Reproductive history of the Danish multiple sclerosis population: A register-based study

Background: A diagnosis of multiple sclerosis (MS) may impact the choice of parenthood. Objective: To investigate the number of live births, abortions and ectopic pregnancies among persons with MS. Methods: From the Danish Multiple Sclerosis Registry, we extracted data from all persons diagnosed with MS from 1960 to 1996 and matched each MS person with four reference persons. We used a negative binomial regression model for the live births and Poisson regression model for abortions and ectopic pregnancies. The total fertility rate (TFR) during 1960-2016 and the annual number of live births in the MS population were analysed. Results: Persons with MS had fewer children than reference persons. Fewer women with MS had elective abortions after diagnosis (incidence rate ratio (IRR) = 0.88; 95% confidence interval (CI) = 0.78-1.00) than reference persons. There was no difference regarding the number of elective abortions, spontaneous abortions or ectopic pregnancies after onset. The TFR was lower for women with MS than for reference persons, and the number of annual live births by MS persons increased during 1960-2016. Conclusion: MS seems to considerably impact reproductive choices, especially after clinical diagnosis, resulting in the MS population having fewer children than the general population.