Cesarean sections - based on the evidence

Cesarean section is the most commonly performed surgical procedure in the United States, with nearly 1.3 million cases performed each year. After rising for several decades, the cesarean rate has plateaued at approximately 32% of all deliveries.¹ Some portions of the procedure have been thoroughly investigated in the literature, while others have not. The purpose of this article is to review the steps in a cesarean delivery and examine the best available evidence for performing the procedure.

Skin preparation

Surgical site infections (SSIs) add significantly to a patient’s cost of care. Cesarean sections are associated with a 10-fold increased risk of infection as compared to vaginal delivery.² Abdominal preparations with a bactericidal solution have been shown to decrease the risk of a SSI. The preparations come in a variety of types, but the most commonly studied are povidone-iodine (PI), PI-alcohol, and chlorhexidine gluconate (CHG)-alcohol.    

In 2012, a Cochrane Review³ found insufficient evidence to recommend one skin preparation over another, but at that time data in obstetrics were lacking. Huang et al⁴ performed a more recent meta-analysis comparing CHG versus PI preparations, both with and without alcohol, and found no difference in SSI rates. This was supported in a subgroup analysis comparing CHG-alcohol versus PI-alcohol (RR 0.59, CI 0.33-1.06). Individual studies, however, varied in both concentration of the preparation and presence of other agents, such as isopropyl alcohol. They also noted a lack of quality studies.        

In 2016, Tuuli et al⁵ randomized patients undergoing cesarean deliveries to PI-alcohol or CHG-alcohol. There were significantly lower SSI rates in the CHG group (RR = 0.55; CI 0.34-0.90). Unlike prior studies, this study included unscheduled cesarean deliveries (42%), improving the generalizability of the results. In general, CHG-alcohol solutions have been shown to decrease SSI rates in a variety of surgeries; based on these studies and the results of Tuuli’s trial, CHG-alcohol skin preps are a reasonable first choice for obstetrical patients. Of note, alcohol-containing skin preps require 3 minutes of drying time to avoid the flammability that may occur prior to evaporation, whereas preparations without alcohol can be used immediately without a “dry time.” The methods of application are different and the manufacturers’ instructions should be followed for proper application.

Vaginal preparation before cesarean delivery

Vaginal preparation with bactericidal solutions has been studied as a mechanism to reduce infectious morbidity after cesarean delivery. Vaginal cleansing with PI has been shown to significantly reduce incidence of endometritis by over 50%.⁶ This was even more pronounced for women in labor or with ruptured membranes at the time of cesarean. These findings were supported in a 2017 meta-analysis of studies using either a PI- or CHG-based vaginal prep, which found a reduction in endometritis and postoperative fever with vaginal preparation (RR 0.52, CI 0.28-0.97), even more so in women laboring or with ruptured membranes (RR 0.23, CI 0.10-0.52).⁷

Whether this translates to benefit in non-laboring or unruptured patients is less clear. Furthermore, many of the studies included in this meta-analysis excluded patients with chorioamnionitis or included patients who received antibiotics after cord clamping, a practice known to increase SSI risk. Lastly, it is unknown how vaginal preparation may impact the vaginal microbiome and infant health. More data from a modern setting-incorporating current skin preparation solutions and antibiotic administration practices-are needed to fully evaluate the potential impact of vaginal cleansing.

Antibiotic administration

Cesarean delivery is the single most important risk factor for maternal postpartum infection. While antibiotic prophylaxis is recommended, the timing, dose, agents, and use of post-delivery antibiotics have all been recently investigated. Originally, prophylaxis was given after umbilical cord clamping because of the potential concern for masking neonatal sepsis or infection. Several large studies evaluating antibiotic prophylaxis administered after cord clamping versus at the time of skin incision, however, found a reduced incidence of infectious morbidity when antibiotics were given within the 60 minutes preceding the skin incision. In 2011, The American College of Obstetricians and Gynecologists (ACOG) (Practice Bulletin #120) recommended pre-incision antibiotic administration as routine practice.⁸

Extended spectrum antibiotics that have coverage against gram-positive, gram-negative, and some anaerobes are appropriate for prophylaxis given the multiple organisms that have been implicated in SSIs. Cefazolin, a first-generation cephalosporin, is most commonly chosen. A combination of clindamycin and an aminoglycoside can be used for women with significant penicillin allergies.

