RE stands for Reproductive Endocrinologist. I learned the hard way that any OB/GYN can make a diagnosis and prescribe clomid, but only a few of them have the experience to deal with real fertility issues. RE's are qualified OB/GYNs but usually focus on fertility problems. I got my first PCOS diagnosis from an OB/GYN based on a single bloodtest (no u/s) and thrown onto clomid with no monitoring. I now realise that he didn't have a real clue about infertility and any doc can prescribe clomid without doing necessary investigations into the true cause of a woman's infertility.

Long-term usage of clomid seems to increase the chance of cancer in women, but this is real long-term usage (well over 12 months) that doesn't result in a pg. Usually a doc will prescribe it for four months only, as most women who will fall pg with clomid will do so within this time. However, clomid is not a miracle. It kick-starts a sluggish ovary (and can help with PCOS) but won't work for every woman plus as it is an anti-oestrogen, it can interfere with womb lining and CM and hinder a pg.

Hope this helps.