Professor Caroline Free


Primary Care and Epidemiology

Keppel Street
United Kingdom

0207958 8109

Dr Caroline Free is a Professor of Primary Care and Epidemiology at the London School of Hygiene and Tropical Medicine (LSHTM), a General Practitioner and Honorary Consultant in Sexual and Reproductive Health at Kings College Hospital. She obtained her medical degree from Leeds University, an MSc from LSHTM and PhD, focussing on contraception use, from the University of London. She worked as a clinician in rural India and continues to work in south-east London providing primary, sexual and reproductive health care to an ethnically and socio-economically mixed area of London. 


Faculty of Epidemiology and Population Health
Department of Population Health


Centre for Evaluation
Maternal, Adolescent, Reproductive & Child Health (MARCH)


Foundations for Reproductive Health, Protocol Writing, Epidemiology and Study Design MSc modules.

Co-organiser for the distance learning module protocol writing for the MSc in Clinical trials.

Member of the examinations board for the MSc in Sexual and Reproductive Health.  


Her main interest is the design, evaluation and subsequent implementation of effective primary care interventions, with a major focus on sexual and reproductive health interventions. All interventions are developed in collaboration with potential users and are based on evidence, theory, needs assessment and evidence based behaviour change approaches.

She was the principal investigator for the txt2stop trial, which was the first trial to demonstrate that smoking cessation support delivered by text message more than doubled biochemically verified smoking cessation at 6 months. Following the trial publication, she worked with the Department of Health England to develop a national service for smoking cessation support delivered by text message. Since 2012, 60,000-90,000 people have registered for the service each year. She has also worked as an advisor to the WHO m-cessation working group. Smoking cessation support delivered by text message has now been implemented in the USA, New Zealand and India, with over a million subscribers in India.  

Currently she is the principal investigator for a NIHR funded trial of a safer sex intervention delivered by mobile phone with 6250 participants in the UK- She is also working on an NIHR funded project for the development and pilot trial of a weight management after pregnancy intervention delivered by mobile phone. Other current work focusses on adherence to medication, developing and evaluating interventions to increase use of contraception and the evaluation of a web based sexual and reproductive health service. She is an advisor to WHO M-health working groups for non-communicable disease and maternal, reproductive, neonatal, and child health. 

Research Area
Clinical trials
Health promotion
Primary care
Sexual health
Behaviour change
Mixed methods
Mobile technologies
Reproductive health
Disease and Health Conditions
Sexually transmitted disease
Non-communicable diseases
Sexually transmitted infection
United Kingdom

Selected Publications

Comparing the characteristics of users of an online service for STI self-sampling with clinic service users: a cross-sectional analysis.
Barnard, S. ; Free, C. ; Bakolis, I. ; Turner, K.M.E. ; Looker, K.J. ; Baraitser, P. ;
Sex Transm Infect
eSexual health interventions: promising, but more evidence needed.
Wellings, K. ; Mehl, G.L. ; Free, C.J. ;
Lancet Public Health
Internet-accessed sexually transmitted infection (e-STI) testing and results service: A randomised, single-blind, controlled trial.
Wilson, E. ; Free, C. ; Morris, T.P. ; Syred, J. ; Ahamed, I. ; Menon-Johansson, A.S. ; Palmer, M.J. ; Barnard, S. ; Rezel, E. ; Baraitser, P. ;
PLoS Med
Can text messages increase safer sex behaviours in young people? Intervention development and pilot randomised controlled trial.
Free, C. ; McCarthy, O. ; French, R.S. ; Wellings, K. ; Michie, S. ; Roberts, I. ; Devries, K. ; Rathod, S. ; Bailey, J. ; Syred, J. ; Edwards, P. ; Hart, G. ; Palmer, M. ; Baraitser, P. ;
Health Technol Assess
Mobile phone-based interventions for improving contraception use.
Smith, C. ; Gold, J. ; Ngo, T.D. ; Sumpter, C. ; Free, C. ;
Cochrane Database Syst Rev
Effect of a mobile phone-based intervention on post-abortion contraception: a randomized controlled trial in Cambodia.
Smith, C. ; Ngo, T.D. ; Gold, J. ; Edwards, P. ; Vannak, U. ; Sokhey, L. ; Machiyama, K. ; Slaymaker, E. ; Warnock, R. ; McCarthy, O. ; Free, C. ;
Bull World Health Organ
The effectiveness of mobile-health technology-based health behaviour change or disease management interventions for health care consumers: a systematic review.
Free, C. ; Phillips, G. ; Galli, L. ; Watson, L. ; Felix, L. ; Edwards, P. ; Patel, V. ; Haines, A. ;
PLoS Med
Smoking cessation support delivered via mobile phone text messaging (txt2stop): a single-blind, randomised trial.
Free, C. ; Knight, R. ; Robertson, S. ; Whittaker, R. ; Edwards, P. ; Zhou, W. ; Rodgers, A. ; Cairns, J. ; Kenward, M.G. ; Roberts, I. ;
See all Professor Caroline Free's Publications