The C-SOAP trial⁹ was a multicenter study that randomized 2013 women undergoing cesarean delivery during labor or after membrane rupture to an additional 500 mg azithromycin or placebo to their standard antibiotic prophylaxis. A 50% reduction in postoperative SSI was demonstrated with the addition of azithromycin (Figure 1). Furthermore, a cost-effectiveness model using an azithromycin-cephalosporin combination for cesarean prophylaxis found it to be cost-effective, leading to improved maternal outcomes beyond a reduction in SSI, including fewer cases of sepsis, venous thromboembolism, and future uterine ruptures.¹⁰ Adding azithromycin to the standard antibiotic prophylaxis in women undergoing cesarean who are laboring or with ruptured membranes may be warranted.

Obesity is a known risk factor for SSI. Given the different pharmacokinetics in obese women, a higher dose of antibiotics may be indicated in women with body mass index greater than 30 kg/m2 or absolute weight of more than 100 kg.⁸

Abdominal incisions

Most cesarean sections are performed using the Pfannenstiel skin incision, which has been associated with better wound healing and decreased postoperative pain compared to vertical skin incisions. The Joel-Cohen incision has been described as an alternative.¹¹ It is a straight incision, versus the slightly curved Pfannenstiel, and is located 3 cm below the anterior superior iliac spines. The subcutaneous tissue layer is only opened sharply 2 to 3 cm in the midline down to the fascia. The incision is then stretched transversely using blunt dissection. Entry into the peritoneum occurs bluntly in a cranial to caudal fashion.

The Joel-Cohen technique was found to decrease all of the following when compared to the Pfannenstiel incision: time to delivery, overall operating room time, blood loss, and postoperative pain medication requirements.¹² There were no differences regarding wound infection, blood transfusions or muscle strength 3 months after delivery. There are a number of Joel-Cohen-related techniques described in the literature, all of which share the common theme of limited dissection of the existing tissue in favor of bluntly developing surgical planes.

Bladder flap

Creating a bladder flap is a vestige of prior times, when it could be used to isolate the hysterotomy from the peritoneal cavity to decrease risk of infection. In clinical trials with modern antibiotic use, however, routine creation of a bladder flap has not demonstrated any benefit, although it does increase operative time.¹³ In certain specific situations (e.g., repeat cesarean with significant adhesive disease, suspected placenta accreta), use of a bladder flap may facilitate access to the lower uterine segment. It is unnecessary, though, as a routine measure.

Uterine incision

Typically, hysterotomy is created in a transverse fashion through the lower uterine segment, given the increased risk of uterine rupture associated with classical cesareans. After uterine entry, the hysterotomy may be extended bluntly or sharply, most often with bandage scissors. Blunt dissection has been found to result in a quicker extension, less risk of inadvertent neonatal injury, and lower blood loss.¹⁴ Whether to extend the hysterotomy with transverse manual traction versus cephalo-caudad manual traction has also been evaluated.¹⁵ Transverse extensions resulted in a higher rate of unintended extensions laterally (and potentially into the uterine artery) and greater blood loss. Altogether, these data support blunt extension of the uterine incision in a cephalo-caudad direction.

Placental delivery

After fetal delivery, the placenta should typically be allowed to deliver spontaneously. A Cochrane review in 2008 found higher rates of endometritis, blood loss, and greater drops in hematocrit with manual extraction.¹⁶ Spontaneous placental delivery allows uterine contraction to limit blood loss from the dilated uterine sinuses supplying the placenta.

