Obesity is a common, serious health condition that poses major health risks to individuals and increases costs to society. It is estimated that 97 million adults in the United States are obese as defined as body mass index 30 or greater and approximately one-third of childbearing-age women in the United States are obese [
As is true for any abdominal surgery, cesarean delivery presents clear challenges in obese women. In pelvic surgery, low transverse or Pfannenstiel skin incisions give adequate exposure while providing a good cosmetic result [
Hospital records of all pregnant women with a body mass index greater than 40 kg/m2 who underwent cesarean delivery from January 2007 to January 2011 were reviewed after approval from The University of Tennessee Health Science Center Institutional Review Board. Both dictated and written operative reports were used to identify the types of uterine and skin incisions. Our cohort included all patients who underwent supraumbilical vertical skin incisions. Patients who underwent Pfannenstiel incisions comprised controls. The control participants were selected chronologically; cohort and controls were matched at a 1 : 2 ratio.
Our primary outcome was the occurrence of classical hysterotomy. Assuming a prevalence of the primary outcome of 5% in the control group and considering a power of 80% and 2-sided alpha = 0.05, we estimated that a sample size of 34 subjects in each group was required for a 7-fold increase in the primary outcome among women undergoing supraumbilical vertical incisions. We also investigated the following secondary outcomes: wound complications (a composite of superficial and deep surgical site infection, wound dehiscence, or return to the operating room to address the wound), need for transfusion, postoperative length of stay more than 3 days, total minutes of surgery, drain placement, endomyometritis, and estimated blood loss of more than 1000 mL. Potential confounding variables included age, body mass index, preexisting maternal diseases, number of previous abdominal surgeries, use of surgical drains, use of preoperative antibiotics, and gestational age at delivery.
Data analysis was performed using SAS 9.3 (SAS Institute Inc., Cary, NC). Two-sample
During the study period, 45 women delivered infants through a supraumbilical vertical incision. Two women were excluded from the cohort group due to incomplete records. Patient demographics are listed in Table
Demographics.
Characteristics | Supraumbilical |
Pfannenstiel |
|
---|---|---|---|
Age |
|
|
<.0001 |
Average body mass index |
|
|
<.0001 |
Gestation at delivery |
|
|
.0015 |
African American | 37 (86%) | 77 (86%) | .6655 |
Diabetes | 21 (49%) | 8 (9%) | <.0001 |
Hypertension | 23 (53%) | 39 (43%) | .2722 |
Preeclampsia | 19 (44%) | 31 (34%) | .2780 |
Tobacco use | 4 (9%) | 10 (11%) | 1.0000 |
Previous abdominal surgery | 21 (49%) | 44 (49%) | .9956 |
Classical uterine incision was more prevalent in women who had a supraumbilical skin incision compared to controls (Pfannenstiel incision) (OR, 24.6; 95% CI, 9.0–66.8). Drain placement (OR, 6.5; 95% CI, 2.6–16.2) and estimated blood loss greater than 1000 mL (OR, 3.4; 95% CI, 1.4–8.4) occurred more frequently in women with supraumbilical incisions. Total operative time was longer among those who had a supraumbilical skin incision compared to controls (97 minutes versus 68 minutes,
Outcomes.
Outcome | Supraumbilical |
Pfannenstiel |
OR | 95% CI |
|
---|---|---|---|---|---|
Classical hysterotomy | 29 (67%) | 7 (8%) | 24.6 | 9.0–66.8 | <.0001 |
Wound complication | 8 (19%) | 7 (8%) | 2.7 | .9–8.0 | .0811 |
Blood transfusion | 7 (16%) | 5 (6%) | 3.3 | .98–11.1 | .0557 |
Length of stay >3 days | 33 (77%) | 59 (66%) | 1.7 | .8–4.0 | .1912 |
Endomyometritis | 2 (5%) | 2 (2%) | 2.1 | .3–15.8 | .5945 |
Drain placed | 18 (42%) | 9 (10%) | 6.5 | 2.6–16.2 | <.0001 |
Estimated blood loss >1 liter | 14 (33%) | 11 (12%) | 3.4 | 1.4–8.4 | .0055 |
Total minutes of surgery |
|
|
<.0001 |
After adjusting with multivariate analysis for confounders (age, body mass index, gestational age at delivery, diabetes, tobacco use, and use of a surgical drain), supraumbilical incision remained as an independent significant risk factor for undergoing classical hysterotomy, placement of a surgical drain, estimated blood loss more than 1000 mL, and longer operative time (Table
Multivariate regression analysis.
Outcome | OR | 95% CI |
|
---|---|---|---|
Classical hysterotomy | 15.8 | 4.1, 60.8 | <.0001 |
Drain | 7.8 | 2.3, 26.7 | .0010 |
Estimated blood loss >1 liter | 6.4 | 2.0, 20.1 | .0022 |
Total minutes of surgery | Slope = 27.5 | .0011 |
Variables controlled for include age, body mass index, gestational age at delivery, and diabetes mellitus.
Women with a body mass index greater than 40 kg/m2 who have a supraumbilical vertical skin incision at the time of cesarean are more likely to undergo a classical hysterotomy than those who have a Pfannenstiel incision. Supraumbilical incisions are also associated with a greater risk of placement of a surgical drain, estimated blood loss more than 1000 mL, and longer operative times when compared to Pfannenstiel skin incisions.
One of the strengths of this study is the number of patients derived from a single institution over a relatively short period of time; this may limit the possibility of different techniques and postoperative care practices. The limitations of our study are those inherent to retrospective designs. Our cohort subjects differed significantly from controls in age and prevalence of higher body mass index and diabetes; however, after adjusting for these and other confounders, our results showed that supraumbilical incision was an independent risk factor that led to classical hysterotomy incision. There is also potential of referral bias given that all the patients in this study were from one regional perinatal center. The majority of the patients was of African American ancestry and had public insurance, which could limit the external validity of the study.
Our findings agree with those reported by other investigators. Alanis et. al. showed that women with body mass index greater than 40 kg/m2 with vertical skin cesarean incisions were more likely to undergo classical hysterotomy; however, they did not differentiate between supraumbilical and infraumbilical vertical incisions [
The morbidity associated with classical cesarean delivery and women with a prior classical hysterotomy has been widely reported [
In conclusion, supraumbilical vertical approach in women with body mass index greater than 40 kg/m2 undergoing cesarean section is associated with higher rate of classical hysterotomy, greater blood loss, and longer operative time when compared to Pfannenstiel incisions. The importance of these findings allows clinicians to properly counsel these women who undergo cesarean delivery.