Many women who suffered with the symptoms of rheumatoid arthritis found that they got relief from the pain during pregnancy. It was not understood what caused this phenomenon but researchers have delved into this question and it appears they have discovered a possible mechanism that provides relief. The answer may lie in the fetus’ DNA.
There have been 2 prior studies into the relationship between fetal DNA and the improvement in the severity of the mother’s rheumatoid arthritis. As a result of technical advances scientists at the Fred Hutchinson Research Center in Seattle have been able to expand on the prior research. They studied the amount of fetal DNA in the blood of 25 pregnant women with arthritis, 19 of whom were diagnosed with rheumatoid arthritis and 6 with juvenile idiopathic arthritis (3 with polyarticular-onset, 2 with systemic-onset and 1 with oligoarticular-onset).
What they found was that there was a high level of fetal DNA in almost all of the women. Those women that had higher levels of fetal DNA experienced the most relief from their arthritis symptoms. The women who had low levels of fetal DNA experienced little or no relief. They refer to this as an inverse relationship between the level of fetal DNA in the mother’s blood and severity of the arthritis disease activity.
After 2 to 4 months had passed from delivery of their babies, almost all of the women who received relief found that their painful symptoms had returned.
Rheumatoid arthritis is marked by the body’s immune system attacking the synovial lining of the joints resulting in inflammation, pain, stiffness and loss of function. The researchers theorize that the body interprets the fetal DNA as a foreign substance. The immune system then focuses the attack on the DNA and reduces the focus on the synovial lining of the joints. Following the delivery of the baby, the level of DNA drops and the immune system again focuses on the joints.