Does CCSVI explain why Pregnant Women Have Fewer Relapses
Just a thought - does anyone think this might be relevant to CCSVI?
It seems to me that the MS relapse rate in pregnant women correlates with the changes in their volume of blood and cardiac output over the course of their pregnancy. But I don't think there is a study directly linking the two. Is this another oddity of MS which seems to confirm/support the importance of oxygenated blood (and CCSVI) in MS generally?
Any scientists out there got any thoughts?
Pregnant women have fewer relapses as their pregnancy advances. The relapse rate increases in the three months following delivery and then returns to pre pregnancy rate.
In pregnant women the volume of blood and cardiac output both increase as their pregnancy advances but returns to pre pregnancy rate about six weeks after delivery.
Rate of Pregnancy-Related Relapse in Multiple Sclerosis
In women with multiple sclerosis, the rate of relapse declines during pregnancy, especially in the third trimester, and increases during the first three months post partum before returning to the prepregnancy rate.
(See the graph within the link)
Physical Changes During Pregnancy
Heart and Blood Flow: During pregnancy, the woman's heart must work harder
because as the fetus grows, the heart must pump more blood to the uterus. By the end of pregnancy, the uterus is receiving one fifth of the woman's prepregnancy blood supply. During pregnancy, the amount of blood pumped by the heart (cardiac output) increases by 30 to 50%.
As cardiac output increases, the heart rate at rest speeds up from a normal prepregnancy rate of about 70 beats per minute to 80 or 90 beats per minute. During exercise, cardiac output and heart rate increase more when a woman is pregnant than when she is not. During labor, cardiac output increases by an additional 10%. After delivery, cardiac output decreases rapidly at first
, then more slowly. It returns to the prepregnancy level about 6 weeks after delivery.
The volume of blood increases by 50% during pregnancy
. The amount of fluid in the blood increases more than the number of red blood cells (which carry oxygen)
. Thus, even though there are more red blood cells
, blood tests indicate mild anemia, which is normal. For reasons not clearly understood, the number of white blood cells (which fight infection) increases slightly during pregnancy and markedly during labor and the first few days after delivery.
The following is an extract from the UK MS Society notes on pregnancy and MS:
"Does pregnancy affect MS relapses?
There have been many research studies examining the impact of pregnancy on MS. They all show that pregnancy appears to have a positive protective influence, with relapse rates going down, especially during the third trimester (that is between six and nine months). The reasons for this are not fully understood, but it is thought that hormone levels play a role. Improvements during pregnancy may also relate to the fact that immune system activity is lowered in pregnant women to stop them from rejecting the baby. Similar effects are seen in women with other autoimmune conditions.
However, in the first three months after the baby is born, the risk of relapse rises. This is thought to occur as hormones return to pre-pregnancy levels. Research suggests that these post-pregnancy relapses do not increase long-term levels of disability. In other words, pregnancy has no effect on the progression of MS in the long-term, rather the overall effect is neutral."
I have a hunch that it is the existence of CCSVI in pregnant women with MS which explains why the improved oxygen levels, and increased cardiac output, associated with pregnancy reduces their relapse rate - rather than just hormones and autoimmune reactions! Or is the corresponding increase in relapses, when oxygen levels and cardiac output return to normal after the birth, a complete coincidence? Maybe the brains of pregnant MS ladies get a boost at the same time as their uterus..
Is it possible pregnant ladies with MS are another exception which help to 'prove' the importance of CCSVI in MS generally?