Uterine repair

Hysterotomies may be closed in a variety of fashions, but most often in single or multiple layers. Single-layered closure has consistently shown beneficial results for short-term outcomes such as decreased blood loss, operative time, and postoperative pain.¹⁷ However, single-layer closure may present a risk factor for uterine rupture during a future trial of labor after cesarean delivery.¹⁸ Interestingly, Roberge et al¹⁹ did not find increased rates of uterine rupture between a single or double-layered closure. Instead, they found that a locking, single-layered closure increased risk of uterine rupture when compared to an unlocked, single-layered closure. Given these data, it may be the locked nature of the suture, possibly strangulating the tissue, which increases risk of future uterine rupture. In a setting where vaginal birth after cesarean (VBAC) is uncommon, a single-layer closure is likely adequate, but the authors recommend a double-layer closure in a patient considering VBAC in the future.

Given a lack of data regarding the choice of suture material, it is reasonable to select a suture type based on the surgeon’s preference.

Peritoneal closure

Adhesion formation can complicate future cesarean deliveries, resulting in prolonged surgical time, increased blood loss, or visceral injury. The role of peritoneal closure in prevention of adhesion formation, though, remains unclear. While observational studies suggest that closure of the parietal peritoneum may play a role in adhesion prevention,²⁰ prospective studies randomizing patients to closure versus non-closure of the parietal peritoneum do not seem to show a benefit when adhesions are evaluated at the time of subsequent cesarean delivery.²¹ Further study is needed before recommending routine closure of the peritoneum.

Adhesion barriers

Adhesion barriers, such as sodium hyaluronic acid/carboxymethylcellulose, may also prevent adhesion formation. However, randomized trials in obstetrics have not demonstrated benefit when used at time of cesarean delivery.^22,23 Given the expense of these adhesion barrier products and without evidence of proven benefit, we advocate against their routine use.

Subcutaneous closure

Based upon a meta-analysis performed in 2004, subcutaneous tissue should be closed if the thickness is greater than 2 cm.²⁴ That analysis demonstrated a 34% decreased risk of wound disruption when subcutaneous tissue greater than 2 cm was closed. The subcutaneous tissue may be closed with either a continuous suture or interrupted sutures, based on the surgeon’s preference. There appears to be no additional benefit to wound healing for routine placement of a subcutaneous drain.²⁵

Skin closure

Skin closure technique was evaluated in a 2013 randomized controlled trial comparing subcuticular suture and skin staples, which found a decreased incidence of wound complications associated with use of suture.²⁶ Use of subcuticular skin closure was further supported by a 2015 meta-analysis revealing an overall RR of 0.49 (CI 0.28-0.87) for wound complications in the suture group.²⁷

Suture material has also been a recent area of study. Buresch et al²⁸ randomized women to undergo closure of skin with poliglecaprone 25 (Monocryl™) versus polyglactin 910 (Vicryl™) and found lower rates of wound complications associated with the former. This study, however, did not include emergent cesarean deliveries and the specific antiseptic skin preparation was not identified, which may limit generalizability of the results. This is a topic of ongoing research.

Obesity is a known risk factor for wound infections. Negative-pressure wound therapy after cesarean may be associated with reduced risk of surgical site infections, but larger trials are needed to clarify their benefit in this population.²⁹

Conclusion

Based on recent trials and meta-analyses, a number of recommendations can be made regarding routine performance of cesarean delivery (Table 1). As in any area of medicine, clinical scenarios may dictate a particular approach and cause a practitioner to deviate from the “standard” approach (for example, creating a bladder flap when faced with dense lower-uterine segment adhesions). An increased research focus, however, allows us to continue refining our surgical technique for this common obstetrical intervention. 

Disclosures The authors report no potential conflicts of interest with regard to this article.

1. Martin JA, Hamilton BE, Osterman MJ. Births in the United States, 2015. Natl Center Health Stat Data Br. 2016;2015:1-8.

2. Burrows LJ, Meyn LA, Weber AM. Maternal morbidity associated with vaginal versus cesarean delivery. Obstet Gynecol. 2004;May103(5 Pt 1):907-12.

3. Webster J, Osborne S. Preoperative bathing or showering with skin antiseptics to prevent surgical site infection. Cochrane Database Syst Rev. 2012 Feb 20;2:CD004985.

4. Huang H, Li G, Wang H, He M. Optimal skin antiseptic agents for prevention of surgical site infection in cesarean section: a meta-analysis with trial sequential analysis. J Matern Fetal Neonatal Med. 2017;Aug 30:1-8.

