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The Midwifery and Maternity Research Unit

COSMOS: Comparing Standard Maternity Care with One to One Midwifery Support (COSMOS): A Randomised Trial

Helen McLachlan, Della Forster, Mary-Ann Davey, Michelle Newton; in collaboration with Lisa Gold, Deakin University; Mary Anne Biro, Monash University; Tanya Farrell and Jeremy Oats, Royal Women’s Hospital; Ulla Waldenström, Karolinska Institute; Leah Albers, University of New Mexico

Continuity of carer in the provision of maternity care has been strongly recommended and encouraged in Victoria and throughout Australia.  Many hospitals responded by introducing caseload midwifery, a one to one midwifery model of care in which women are cared for by a primary midwife throughout pregnancy, birth and the early postnatal period. However, this model of care had not been subjected to rigorous evaluation.

The COSMOS trial compared caseload midwifery care with the standard options of care for women at low risk of medical complications at the Royal Women’s Hospital in Melbourne. The trial which recruited over 2,300 women, found that women who were randomly allocated to receive caseload midwifery care (compared with women allocated to standard care), were less likely to have a caesarean birth, more likely to have a normal birth, and less likely to have epidural pain relief during labour. The study also found that babies of women who had caseload midwifery care were less likely to be admitted to the special care nursery or neonatal intensive care. Women allocated to caseload midwifery were also more satisfied with their care during pregnancy, birth, and after the birth in hospital and at home. They also had more positive experiences of labour and birth.

The study is the first randomised controlled trial of caseload midwifery in Australia and only the fourth internationally. It is also the largest study of its kind in the world.  The results have assisted policy-makers and maternity services in planning for future models of maternity care in Australia and Internationally.


Related publications:

  1. McLachlan H, Forster D, Davey M-AD, Lumley J, Farrell T, Oats J, Gold L, Waldenström U, Albers L, Biro MA. COSMOS: Comparing standard maternity care with one-to-one midwifery support. A randomised controlled trial. BMC Pregnancy Childbirth. 2008;8:35.
  2. McLachlan HL, Forster DA, Davey MA, Farrell T, Gold L, Biro MA, Albers L, Flood M, Oats J, Waldenström U. Effects of continuity of care by a primary midwife (caseload midwifery) on caesarean section rates in women of low obstetric risk: The COSMOS randomised controlled trial. BJOG. 2012;119(12):1483-92.
  3. Davey MA, McLachlan HL, Forster DA, Flood M. Influence of timing of admission in labour and management of labour on method of birth: Results from a RCT of caseload midwifery (COSMOS trial). Midwifery. 2013;12:1297-302.
  4. McLachlan HL, Forster DA, Davey M-A, Farrell T, Flood M, Shafiei T, Waldenström U. The effect of primary midwife-led care on women’s experience of childbirth: Results from the COSMOS randomised controlled trial. BJOG. 2016;123(3):465-74.
  5. Forster DA, McLachlan HL, Davey M-A, Biro MA, Farrell T, Gold L, Flood M, Shafiei T, Waldenström U. Continuity of care by a primary midwife (caseload midwifery) increases women's satisfaction with antenatal, intrapartum and postpartum care. The COSMOS randomised controlled trial. BMC Pregnancy Childbirth. 2016;16:28.
  6. Newton MS, McLachlan HL, Willis KF, Forster DA. Comparing satisfaction and burnout between caseload and standard care midwives: Findings from two cross-sectional surveys conducted in Victoria, Australia. BMC Pregnancy Childbirth. 2014;14:426.
  7. Dawson K, Newton MS, Forster DA, McLachlan HL. Exploring midwifery students' views and experiences of caseload midwifery: A cross sectional survey conducted in Victoria, Australia. Midwifery. 2015;31:e7–e15.
  8. Dawson K, McLachlan HL, Newton MS, Forster DA. Implementing caseload midwifery: Exploring the views of maternity managers in Australia - a national cross-sectional survey. Women Birth. 2016;29:214-222.
  9. Newton, McLachlan HL, Willis K, Forster DA. Understanding the 'work' of caseload midwives: A mixed-methods exploration of two caseload midwifery models in Victoria, Australia. Women Birth. 2016;29(3):223-233.
  10. Dawson K, Newton M, Forster D, McLachlan H. Comparing caseload and non-caseload midwives’ burnout levels and professional attitudes: A national, cross-sectional survey of Australian midwives working in the public maternity system. Midwifery. 2018;63:60-67.
  11. Dawson K, Forster DA, McLachlan HL, Newton MS. Operationalising caseload midwifery in the Australian public maternity system: Findings from a national cross-sectional survey of maternity managers. Women Birth. 2018;31(3):194-201. doi: 10.1016/j.wombi.2017.08.132.