Can pregnancy cause rheumatoid arthritis?

Q) I read with interest the question and answer about why rheumatoid arthritis improves in pregnancy. I've been wondering about a related problem since I developed a rheumatoid condition soon after I gave birth. I've since discovered many women who've had a similar experience after childbirth and I was wondering whether there has been any research done in this area as it seems to me that in the same way the immune system is switched off during pregnancy, it's possible that it's over-activated when it all comes back. My condition has finally gone into remission five years after my son’s birth with the aid of methotrexate.
Christine Barrie, Cambridge (Autumn 2010)

A) Yes, relapse after pregnancy, and new onset rheumatoid arthritis after giving birth, are both well recognised. That's why we take appropriate measures to restart any necessary treatments as soon as possible after the delivery. Clearly, there are big changes occurring in the body and the immune system during pregnancy, and it's possible that these huge swings leave the woman vulnerable to auto-immune disorders such as rheumatoid arthritis.