The findings suggest that concerns related to pregnancy may result in delayed or reduced use of disease-modifying treatments (DMTs), even before pregnancy is considered.

The study also found that the difference in treatment became apparent after two years of disease duration for DMTs and as early as one year for HEDMTs. Notably, this gender-based treatment gap did not significantly change with patient age, suggesting that therapeutic inertia could persist regardless of the woman’s stage in life.

“These findings emphasize the crucial need to reconsider how we make treatment decisions for women with MS, especially those of childbearing age,” says Professor Sandra Vukusic, the lead author of the study. “Women may not be receiving the most effective therapies at the optimal time, often due to concerns about pregnancy risks that may never materialize. The use of Disease-Modifying Therapies (DMTs) and Highly Effective Disease-Modifying Therapies (HEDMTs) is frequently limited by potential and unknown risks associated with pregnancy, as there is often insufficient data available when these drugs first come to market.”

Both neurologists and patients contribute to therapeutic inertia, with many adopting a cautious approach and avoiding these treatments. “Neurologists may be reluctant to prescribe DMTs, especially if they are not comfortable managing pregnancy-related issues,” explains Professor Vukusic. “At the same time, women understandably do not want to take any risks for their child or pregnancy. Their primary concerns are congenital malformations, fetal loss, and fetal growth disorders. Women will also feel uncomfortable if their neurologist appears uncertain.”

Moving forward, the research team plans to further investigate the factors contributing to therapeutic inertia. They aim to improve treatment strategies prioritizing the long-term health of women with MS and their reproductive goals.

“The main impact of this inertia is the less effective control of disease activity during DMT-free periods, leading to the accumulation of lesions and an increased risk of long-term disability,” emphasizes Professor Vukusic. “This represents a real loss of opportunity for women, especially in an era where DMTs are so effective when used early.”