Treatment for major cause of recurrent pregnancy loss

Amongst women who experience recurrent pregnancy loss, around 20% test positive for a specific antibody that targets the mother’s own body. A Kobe University-led research team now found a treatment that drastically increases these women’s chances of carrying to full-term without complications.

Recurrent pregnancy loss is a condition of women who have lost two or more pregnancies for non-obvious reasons. The Kobe University obstetrician TANIMURA Kenji and his team have previously found that in 20% of these women, they can detect a specific antibody in their blood that targets their own bodies. Tanimura explains: “There is no known treatment for this particular condition, but the antibodies have a similar target to those that play a role in a different condition that has an established treatment.” Therefore, he wanted to test whether that treatment also works in the cases with the newly discovered antibody.

Tanimura enlisted the help of obstetricians across five hospitals in Japan and over the course of two years analyzed the blood of consenting women suffering from recurrent pregnancy loss for the antibodies. If any of these women got pregnant during this time frame, their doctors would offer treatment options also containing those drugs that are effective against the chemically similar condition, specifically, low-dose aspirin or a drug called “heparin.” The research team then observed how many of the women who included these drugs in their treatment had full-term live births or pregnancy complications and compared that to the pregnancy outcomes in women who did not take either of the two drugs.

The Kobe University researchers now published their results in the journal Frontiers in Immunology. They report that women who received the treatment were much more likely to have live births (87% did) compared to the ones without treatment (of which only 50% had live births). In addition, amongst the live births, the treatment reduced the likelihood of complications from 50% to 6%. “The sample size was rather small (39 women received the treatment and 8 did not), but the results still clearly show that a treatment with low-dose aspirin or heparin is very effective in preventing pregnancy loss or complications also in women who have these newly discovered self-targeting antibodies,” summarizes Tanimura.

Many women who tested positive for the newly discovered self-targeting antibodies also tested positive for the previously known ones. However, the Kobe University-led team found that women who only had the newly discovered antibodies and who received the treatment were even more likely to have a live birth (93%) and, amongst these, none had pregnancy complications.

Looking ahead, Tanimura says: “The newly discovered self-targeting antibody has been demonstrated to be involved also in infertility and recurrent implantation failure, as well as a risk factor for arterial thrombosis in women with systemic rheumatic diseases. I therefore expect that studies about the effectivity of the treatment against a broader range of conditions might produce encouraging results.”

This research was funded by the Japan Society for the Promotion of Science (grants 24K12532, 20K09642, 23K08888, JP18H05279, 24K02691 and JP18K19450), the Japan Agency for Medical Research and Development (grants JP18gk0110018, JP21gk0110047, JP23fk0108682, JP22gn0110061, JP17fm0208004 and JP19ek0410053), the Japan Science and Technology Agency (grant JPMJMS2021), and the Ministry of Education, Culture, Sports, Science, and Technology Japan (grant JP190H04808). It was conducted in collaboration with researchers from the University of Toyama, the University of Yamanashi, the University of Tokyo, Okayama University, the Department of Public Health, Dokkyo Medical University and Osaka University.

Kobe University is a national university with roots dating back to the Kobe Commercial School founded in 1902. It is now one of Japan’s leading comprehensive research universities with nearly 16,000 students and nearly 1,700 faculty in 10 faculties and schools and 15 graduate schools. Combining the social and natural sciences to cultivate leaders with an interdisciplinary perspective, Kobe University creates knowledge and fosters innovation to address society’s challenges.