5. Tuuli MG, Liu J, Stout MJ, et al. A randomized trial comparing skin antiseptic agents at cesarean delivery. N Engl J Med. 2016;374(7):1-9.

6. Haas DM, Morgan S, Contreras K. Vaginal preparation with antiseptic solution before cesarean section for preventing postoperative infections. Cochrane Database Syst Rev. 2014;Dec 21(12CD007892).

7. Caissutti C, Saccone G, Zulio F, et al. Vaginal cleansing before cesarean delivery: a systematic review and meta-analysis. Obstet Gynecol. 2017;130(3):527-538.

8. ACOG Practice Bulletin No. 120: Use of prophylactic antibiotics in labor and delivery. Obstet Gynecol. 2011;117(6):1472-83.

9. Tita AT, Szychowski JM, Boggess K, et al and C/SOAP Trial Consortium. Adjunctive azithromycin prophylaxis for cesarean delivery. N Engl J Med. 2016;375(13):1231-41.

10. Skeith AE, Niu B, Valent AM, Tuuli MG, Caughey AB. Adding azithromycin to cephalosporin for cesarean delivery infection prophylaxis: a cost-effectiveness analysis. Obstet Gynecol. 2017;130(6):1279-84.

11. Wallin G, Fall O. Modified Joel-Cohen technique for caesarean delivery. BJOG. 1999;106:221-226.

12. Mathai M, Hofmeyr GH, Mathai NE. Abdominal surgical incisions for caesarean section. Cochrane Syst Rev. 2013;May 31;(5):CD004453.

13. Tuuli MG, Odibo AO, Gogertey P, Roehl K, Stamilio D, Macones GA. Utility of the bladder flap at cesarean delivery: a randomized controlled trial. Obstet Gynecol. 2012;119(4):815-21.

14. Magann EF, Chauhan SP, Bufkin L, Field K, Roberst WE, Martin JN Jr. Intra-operative Haemorrhage by blunt versus sharp expansion of the uterine incision at cesarean delivery: a randomized clinical trial. BJOG. 2002;109(4):448-52.

15. Cromi A, Ghezzi F, Di Naro E, Siesto G, Loverro G, Bolis P. Blunt expansion of the low transverse uterine incision at cesarean delivery: a randomized comparison of 2 techniques. Am J Obstet Gynecol. 2008;199(3):292 e1-6.

16. Anorlu RI, Maholwana B, Hofmeyr GJ. Methods of delivering the placenta at caesarean section. Cochrane Database Syst Rev. 2008 Jul 16;(3):CD004737.

17. Dodd JM, Anderson ER, Gates S, Grivell RM. Surgical techniques for uterine incision and uterine closure at the time of cesarean section. Cochrane Database Syst Rev. 2014 Jul 22;(7):CD004732.

18. Gyamfi C, Juhasz G, Gyamfi P, Blumenfeld Y, Stone JL. Single- versus double-layer uterine incision closure and uterine rupture. J Matern Fetal Neonatal Med. 2006;19(10):639-43.

19. Roberge S, Chaillet N, Boutin A, et al. Single- versus double-layer closure of the hysterotomy incision during cesarean delivery and risk of uterine rupture. Int J Gynaecol Obstet. 2011;115(1):5-10.

20. Lyell DJ, Caughey AB, Hu E, Daniels K. Peritoneal closure at primary cesarean delivery and adhesions. Obstet Gynecol. 2005;106(2):275-80.

21. Kapustian V, Anteby EY, Gdalevich M, Shenhav S, Lavie O, Gemer O. Effect of closure versus nonclosure of peritoneum at cesarean section on adhesions: a prospective randomized study. Am J Obstet Gynecol. 2012;206(1):56.e1-4.

22. Kiefer DG, Muscat JC, Santorelli J, et al. Effectiveness and short-term safety of modified sodium hyaluronic acid-carnoxymethylcellulose at cesarean delivery: a randomized trial. Obstet Gynecol. 2016;214(3):373.e1-373.e12.

