I've been on blood pressure tablets for over twenty-five years, including two pregnancies, never noticed any side effects. (Actually, I lie, the pills I went on during pregnancy had a distinct soporific effect, but luckily they were only for 9 months at a time.) In retrospect, I wish I'd tried harder (more exercise?) to keep off the meds, but that's just because I like to minimise the medication I'm on, not because of side effects. Do they work? Yes, for me, anyway.