It is, as you asked, aggravated by weight gain. Weight gain will mess with your hormone levels and push a body already pushing out weird levels of hormones further down that chaotic path. The hair growth, irregular periods, and cysts are all exacerbated with weight gain. Source: am female, have every symptom of PCOS.  I noticed during the two years where I had gained weight that the symptoms were way worse, asked my doctor, and happily found them much lessened when I lost the extra pounds. I couldn't imagine being heavily obese with PCOS.