pimms logo with borderFeasibility and acceptability of a brief routine weight management intervention for postnatal women embedded within the national child immunisation programme in primary care: randomised controlled cluster feasibility trial with nested qualitative study.

The PIMMS-WL trial is a randomised controlled trial currently open to recruitment.


PIMMS-WL is a randomised controlled cluster feasibility trial to assess the feasibility, acceptability and the potential for intervention contamination of a weight management intervention in women who have recently given birth. The unit of randomisation is the GP practice.

Aim of Study

The primary objective is to produce evidence that a large-scale phase III cluster RCT of a weight management intervention where women engage in managing their own weight by self-monitoring their weight and by accessing an existing online weight loss programme (Positive Online Weight Reduction; POWeR) for support is feasible. The aim of the phase III cluster RCT would be to examine the effectiveness and cost effectiveness of the intervention in facilitating long term weight loss.


The PIMMS-WL will take place within GP practices around the West Midlands.

Target population

80 women will be recruited into the trial.


PIMMS-WL is investigating two different approaches to giving women information and support on managing their weight after giving birth.

Outcome Measures 

The primary aim of the trial is to assess the feasibility of undertaking a full-scale phase III cluster trial. This decision will be based on the acceptability of the trial using a composite assessment of both quantitative and qualitative data, and will include assessment of the following:

  • whether the trial is appealing to women (via assessment of the recruitment rate to ensure a full-scale phase III trial is feasible).
  • whether the intervention is acceptable.
  • whether the intervention has any adverse impact on infant immunisation rates.
  • the number of women who complete the trial and complete the trial questionnaires.

We also wish to measure the extent of any intervention contamination, obtain data to help inform the sample size calculations for the phase III trial and assess the acceptability/validity of the ICECAP for the cost-effectiveness analysis for the phase III trial.