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August 5, 2010 11:02 AM

What is the best and worst time of the month for women to donate blood?

Today was my 4th time attempting to donate blood, and my hemoglobin was too low. I've never had a problem with my iron levels the other 3 times, but today it was 11.1 (!) on the first prick, and 12.0 on the second prick. That variation seems pretty big to me, but still not high enough to donate (I've previously been in the high 12s and low 13s).

It had me puzzled why my hemoglobin is so low, because there haven't been any changes in my health or diet since other donations. However, I'm due to get my period in less than a week, so I guess that explains it.

For a woman on a 28-day cycle, what is the best and worst time to donate blood, and to guarantee being on an iron upswing? Is the best time just after your period? Is the worst time during your period, or just before it?

posted by raztaj to health & fitness (10 answers total)

The two times I donated either while on or just after my period, I barely made the iron cut and then I fainted. I think that as long as you avoid the times you are actively losing iron (or have just lost a bunch), you should be fine. There's no real reason your iron should be low before your period starts.

Iron fluctuates in the body quite a bit. I just got into a habit of eating a lot of beef and spinach etc for the few days before my scheduled donation.
posted by arcticwoman at 11:41 AM on August 5, 2010

My sister-in-law was a Red Cross RN and told me that hemoglobin levels can be affected by things as simple as the weather or stress or how much sleep you have had. When they used to take the blood sample from people's ear lobes,---what, about 7 - 8 years ago? they rarely had people test with low hemo levels. But since they changed to the finger, it is more accurate.

She said to eat iron rich foods like beans, nuts, dried fruits, meat etc. I never have a problem with my hemoglobin anymore.
posted by chocolatetiara at 11:51 AM on August 5, 2010

From what I understand about girlparts, donating right after your period would be a BAD idea. You're already bleeding out, why exacerbate the situation? I'd say the middle of the cycle wouldn't be a bad idea.

Something I have more experience with: Nthing the suggestion of eating red meat for a day or three, and making sure you get a bit of exercise each day. Eat an hour or so before you go, and bring something to eat or drink afterward; I bring a giant water bottle with me everywhere I go, and I eat a ham and cheese sammich with spinach and other accouterments.
posted by Heretical at 12:08 PM on August 5, 2010

Hmmm. I'm pretty good about eating things with iron and vitamin C - I eat loads of spinach (cooked and raw), broccoli, bell peppers, beans, chickpeas, and nuts. I only eat meat 1-2 times a week, but this hasn't been an issue during other donations. My eating habits haven't changed, and I regularly include stuff like the above nearly daily.

I figured that getting my period in the next week would be a factor, because that's generally when the endometrium thickens. The blood lining increases a lot in that week, so (I think?) hemoglobin decreases as, well, "resources" get directed for other functions. I would presume hemoglobin levels to be lowest during the week before getting your period, but I don't really know to be honest (hence this question).
posted by raztaj at 12:24 PM on August 5, 2010

I don't even try to donate blood unless it's at least a week after my period. I don't eat red meat, but I started adding canned beans to my salads, and I eat some dark chocolate every day, and I don't have any problems with low iron.
posted by mogget at 12:26 PM on August 5, 2010

I cannot donate blood before 11am. If I try first thing in the morning (even if I've eaten breakfast) my iron is too low and I usually faint. Also, my blood pressure is very low when I first wake up, the Blood Center gets nervous about sticking a needle in me!

Maybe you should try in the afternoon, after a good lunch, at least a week after your period finishes? And stay hydrated, too much coffee and not enough water was what had me fainting the last time I donated.
posted by lootie777 at 12:58 PM on August 5, 2010

donating right after your period would be a BAD idea. You're already bleeding out

You're not actually losing blood from your circulatory system during your period. After ovulation, your uterus collects a lining of (mostly) mucous and (a little) blood that's thick and red, but not really huge amounts of blood. During your period, the uterus gradually sheds all of that lining.

So during the period itself, you're not truly bleeding. You've put *some* blood into your uterus during the two weeks before, but not huge amounts, and all that red stuff that comes out later is mostly not blood.

Okay, I've expended my knowledge on the topic, but I think I vaguely recall that if you're putting enough blood into your uterine lining to cause significant changes in your blood counts, it's a problem. On the other hand, other posters are pointing out it may have nothing to do with your cycle and more to do with other factors.
posted by galadriel at 4:10 PM on August 5, 2010

careful not to confuse low iron levels with low hemoglobin and hematocrit levels aka anemia (in some of these answers). You can have a low H&H that has nothing to do with iron deficiency. Also to the OP, you listed a lot of nice veggies and so forth in the description of what you eat for iron - are you a vegetarian or vegan by chance? B12 deficiency can cause a microcytic anemia. Although I suspect you would have mentioned it if this were the case.

There is actually a pretty wide variation when testing H&H, especially by fingerstick. for hematocrit it's about a +/- 2 (i.e. a 38 could be 36-40) at least on the machines I'm used to working with.

anyway, good for you for giving blood and being so determined to give! we who need to have the blood to give away thank you kindly.
posted by treehorn+bunny at 9:15 PM on August 5, 2010

I'd never really thought about the time-of-month affecting blood donation. I've given blood in every phase of the ladycycle with no problems.

I was having huge problems for a while getting my hematocrit levels up where they needed to be -- here in Florida, they require a measurement of 38 to donate, and I was regularly hitting 35 or 36. No matter how much red meat, spinach, or whatever other recommended foods I ate, I was always just shy.

I solved the problem by not eating wheat products in the week leading up to donation. Boom, usually 39 to 41 every time, and no problems at all with any dizziness afterward.
posted by themissy at 9:16 AM on August 7, 2010

way overdue update to this! thank you for all the helpful replies!

turns out, i think i was just trying to donate too frequently. i had been donating roughly every 2 months when posting this, and my body just couldn't keep up with replenishing enough red blood cells in the 8 week time that the red cross requires between donations. but somewhere between 3-4 months, and my iron levels shoot up loads! so every 4 months, instead of 2, it is...
posted by raztaj at 1:35 PM on February 15, 2011