Mavra was born in Brooklyn, NY, the daughter of Regina Vogel and Harry Steinberg.  Because her parents divorced, her childhood was spent between Brooklyn and Miami Beach, Florida.  Her father, a business owner,  and her mother, who held a variety of jobs, were both immigrants to the United States in their teens.  Mavra's family was Orthodox Jewish.

After high school she first enrolled in Brooklyn College; then attended NYU for one term.  She earned her batchelors degree from Hunter in 1966; majoring in speech and theater and minoring in education. Mavra began work on her Masters in theater at Brooklyn College and  took all her courses but left before  writing her thesis because her thesis advisor was making advances. 

Mavra was a lifelong advocate for women's rights and civil rights. She worked to create opportunities and support systems for women and families. In Brooklyn, she started a free daycare center that she successfully persuaded the City of New York to fund.

She served as President of the Morris County chapter of the National Organization for Women (NOW), where she worked to advance gender equality and support women's rights at the local level. Mavra also created and produced a local television show in New Jersey called New Directions for Women, which focused on issues affecting women and gave voice to topics often overlooked in mainstream media.

Mavra was married to Robert DeRise for 32 years; and together they raised two daughters,