Women with rheumatoid arthritis who undergo assisted reproduction treatment have a decreased likelihood of live births versus women without rheumatoid arthritis, according to authors of a recent Denmark-wide cohort study.

The problem might be caused by an impaired chance of embryo implantation, authors of the study reported in the Annals of the Rheumatic Diseases.

Corticosteroids prescribed before embryo transfer might have improved the likelihood of live birth in these women with rheumatoid arthritis, according to the investigators, led by Professor Bente Mertz Nørgård of the center for clinical epidemiology at the Odense (Denmark) University Hospital.

However, findings with regard to that potential effect of corticosteroids were “not unambiguous,” said Prof. Nørgård and her coauthors said in their report.

The cohort study, based on Danish registry data from 1994-2017, included 1,149 embryo transfers in women and rheumatoid arthritis with 198,941 embryo transfers in women without rheumatoid arthritis.

Live births per embryo transfer were less likely in women with rheumatoid arthritis versus those they were in women with no rheumatoid arthritis, with an adjusted odds ratio of 0.78 (95% confidence interval, 0.65-0.92), according to investigators.

Chances of biochemical and clinical pregnancies were also lower in women with rheumatoid arthritis, with odds ratios of 0.81 (95% CI, 0.68-0.95) and 0.82 (95% CI, 0.59-1.15), respectively, the investigators found in an analysis of secondary outcomes in the study.

Corticosteroids prescribed before embryo transfer increased odds of live birth, with an adjusted odds ratio of 1.32 (95% CI, 0.85-2.05), though the underlying reason why corticosteroids were prescribed could not be established in this data set, investigators cautioned.

“The impact of corticosteroid prior to embryo transfer, found in our study, could be due to a suppression of ‘abnormalities in the immune system’ in women with RA, but we have to underline that this is speculative,” Prof. Nørgård and her colleagues said in a discussion of their results.

Future investigations are needed to clarify the role of corticosteroids in women with rheumatoid arthritis undergoing assisted reproduction treatment, they added.

Support for the study came from the Research Foundation of the Region of Southern Denmark and the Free Research Foundation at Odense University Hospital. Dr. Nørgård and her coauthors said they had no competing interests related to the research.

SOURCE: Nørgård BM et al. Ann Rheum Dis. 2019 Jan 12. doi: 10.1136/annrheumdis-2018-214619.