Rheumatoid arthritis is a disease characterized by persistent inflammation of the joints. Joint pain, swelling and limited function of the affected joints are the most common symptoms. If left untreated, the joints can even become permanently deformed and cartilage and bone can be destroyed. Although rheumatoid arthritis can be stressful for everyone affected, this disease poses a particular challenge during pregnancy.
Genetic Markers Help Determine Whether Rheumatoid Arthritis Worsens or Improves During Pregnancy
When women with rheumatoid arthritis (RA) plan to become pregnant, many wonder whether they should stop taking their medications and risk the disease coming back, or continue taking the medications and risk possible harm to the baby have to fear. In around 50 to 75% of all women, the disease improves naturally during pregnancy for unknown reasons, while others may experience a worsening of rheumatoid arthritis.
Northwestern Medicine scientists have identified for the first time pre-pregnancy genetic markers that could predict which women will show improvement and which pregnancy will worsen the disease. The study was published in Arthritis Research & Therapy. RA is considered an incurable disease that affects 1% of the world’s adult population and is three times more common in women.
If women with rheumatoid arthritis could know in advance whether their disease is likely to go away during pregnancy, they would also know they can stop taking their medications. Some RA medications are extremely harmful and have negative effects on the fetus, while others are considered safe. However, many women want to be on the safe side and not take any medicines during pregnancy so as not to endanger their baby. The ability to predict whether the disease will flare up or regress during pregnancy can help women plan their pregnancy and also help focus treatment during pregnancy only on those women predicted to worsen. In addition, women who are expected to improve and their baby are not unnecessarily exposed to medication.
Various Genes Expressed in the Blood Provide Information About the Disease
The researchers found that before pregnancy, a group of white blood cells called neutrophils were high in those women whose condition improved during pregnancy, and that some genes related to B cells in women whose condition worsened, were strongly pronounced. This area is not well researched, in part because it is difficult to find women for a pregnancy study before they become pregnant.
However, the researchers were able to conduct the study because they had previously established a unique pregnancy cohort in Denmark that included women with RA and healthy women before pregnancy. These were monitored over time to determine which women’s disease improved during pregnancy and which women’s disease worsened. Using blood samples taken from these women before pregnancy, the researchers examined the levels of various genes expressed in the blood. Pre-pregnancy blood samples were collected from 19 women with RA and 13 healthy women included in the prospective pregnancy cohort. Next, the researchers plan to conduct a study with a larger cohort of women to validate these results and explore why RA improves during pregnancy. If it is clear how pregnancy causes natural improvement, this can be used as a model that is safer and could improve the lives of the women and men who live with it.