Herts & Essex Fertility Centre hired Ash following a three-way pitch. It is thought to be the first UK IVF centre to take on PR support.
Ash is charged with promoting the clinic's quality and heritage while helping to position it as the top fertility centre in the UK.
The centre has been established for nearly 20 years and has helped to deliver 3,500 babies. It treats more than 700 new couples every year.
The agency will be targeting consultants, GPs and potential patients in Herts, Essex and London.
Its main PR activity will include scientific meetings, alumni events, attendance at key healthcare professional and consumer conferences.
Ash will also promote Patient Forum quarterly educational meetings where it will have speakers on topics ranging from nutrition to relaxation techniques.
The agency will target regional, national, consumer and radio media.
The account will be headed by associate director Kelly Blaney. She said she did not believe that any other UK-based IVF clinics had made a similar move.
IVF has hit the headlines in the past two weeks as the annual meeting of the European Society of Human Reproduction and Embryology took place in Barcelona.
Headlines in the nationals included 'IVF twins not as risky as thought, say doctors' in The Guardian.
Earlier this month it was reported the world's oldest mother, aged 70, gave birth to twins using IVF treatment.