"Women with inflammatory arthritis who were currently using oral contraceptives or who had used them in the past, presented with better patient-reported outcomes within the first two years of arthritis," the study authors wrote.
Rheumatoid arthritis is an autoimmune disorder in which the body's immune system attacks the joints, resulting in pain and swelling. About 1.3 million people in the United States have rheumatoid arthritis, and of these, nearly 75 percent are women, according to the American College of Rheumatology.
Dr Waseem Mir, a rheumatologist at Lenox Hill Hospital in New York City, noted, "We have to take the findings of the study with great caution." Mir was not involved in the current study, but reviewed its findings.
One reason he cited for the note of caution is that all of the data were self-reported by patients, so it's not clear that all the participants in the study actually had rheumatoid arthritis.
Researchers only saw an association, not a cause-and-effect link, between birth control pill use and lessened rheumatoid arthritis symptoms.
Mir also pointed out the potential risks of oral contraceptives. "Certain patients with inflammatory arthritis may increase their risk of blood clots by going on oral contraceptives," Mir said.
The report was published in Arthritis Care & Research.
The researchers, led by Dr Katinka Albrecht from the German Rheumatism Research Centre in Berlin, reviewed data on 273 women with rheumatoid arthritis. The women were between 18 and 60 years old, the study said.
Less steroid treatment
The researchers found that 18 percent had never used the birth control pill, 63 percent had used it in the past, and 19 percent were taking it at the time of the study. None of the women had taken hormone replacement therapy, the study noted.
The progression of the disease was not affected by birth control use, the study found. But women who had used or were using the pill had better scores on standard measures of rheumatoid arthritis than women who had never used the pill, the researchers said.
Albrecht's group also found that women who had used or were using oral contraceptives, especially those with impaired function relied less on steroid treatment than women who hadn't used the pill.
The researchers speculated that the beneficial effect of oral contraceptives may be due to increasing the levels of oestrogen, which may have a positive effect on mood. Whether boosting oestrogen levels also helps reduce the inflammation associated with rheumatoid arthritis isn't clear, they said.
Dr Jennifer Wu, an obstetrician-gynaecologist from Lenox Hill Hospital in New York City, said, "Oral contraceptives are known to reduce the risk of ovarian and uterine cancer, and reducing the toll of rheumatoid arthritis may be another benefit."
However, she doesn't think women should be taking oral contraceptives to try to reduce or prevent rheumatoid arthritis.
Further confirmation needed
"When young women are diagnosed with rheumatoid arthritis and if they need birth control, they should think about using the birth control pill instead of other forms of birth control," Wu said.
"Older women with rheumatoid arthritis, however, shouldn't go on birth control pills to try to treat their inflammatory arthritis," she said.
Mir agreed. "Although oral contraceptives are important in society for what they offer, one should not be using it to treat inflammatory arthritis," he said.
The study authors also noted that their results should be interpreted carefully. "This association needs to be confirmed in further studies before any clinical conclusion can be drawn," they wrote.