New research suggests that more than half of women with the autoimmune diseases rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE, or lupus) have fewer children than they had desired.

According to a study published Thursday in the journal Arthritis Care & Research (a journal of the American College of Rheumatology), it appears that some women diagnosed with RA or lupus during their childbearing years consciously choose not to have children after they’ve been diagnosed. Those choices may be based on concerns that they may pass their disease on to a child, that the medication they take to manage their condition may harm a child, or that their condition might render them unable to properly care for a child.

Beyond those understandable concerns, the study found that women with RA who had had fewer children than they had once planned had experienced higher rates of infertility and those with lupus who’d had fewer children than planned had higher rates of miscarriage than women who had the number of children they had originally planned.

Researchers surveyed 578 women with RA and 114 with lupus and categorized them according to their desire to have children (or more children) at the time they were diagnosed. More than 60 percent reported they were no longer interested in having children at that time. Of those who were interested in having children, 55 percent with RA and 64 percent with lupus had fewer children than originally planned.

The authors note that concerns over medication, genetic transmission, and and inability to care for a child can be managed through patient education and treatment management; for instance, they point out that the likelihood of a woman’s passing these conditions to offspring is actually quite small.

“Beyond patient choice, however,” they write, “infertility in women with RA and pregnancy loss in women with SLE resulted in fewer children. To help women fulfill their childbearing goals, therefore, we must address patient education, as well as the underlying causes of infertility and pregnancy loss.”

According to the American College of Rheumatology, as many as 322,000 adults in the United States have systemic lupus (in which the body’s immune system attacks healthy cells, tissues or organs) and about 1.3 million have RA (which causes painful joint inflammation). Both conditions are more common among women than men and often are diagnosed during childbearing years.