Are you pregnant or planning to fall pregnant?

Dobson et al. The month of birth effect in multiple sclerosis: systematic review, meta-analysis and effect of latitude.  J Neurol Neurosurg Psychiatry doi:10.1136/jnnp-2012-303934

Background:  Month of birth has previously been described as a risk factor for MS. This has been hypothesised to be related to maternal vitamin D levels during pregnancy, although conclusive evidence to support this is lacking. To date, no large studies of latitudinal variation in the month of birth effect have been performed to advance this hypothesis.

Methods: Previously published data on month of birth from 151 978 MS patients were compared to expected birth rates. A linear regression model was used to assess the relationship between latitude and observed:expected birth ratio of MS patients for each month.

Results: Analysis of all reported data demonstrated a significant excess of MS risk in those born in April (observed:expected 1.05, p=0.05) and reduction in risk in those born in October (0.95, p=0.04) and November (0.92 p=0.01). A conservative analysis of 78 488 patients revealed an excess MS risk in those born in April (1.07, p=0.002) and May (1.11, p=0.0006), and a reduced risk in those born in October (ratio 0.94, p=0.004) and November (0.88, p=0.0002). A significant relationship between latitude and observed:expected ratio was demonstrated in December, and borderline significant relationships in May and August.

Conclusions: Month of birth has a significant effect on subsequent MS risk. This is likely to be due to ultraviolet light exposure and maternal vitamin D levels, as demonstrated by the relationship between risk and latitude.

“If you are pregnant or planning to fall pregnant you need to make sure you are vitamin D replete. This may lower the chances of your child getting MS and other autoimmune diseases. My recommendation for pregnancy is 10,000U vD3 per day; this is double my recommendation of 5,000U per day for adults.”

What the press have to say:

Give pregnant women vitamin D supplements to ward off multiple

Medical Xpress
The risk of developing multiple sclerosis (MS) is highest in the month
of April, and lowest in October, indicates an analysis of the available
evidence, published online in the Journal of Neurology Neurosurgery and
Psychiatry. The findings, which
See all stories on this topic »
Vitamin D in pregnancy may prevent multiple

PARIS — Researchers said Thursday they have found evidence that Vitamin D
supplements for pregnant women in the world’s colder, darker countries may
stave off multiple sclerosis (MS) in their offspring. The finding adds
to a growing body of work
See all stories on this topic »
Other related posts of interest on this blog:

27 Aug 2012
This month of birth effect is now being attributed to the effect of low vitamin D levels in the womb. The low vitamin D affects how the immature immune system develops. In other words if your mother was pregnant during winter, 
21 Sep 2012
“The results of this study support the month-of-birth effect, but question the link to UV fluctuation. Unfortunately, this study cannot take into account cultural factors that affect UV exposure and vD, for example indoor vs. outdoor 
03 Nov 2012
Investigating the month of birth effect in second generation MSers has not yet found anything interesting, Why not take it back another generation, so on and so forth? Posted by MouseDoctor at 07:00 · Email ThisBlogThis!
14 Jun 2011
The month of birth and risk of MS are associated, more so in familial cases, implying that there is some interactions between genes and environment that may be related to climate. Such interactions may act during gestation or 

CoI: This work was done in our group.

15 thoughts on “Are you pregnant or planning to fall pregnant?”

  1. VV says too much vitamin D may actually encourage an already misbehaving immune system to misbehave even more: does that theory hold any ground? Is vitamin D in high amounts (10,000 IU per day) too dangerous to an MSer?

    1. 10,000U/day = 15-30 mins in the mid-summer sun with your upper body exposed. Regardless of its effects on immune function you need to be vD replete for your bone health. We are not talking pharmacological doses, but physiological supplementation. Since woman have started wearing make-up with sunblock, we have stopped going outdoors (facebooking/gaming generation), we don't eat wild fish and with increasing pollution levels that filter UVB light we have become more and more vD deficient. All this is advice; the good thing about choice and knowledge is that you can ignore it if you like.

    2. Prof G, I just want to know if it will exacerbate my disease. VV sounded so convincing in his assumptions that it's worried me.

    3. Not that we are aware of! There are trials looking to see if it reduced relapses. There is no data to the contrary.

    4. I don't remember VV saying this. Do you have a link or a date?He did say that low Vit D may be the result of MS rather a cause

    5. You’re correct. I have misquoted Vasilis Vasilopoulos. I apologise. He did say that MS patients are Vit.D deplete because there is a constant immune alert against the continuous damage. He did argue that multiple sclerosis is most probably the result of MS and not part of its cause. Sorry.

    6. *CORRECTION* VV said vit D depletion is most probably the result of MS and not part of its cause. Sorry again.

  2. Has there ever been any investigation into if people with MS are more likely to get pregnant in the summer months? This would result in spring birthdays of babies genetically more likely to get MS themselves, and would potentially invalidate some of the above conclusions.I don't know if this is a particularly strong hypothesis, but it seems to be an unexplored one.

Leave a Reply

%d bloggers like this: