Braekken et al (2010) Can pelvic floor muscle training reverse pelvic organ prolapse and reduce prolapse symptoms? An assessor-blinded, randomised, controlled trial. Am J Obs &Gyn. Volume 203, Issue 2, Pages 170.e1–170.e7.

The aim of this study was to investigate the effectiveness of pelvic floor muscle training in reversing pelvic organ prolapse and alleviating symptoms.
Conclusion: Pelvic floor muscle training is without adverse effects and can be used as treatment for prolapse.

Cheung RY. et al (2016) Vaginal Pessary in Women With Symptomatic Pelvic Organ Prolapse: A Randomised Controlled Trial. Obs Gyn. July;128(1) 73-80.

This study provides further evidence in nonsurgical treatment for POP. Prolapse symptoms and quality of life were improved in women using a vaginal pessary in addition to pelvic floor exercises.

Hagen S. et al (2014) Individualised pelvic floor muscle training in women with pelvic organ prolapse (POPPY): a multi-centre randomised controlled trial. The Lancet. Volume 383, No. 9919, 796–806.

One-to-one pelvic floor muscle training for prolapse is effective for improvement of prolapse symptoms. Long-term benefits should be investigated, as should the effects in specific subgroups.