Journal Club

Timing antibiotic prophylaxis at caesarean: Preoperatively or after cord clamping?


You are charged with formulating a local clinical policy in your hospital about antibiotic prophylaxis at caesarean sections.

Structured question

ParticipantsWomen undergoing emergency caesarean sections
 Women undergoing elective caesarean sections
InterventionA single dose of prophylactic antibiotic given preoperatively
ComparisonA single dose of prophylactic antibiotic given after cord clamping
OutcomesMaternal: febrile morbidity, endometritis, wound infection and pyelonephritis
 Neonatal: neonatal sepsis, neonatal septic work-up and neonatal intensive care unit (NICU) admission

Discussion points

  1. Background: What do current guidelines say about the above question?
  2. What would be the best primary study design to study the above question and why?
  3. Sources of bias (what is the likelihood that the reported results are true?): Critically appraise, do not simply accept on face value, the methods of this systematic review and those of its constituent studies.
  4. What is sensitivity analysis? Is the use of sensitivity analysis in this study appropriate?
  5. Findings: Using the data available, derive the relative risk reduction (RRR), absolute risk reduction (ARR) and number needed to treat (NNT) of using preoperative prophylactic antibiotics on the overall maternal infectious morbidity.
  6. Applicability of findings: Do these results overturn the existing recommendations? Would you advocate the use of a) preoperative antibiotics and b) this particular antimicrobial (a cephalosporin) based on the results of this study?


Relative risk reduction (RRR): (CER − EER)/CER CER = control group event rate

Absolute risk reduction (ARR): (CER − EER) EER = experimental group event rate

Number needed to treat (NNT): 1/ARR or 1/(CER − EER)

Suggested reading

  • National Institute for Health and Clinical Excellence. CG132: Caesarean section Section 7.6. Available from: Accessed 29 November 2012.
  • The Society of Obstetricians and Gynaecologists of Canada (SOGC). Antibiotic Prophylaxis in Obstetric Procedures. (SOGC clinical practical guideline no. 247). The Society of Obstetricians and Gynaecologists of Canada (SOGC); September 2010. Access online:
  • American College of Obstetricians and Gynecologists (ACOG). Use of prophylactic antibiotics in labor and delivery. (ACOG practice bulletin; no. 120). Washington (DC): American College of Obstetricians and Gynecologists (ACOG). June 2011. Access online:

Disclosure of interests

None declared

EYL Leunga, D Siassakosb

aWomen's Health Research Unit, Katharine Twining Network, University of London, London, UK

bSchool of Clinical Sciences, Southmead Hospital, University of Bristol, Bristol, UK. Email

For an example of how these discussion points were used for a recent #BlueJC, see BJOG Exchange in this issue. For more information see the commentary on page 657.