menstrual disorders
"I started my periods at about 12 and it was hell : heavy, painful, unpredictable. Started this pill at about 14 and it was a  godsend (so to speak...). A couple of years on, new GP didn't check my age before seeing me and upped my prescription to a stronger pill. Period was late, painful and strangely coloured, acne started acting up and I was emotional. I went back and begged (crying...) another GP to put me back on loestrin. She was mystified as to why it was changed in the first place. Everything immediately went back to normal. I'm still on it now, 4 years later and have not encountered any side-effects."