23. Gaspar-Oishi M Aeby T. Cesarean delivery times and adhesion severity associated with prior placement of a sodium hyaluronate-carboxycellulose barrier. Obstet Gynecol. 2014;124(4):679-83.

24. Chelmow D, Rodriguez EJ, Sabatini MM. Suture closure of subcutaneous fat and wound disruption after cesarean delivery: a meta-analysis. Obstet Gynecol. 2004;103(5 Pt 1):974-80.

25. Ramsey PS, White AM, Guinn DA, et al. Subcutaneous tissue reapproximation, alone or in combination with drain, in obese women undergoing a cesarean delivery. Obstet Gynecol. 2005;105(5 Pt 1):967-73.

26. Figueroa D, Jauk VC, Szychowski JM et al. Surgical staples compared with subcuticular suture for skin closure after cesarean delivery: a randomized controlled trial. Obstet Gynecol. 2013;121(1):33-8.

27. Mackeen AD, Schuster M, Berghella V. Suture versus staples for skin closure after cesarean section: a metaanalysis. Am J Obstet Gynecol. 2015;212(5):621.e1-10.

28. Buresch AM, Van Arsdale A, Ferzli, M, et al. Comparison of subcuticular suture type for skin closure after cesarean delivery: a randomized controlled trial. Obstet Gynecol. 2017;130(3):521-26.

29. Yu L, Kronen RJ, Simon LE, Stoll CRT, Colditz GA, Tuuli MG. Prophylactic negative-pressure wound therapy after cesarean is associated with reduced risk of surgical site infection: a systematic review and meta-analysis. Am J Obstet Gynecol. 2017;Sep 23.pii: S0002-9378(17)31132-8.[Epub ahead of print].

Disclosures:

The authors report no potential conflicts of interest with regard to this article.

References:

1. Martin JA, Hamilton BE, Osterman MJ. Births in the United States, 2015. Natl Center Health Stat Data Br. 2016;2015:1-8.

2. Burrows LJ, Meyn LA, Weber AM. Maternal morbidity associated with vaginal versus cesarean delivery. Obstet Gynecol. 2004;May103(5 Pt 1):907-12.

3. Webster J, Osborne S. Preoperative bathing or showering with skin antiseptics to prevent surgical site infection. Cochrane Database Syst Rev. 2012 Feb 20;2:CD004985.

4. Huang H, Li G, Wang H, He M. Optimal skin antiseptic agents for prevention of surgical site infection in cesarean section: a meta-analysis with trial sequential analysis. J Matern Fetal Neonatal Med. 2017;Aug 30:1-8.

5. Tuuli MG, Liu J, Stout MJ, et al. A randomized trial comparing skin antiseptic agents at cesarean delivery. N Engl J Med. 2016;374(7):1-9.

6. Haas DM, Morgan S, Contreras K. Vaginal preparation with antiseptic solution before cesarean section for preventing postoperative infections. Cochrane Database Syst Rev. 2014;Dec 21(12CD007892).

7. Caissutti C, Saccone G, Zulio F, et al. Vaginal cleansing before cesarean delivery: a systematic review and meta-analysis. Obstet Gynecol. 2017;130(3):527-538.

8. ACOG Practice Bulletin No. 120: Use of prophylactic antibiotics in labor and delivery. Obstet Gynecol. 2011;117(6):1472-83.

9. Tita AT, Szychowski JM, Boggess K, et al and C/SOAP Trial Consortium. Adjunctive azithromycin prophylaxis for cesarean delivery. N Engl J Med. 2016;375(13):1231-41.

10. Skeith AE, Niu B, Valent AM, Tuuli MG, Caughey AB. Adding azithromycin to cephalosporin for cesarean delivery infection prophylaxis: a cost-effectiveness analysis. Obstet Gynecol. 2017;130(6):1279-84.

11. Wallin G, Fall O. Modified Joel-Cohen technique for caesarean delivery. BJOG. 1999;106:221-226.

12. Mathai M, Hofmeyr GH, Mathai NE. Abdominal surgical incisions for caesarean section. Cochrane Syst Rev. 2013;May 31;(5):CD004453.

