RA itself does not appear to affect your ability to get pregnant, although some of the medications you may be on can. If you want to get conceive and are on Methotrexate, you should get off it before you start trying - it causes severe birth defects. However, you're not necessarily left to flare while trying to get pregnant - I've heard of women being on prednisone, which may take care of your RA symptoms, but may (not always) mess with your cycle, so using a basal thermometer to check when you ovulate would probably be helpful. The good news is that most women with RA go into remission while pregnant, until about 4-6 weeks after birth. I'd suggest you discuss this with your rheumatologist - s/he'll have more information for you.