My Daughter Is On A Pill Called 'Estelle' Mainly For

My Daughter is on a Pill called 'Estelle' mainly for her skin, which, after 2-3 months finally seems to be working and her skin has cleared up beautifully, however, she has gained weight, not a lot but enough to make a 21 year old girl feel in her words ‘fat’. She is about 165cm tall and currently weighs 56kg which is the most she has ever weighed. Could the pill have something to do with it, I think I recall putting a bit of weight on around the same age, so maybe it is just the age too?