In women with relapsing-remitting multiple sclerosis (RRMS), there is a significant increase in brain lesion volume after pregnancy, but it is not accompanied by a loss of brain cells, a study suggests.
Conducted by researchers at Harvard Medical School, the study, “Quantitative MRI analysis of cerebral lesions and atrophy in post-partum patients with multiple sclerosis,” was published in the Journal of the Neurological Sciences.
Multiple sclerosis (MS) is a chronic, inflammatory disease affecting the central nervous system. In women, it has been reported that pregnancy can slow down the progression of MS, especially in the third trimester, but the symptoms seem to reappear after childbirth.
In this study, researchers attempted to assess disease severity after childbirth in RRMS patients.
The team analyzed brain magnetic resonance imaging (MRI) data collected before pregnancy and after delivery (post-partum) from 16 women at an average age of 33 with RRMS. The post-partum MRI was performed an average of 2.2 months after childbirth, and an average of 15.4 months from the time of pre-pregnancy imaging.
They looked at both T1 and T2 images, technical terms for different MRI methods. A T1 image offers information about current disease activity by highlighting areas of active inflammation, while a T2 image provides information about disease burden or lesion load — the total amount of lesion area, both old and new.
Brain MRI results showed there was a significant increase in mean T1 lesion volume in patients post-partum (0.87 ml), compared with before pregnancy (0.55 ml). A similar significant increase was also observed in T2 lesion volume post-partum. The increase in lesion volume indicates disease progression associated with RRMS.
There was no difference observed in the number of gadolinium-containing lesions in patients before pregnancy and post-partum. Gadolinium is a dye used during an MRI to enhance the detection of inflammation and brain atrophy.
Despite the increase in lesion volume, no significant brain atrophy, or loss of brain cells, was seen in these patients, the researchers said.
“Pregnancy is associated with increased in T2 and T1 cerebral lesion load in MS. However, a de-coupling is apparent, with no whole brain or cortical atrophy developing despite the increase in destructive lesions and despite the expected pregnancy-related decline in brain volume,” they wrote.
According to the team, the study has some limitations that could have influenced its outcomes, including the lack of a control group with which to compare the results, the relatively small number of participants, and the short follow-up time. Further studies are therefore needed to validate the findings.
“While in the short term, pregnancy may be protective against the brain volume loss expected with increased lesion load, longer duration of follow-up is needed to verify these findings,” the team concluded.