Children born to mothers with rheumatoid arthritis (RA) appear to have an increased risk of RA and two other chronic health problems, according to a study published online recently in Arthritis Care & Research, although the number of children affected is still small. The findings are based on data for all children born in Denmark over a nearly 25-year period.
Lead author Line Jolving, a PhD candidate at the University of Southern Denmark, and colleagues undertook the study because the majority of people with RA are women, including many of child-bearing age. Yet not much is known about the effect on their children’s long-term health. Autoimmune diseases like RA have a genetic component and some past studies suggest maternal RA might lead to premature births and even birth defects, but specific long-term health effects aren’t clear.
Jolving’s team analyzed data on 2,106 children born between 1989 and 2013 to mothers with RA. Nearly 1.4 million children born during that same time period to healthy women were used for comparison.
Among the general study findings, the researchers learned that more babies of women with RA were born by cesarean section than those whose mothers did not have RA (28 percent vs. 15 percent), and more babies of moms with RA were premature (10 percent vs. 6 percent) or small for their gestational age (5 percent vs. 3 percent). Additionally, women with RA were generally older than their counterparts who didn’t have RA. The authors speculate that women with RA may have a harder time getting pregnant or wait until their disease is under control before trying to have a baby.
After birth, children in the study were followed for an average of eight years, and some for nearly 26 years. During that time, the researchers looked for 15 chronic diseases known to occur in children, including diabetes, lung disease (including asthma) and mental health problems such as schizophrenia and anxiety.
They did find higher rates of three conditions, though. Children born to mothers with RA had nearly triple the risk of developing RA, a doubled risk of thyroid disease and a 61 percent increased risk of epilepsy. The researchers say their findings are similar to those of other, differently designed studies, giving more credence to their results.
It’s not entirely clear why children develop these conditions. The researchers surmise that genes that increase susceptibility to RA may increase the risk of other autoimmune diseases, or exposure to RA in the womb (the intrauterine environment) may cause later health problems. It’s also possible that RA medications played a role, but the researchers didn’t take into account medications, lifestyle or social and economic factors that can affect children’s health.
They say their findings need to be replicated in other studies in other countries, but for now, the researchers suggest pediatricians, primary care physicians and rheumatologists should be alert to the possibility of these and other health problems in children whose mothers have RA.
Theodore Fields, MD, an attending rheumatologist at Hospital for Special Surgery in New York City, says that RA, like many diseases, appears to be caused by a combination of genetic and environmental factors and that the study bears this out.
“We have long known that there is a significant genetic element to rheumatoid arthritis, and the finding of more rheumatoid arthritis in the children of women with RA in this large Danish study isn’t surprising. Likewise, the incidence of thyroid disease is known to be higher in people with other autoimmune diseases, such as RA, so it’s not surprising children of women with RA have more thyroid disease. This article reinforces the importance of follow-up in children of women with RA,” he says.
Eliza Chakravarty, MD, a specialist in reproductive rheumatology at the Oklahoma Medical Research Foundation in Oklahoma City, says it’s important to look at the actual rate of childhood diagnoses, not just the relative risks in these kinds of studies.
“It looks very concerning that the increased relative risk of a child developing RA is nearly three times higher among RA moms compared to moms without RA, [but] the actual numbers of children who develop RA are very, very low in both groups: 2 in 10,000 with RA moms compared to 1 in 10,000 in moms without RA,” she explains. “This is true for all of the diseases they looked at in the study.”
Still, Dr. Chakravarty says these studies are important because they help doctors better understand how maternal RA and other chronic diseases affect kids.
“Ideally, any risk factors that may be identified are ones that we could intervene in,” she says, such as smoking or better disease control during pregnancy. But she adds that there’s not enough data now to change how doctors counsel women with RA regarding pregnancy, except to tell them that very few children are affected overall.
Author: Linda Rath