title: A systematic review of the Robson classification for caesarean section: what works, doesn't work and how to improve it.
abstract: BACKGROUND
  Caesarean sections (CS) rates continue to increase worldwide without a clear understanding of the main drivers and consequences. The lack of a standardized internationally-accepted classification system to monitor and compare CS rates is one of the barriers to a better understanding of this trend. The Robson's 10-group classification is based on simple obstetrical parameters (parity, previous CS, gestational age, onset of labour, fetal presentation and number of fetuses) and does not involve the indication for CS. This classification has become very popular over the last years in many countries. We conducted a systematic review to synthesize the experience of users on the implementation of this classification and proposed adaptations.
  
  
  METHODS
  Four electronic databases were searched. A three-step thematic synthesis approach and a qualitative metasummary method were used.
  
  
  RESULTS
  232 unique reports were identified, 97 were selected for full-text evaluation and 73 were included. These publications reported on the use of Robson's classification in over 33 million women from 31 countries. According to users, the main strengths of the classification are its simplicity, robustness, reliability and flexibility. However, missing data, misclassification of women and lack of definition or consensus on core variables of the classification are challenges. To improve the classification for local use and to decrease heterogeneity within groups, several subdivisions in each of the 10 groups have been proposed. Group 5 (women with previous CS) received the largest number of suggestions.
  
  
  CONCLUSIONS
  The use of the Robson classification is increasing rapidly and spontaneously worldwide. Despite some limitations, this classification is easy to implement and interpret. Several suggested modifications could be useful to help facilities and countries as they work towards its implementation.
authors.affiliation: UNDP/UNFPA/UNICEF/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction, Department of Reproductive Health and Research, World Health Organization, Geneva, Switzerland.
authors.forename: Ana Pilar
authors.initials: AP
authors.lastname: Betrán
authors.affiliation: Maternal Child Clinic, Calgary, Canada.
authors.forename: Nadia
authors.initials: N
authors.lastname: Vindevoghel
authors.affiliation: Department of Social Medicine, Ribeirao Preto Medical School, University of São Paulo, Ribeirao Preto, SP, Brazil.
authors.forename: Joao Paulo
authors.initials: JP
authors.lastname: Souza
authors.affiliation: UNDP/UNFPA/UNICEF/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction, Department of Reproductive Health and Research, World Health Organization, Geneva, Switzerland.
authors.forename: A Metin
authors.initials: AM
authors.lastname: Gülmezoglu
authors.affiliation: Brazilian Cochrane Centre, São Paulo, Brazil, and Department of Internal Medicine, São Paulo Federal University, São Paulo, Brazil.
authors.forename: Maria Regina
authors.initials: MR
authors.lastname: Torloni
mesh_terms: D002585:Cesarean Section / Q000145:classification*; D005260:Female; D005843:Geography; D006287:Health Planning Guidelines; D006801:Humans