A study published in the journal, Arthritis & Rheumatology, by researchers from Denmark and the United States revealed that pregnant women in Denmark diagnosed with rheumatoid arthritis (RA) or preclinical RA are more prone to preterm delivery. The study is entitled, “Fetal Growth and Preterm Birth in Children Exposed to Maternal or Paternal Rheumatoid Arthritis: A Nationwide Cohort Study.”
RA is an autoimmune disease that leads to chronic inflammation of the joints and other parts of the body. It is estimated that around one percent of the world’s population has RA. In the U.S., about 1.5 million people are estimated to suffer from this disease, with women having a significantly higher susceptibility. Several pregnancy complications, like premature birth and low birth weight neonates, have been associated with mothers suffering from rheumatic diseases during pregnancy.
In order to determine the impact of maternal RA (women diagnosed with the disease before giving birth) or preclinical RA (women diagnosed after giving birth) on pregnancy and the newborn, a nationwide cohort study was developed. Single infants born between 1977 and 2008 in Denmark were considered, resulting in a total of 1,917,723 children. The researchers found that of these children, 13,566 had been exposed to maternal RA or preclinical RA. Newborns from mothers with RA (2,101) did not differ significantly in terms of measurements like length, head and abdominal circumference at birth, compared to babies of healthy mothers. Birth weight was found to be only 87 grams lower, and the placenta weight only 14 grams lower in children exposed to RA. Similar results were also found in newborns exposed to maternal preclinical RA (11,455).
The team found that the risk for preterm birth was, however, higher in infants whose mother had RA (odd ratio 1.48) or preclinical RA (odd ratio 1.32). “Obstetricians should be aware of the increased risk of preterm birth in women with RA and among those with preclinical signs of the disease,” recommended Dr. Ane Rom, the first author of the study, in a news release. “For women with RA, we found only a small reduction in fetal growth in their babies, which has little impact on the children immediately following birth. The long term health effects for children born to mothers with RA need further investigation.” As for paternal RA, no association was found with fetal growth or risk of premature birth.