The demonstration was held in Miqsha just outside Manama on Thursday after Bahrain sentenced 20 doctors to between five and 15 years in jail for their treating anti-regime protesters, Reuters reported.
The doctors, who denied the charges, were among dozens of medical staff arrested during protests, which have been raging on since February 14.
Ahlam Al-Khezaei, the head of Women's Affairs for Al Wefaq, the biggest opposition party in Bahrain, called for the release of female prisoners.
"We ask for all women prisoners to be freed and for all charges against them to be dropped. These cruel sentences of our doctors, nurses and teachers, Rola al-Safar, Jalila al-Salman and Dr. Nadi Dhaif, and everyone else," she said, referring to some of the detainees.
Bahrainis have been holding the peaceful rallies since mid-February, demanding an end to the Al Khalifa's over-40-year-long rule over the Persian Gulf island.
Scores of people have been killed and hundreds more arrested in a brutal Manama-ordered and Riyadh-backed crackdown in the country, which hosts a huge American military installation for the US Navy's Fifth Fleet in the Persian Gulf.