Multiple sclerosis linked to higher risk of mental illness during and after pregnancy

People with multiple sclerosis (MS) face a significantly higher risk of perinatal mental illness compared to those with other chronic conditions, according to a new study analyzing over 890,000 births in Ontario.

The research, published online in Neurology, sheds light on the mental health challenges faced by people with MS during pregnancy and the first year after childbirth.

Using population-based health data from ICES, the study found that 8% of people with MS experienced a new mental illness during pregnancy, rising to 14% in the first year postpartum. Depression and anxiety were the most common conditions reported.

The study compared mental health outcomes among those assigned female at birth with MS (close to 1,700) to females with epilepsy, inflammatory bowel disease, diabetes, and people without these chronic conditions. The researchers analyzed mental illness before conception, during pregnancy, and up to three years after giving birth.

The first year after childbirth was found to be a particularly vulnerable period, with people with MS being 33% more likely to experience a mental illness than people without MS or another of the studied chronic diseases. Overall, half of people with MS were living with a mental illness in the first year postpartum.

“Our findings highlight the heightened vulnerability of mothers with MS to mental illness, emphasizing the need for mental health screening and early intervention, including the use of preventive strategies,” says lead author Dr. Ruth Ann Marrie, a Professor of Medicine and Multiple Sclerosis Clinical Research Chair at Dalhousie University.

Key findings:

People with MS had a 26% higher incidence of mental illness during pregnancy and a 33% higher risk in the first year postpartum compared to pregnant people without MS, after adjusting for factors such as age, socioeconomic status, and obstetric complications.
Mental illness affected 42% of people with MS during pregnancy and 50% in the first year after giving birth, compared to 30% of people without MS during pregnancy and 38% in the first year after birth.
About 1% of people with MS experienced psychosis and nearly 6% developed substance use disorders within one year of giving birth.
People with epilepsy, inflammatory bowel disease and diabetes also had increased risks of mental illness during pregnancy and in the first postpartum year compared to people without these conditions.

While people with MS consistently showed elevated risk, the findings suggest a broader need for mental health support across chronic conditions during the pregnancy and postpartum period.

One limitation of the study is that administrative data can only capture mental health issues for which health care services are sought, which means that the burden of mental illness among this population could be underestimated.

“Future studies should assess how the activity and severity of chronic diseases such as MS may affect mental health during the pregnancy and postpartum period, and how comprehensive care strategies can best support mental health during this period,” says senior author Dr. Colleen Maxwell, a Senior Adjunct Scientist at ICES and a Professor in the Schools of Pharmacy and Public Health Sciences at the University of Waterloo.