For anti-SSA/Ro-positive mothers with a previous pregnancy complicated by congenital heart block (CHB), hydroxychloroquine may reduce the recurrence of CHB, according to a study published in the July 21 issue of the Journal of the American College of Cardiology.
Peter Izmirly, M.D., from the New York University School of Medicine in New York City, and colleagues recruited anti-SSA/Ro-positive mothers with a previous pregnancy complicated by CHB for a two-stage clinical trial (19 first stage and 35 second stage). Patients received 400 mg daily of hydroxychloroquine from before completion of gestational week 10 through pregnancy.
The researchers found that four of 54 pregnancies (7.4 percent) resulted in a primary outcome of second-degree or third-degree CHB any time during pregnancy in the intention-to-treat analysis. This was lower than the historical rate of recurrence of CHB of 18 percent. Nine mothers took potentially confounding medications after enrollment but before the primary outcome and were therefore replaced with nine additional mothers who were recruited and followed an identical protocol. In the per-protocol analysis, four of 54 fetuses (7.4 percent) developed a primary outcome. Secondary outcomes included one case of mild endocardial fibroelastosis and four cases of cutaneous neonatal lupus.
“Testing for anti-SSA/Ro antibodies is not part of the normal screening of pregnant women, but it should now be considered,” a coauthor said in a statement. “One implication of our findings is that hydroxychloroquine could be effective in preventing CHB in newborns of first-time, pregnant women with anti-SSA/Ro antibodies, which could change the way we evaluate all pregnancies regardless of a mother’s health.”