What was involved in the most recent study?
The study itself looked at 2,578 women with rheumatoid arthritis and 4,129 women without RA (the control group). The study focused on women in Sweden who were over 18 and had given birth to at least one child. The researchers got blood samples from subjects, and also took a look at their reproductive histories (use of contraceptives, whether they breast feed or not, etc.). Records showed that 884 women with RA and 1,949 without had breastfed at least one child.