.18–4.27) | .01 |
| Subcutaneous drain, % | 28.7 (39) | 48.3 (28) | 2.3 (1.23–4.38) | .009 |
| Subcutaneous closure, % | 56.6 (77) | 48.3 (28) | 0.7 (0.39–1.33) | .29 |
| Staples skin closure, % | 48.5 (66) | 58.6 (34) | 1.5 (0.81–2.80) | .19 |
| Blood loss >1000 mL, % | 30.9 (42) | 46.6 (27) | 1.9 (1.04–3.66) | .04 |
| Blood transfusion, % | 9.6 (13) | 10.3 (6) | 1.1 (0.39–3.03) | .87 |
| Preincision antibiotic prophylaxis, % d | 66.2 (90) | 56.9 (33) | 0.7 (0.36–1.27) | .22 |
| Anticoagulation, % e | 17.0 (23) | 24.1 (14) | 1.5 (0.73–3.28) | .25 |
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