13. Tuuli MG, Odibo AO, Gogertey P, Roehl K, Stamilio D, Macones GA. Utility of the bladder flap at cesarean delivery: a randomized controlled trial. Obstet Gynecol. 2012;119(4):815-21.

14. Magann EF, Chauhan SP, Bufkin L, Field K, Roberst WE, Martin JN Jr. Intra-operative Haemorrhage by blunt versus sharp expansion of the uterine incision at cesarean delivery: a randomized clinical trial. BJOG. 2002;109(4):448-52.

15. Cromi A, Ghezzi F, Di Naro E, Siesto G, Loverro G, Bolis P. Blunt expansion of the low transverse uterine incision at cesarean delivery: a randomized comparison of 2 techniques. Am J Obstet Gynecol. 2008;199(3):292 e1-6.

16. Anorlu RI, Maholwana B, Hofmeyr GJ. Methods of delivering the placenta at caesarean section. Cochrane Database Syst Rev. 2008 Jul 16;(3):CD004737.

17. Dodd JM, Anderson ER, Gates S, Grivell RM. Surgical techniques for uterine incision and uterine closure at the time of cesarean section. Cochrane Database Syst Rev. 2014 Jul 22;(7):CD004732.

18. Gyamfi C, Juhasz G, Gyamfi P, Blumenfeld Y, Stone JL. Single- versus double-layer uterine incision closure and uterine rupture. J Matern Fetal Neonatal Med. 2006;19(10):639-43.

19. Roberge S, Chaillet N, Boutin A, et al. Single- versus double-layer closure of the hysterotomy incision during cesarean delivery and risk of uterine rupture. Int J Gynaecol Obstet. 2011;115(1):5-10.

20. Lyell DJ, Caughey AB, Hu E, Daniels K. Peritoneal closure at primary cesarean delivery and adhesions. Obstet Gynecol. 2005;106(2):275-80.

21. Kapustian V, Anteby EY, Gdalevich M, Shenhav S, Lavie O, Gemer O. Effect of closure versus nonclosure of peritoneum at cesarean section on adhesions: a prospective randomized study. Am J Obstet Gynecol. 2012;206(1):56.e1-4.

22. Kiefer DG, Muscat JC, Santorelli J, et al. Effectiveness and short-term safety of modified sodium hyaluronic acid-carnoxymethylcellulose at cesarean delivery: a randomized trial. Obstet Gynecol. 2016;214(3):373.e1-373.e12.

23. Gaspar-Oishi M Aeby T. Cesarean delivery times and adhesion severity associated with prior placement of a sodium hyaluronate-carboxycellulose barrier. Obstet Gynecol. 2014;124(4):679-83.

24. Chelmow D, Rodriguez EJ, Sabatini MM. Suture closure of subcutaneous fat and wound disruption after cesarean delivery: a meta-analysis. Obstet Gynecol. 2004;103(5 Pt 1):974-80.

25. Ramsey PS, White AM, Guinn DA, et al. Subcutaneous tissue reapproximation, alone or in combination with drain, in obese women undergoing a cesarean delivery. Obstet Gynecol. 2005;105(5 Pt 1):967-73.

26. Figueroa D, Jauk VC, Szychowski JM et al. Surgical staples compared with subcuticular suture for skin closure after cesarean delivery: a randomized controlled trial. Obstet Gynecol. 2013;121(1):33-8.

27. Mackeen AD, Schuster M, Berghella V. Suture versus staples for skin closure after cesarean section: a metaanalysis. Am J Obstet Gynecol. 2015;212(5):621.e1-10.

28. Buresch AM, Van Arsdale A, Ferzli, M, et al. Comparison of subcuticular suture type for skin closure after cesarean delivery: a randomized controlled trial. Obstet Gynecol. 2017;130(3):521-26.

29. Yu L, Kronen RJ, Simon LE, Stoll CRT, Colditz GA, Tuuli MG. Prophylactic negative-pressure wound therapy after cesarean is associated with reduced risk of surgical site infection: a systematic review and meta-analysis. Am J Obstet Gynecol. 2017;Sep 23.pii: S0002-9378(17)31132-8.[Epub ahead of print].