[1] At the age of 23, Mears moved to London and became the operator of a vacant practice of a male doctor, at a time when most men general practitioners were enlisted for the war effort.
[2][5] Mears did not formally qualify to become a gynaecologist and was privately not agreeable to the surgical emphasis of a branch of medicine that was dominated by men.
[5] Mears established the Christchurch Marriage Guidance Council with two woman colleagues,[1] and helped to set up the city's Family Planning Association.
[1] Mears returned to Britain in 1956, exchanging practices for four months with fellow gynaecologist Joan Malleson, to broaden her professional opportunities.
[3] She became head of research into all oral (and subsequently) inter-urine contraceptives, coordinating and observing every clinical trial conducted by pharmaceutical companies in the United Kingdom.
[5][4] Mears prescribed the drug Conovid to patients, believing that women should have the right to have control of their fertility and promoted oral contraceptives despite vocal opposition from her profession from individuals such as Edith Summerskill.
[1][3] She campaigned through the media for reform to laws regarding abortion that was put through Parliament by Edwin Brooks and David Steel in the late 1960s and, unsuccessfully, euthanasia.
[3][4] Mears later opened consulting rooms in Harley Street and moved to Grimsby from where she operated a clinic for psycho sexual problems on behalf of the Lincolnshire Health Authority.