[Question #947] Menstruation and relative risk

50 months ago

Hello There

I am based out of the UK and 6 weeks ago I had an incident that I felt uncomfortable with. I met a Russian Girl who has lived in the UK for 16 years, she had a fairly good job and seemed presentable. Anyway she told me that she was a PWID for less than a month back in Russia and altogether I just didn’t really trust her.  Due to stupidity and inebriation I ended up having unprotected vaginal sex with her whilst she was on her period. I am trying to establish the relative risk of insertive vaginal sex during menstruation and also I want to factor in that I have sebaceous cysts on the glans. In other words was this a high risk exposure (should I still be concerned) and any detail on how menstruation affects the likelihood of transmission female to male would be appreciated. The reason why I ask is that I have had a negative 30 day test on a 4th generation duo full blood screen and UK advice is only to be concerned if you was in a high risk exposure. I also recently developed a strep throat/oral thrush though that could be stress of the situation.

Many thanks in advance

H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
50 months ago
Welcome to the forum. Thanks for your question.

The bottom line is that you didn't catch HIV; the 4th generation HIV blood tests are 100% conclusive 4 weeks or more after the last exposure. So no matter now high the risk of HIV was at the time of exposure, you weren't infected and needn't worry further about it.

Having said that, the risk wasn't all that high anyway. I'm not familiar with "PWID", but I'm guessing at "person who used injection drugs" (?). Obviously unproteted sex with someone at possible high risk for HIV carries some risk. But most injection drug users, even in Russia, are not infected. Even if she was, when a woman has HIV the average transmission risk female to male is around once for ever 2,000 unprotected vaginal sex events. Sex during menstruation has little effect on transmission risk; in infected women, the concentration of HIV is similar in blood and genital fluids. At most it doubles the risk; if so, it would raise the chance of transmission to an average of 1 in a thousand exposures.

But as I said, for sure you weren't infected. Your possible strep throat do not change my assessment, and neither does oral "thrush". (I doubt you had thrush, i.e. a yeast infection. White coated tongue isn't the same thing, but is very common in upper respiratory viral or strep infections.) Anyway, no no further worries.

I hope this has been helpful. Best wishes and stay safe--  HHH, MD


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50 months ago
Sincerely many thanks Dr Handsfield. Looking at your credentials it's very reassuring and a privilege to be able to converse with you even on these forums. I hope my follow up questions do not come across as condescending or insulting.

I researched a lot of periodicals and journals on the matter of menstruation and transmission rates and couldn't really find anything substantial and up to date. Would you say your views on the relative risk of menstrual blood are fairly consensus views in the field please? out of interest how do researchers in the field make a view on this?

for future reference  are my sebaceous cysts are a liability in potential transmission? or is this more an issue when you're dealing with open sores?

also regards the 100% conclusion accuracy I appreciate your bold statement. Obviously they're extenuating circumstances that can always apply to any situation however was interested to find out as to why you are so confident in the 4th generation tests at 28 days when other groups aren't willing to commit (clinical experience?, overview of information?)

Again I really appreciate how you have answered already so please do not intimate I am challenging the responses, after many hours of fruitless searching it's brilliant to speak to a leading expert. And yes, I know promise I will stop going on the internet after this discussion is concluded as it's not obviously helping ; ) 

p.s my GP (general practitioner)  again seemed to harbour the view that a three month test is definitive and I actually pushed back that this view was outdated, the root of my question is whether or not my experience was high risk and from speaking with you I do not believe it was. 


H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
50 months ago
Thanks for the thanks. I'm glad to be helping.

There is strong consensus on menstrual blood exposure as carrying little increase HIV risk. You're having trouble finding specific data because there have been few formal research studies -- and the reason for that is the consensus itself, i.e. such research really not worth the effort or expense.

Sebaceous cysts are not likely to increase the risk of catching HIV, but I'm unaware of any specific research on it. In general, no penile skin problems have been shown to significantly increase risk when sexually exposed, except for genital herpes, syphilis, or chancroid (a rare STD).

As we have said many times on this forum, official agencies typically take conservative positions on test performance, and are often required by their legal departments to toe the line of test manufacturers' advice. However, Dr. Hook and I have the flexibility to interpret the available research and clinical experience, which indicate that nobody has ever been documented to in fact have HIV after a negative 4th generation HIV test at 4+ weeks. Your GP is definitely behind the times:  the 3 month window applied to the earlier generation HIV tests, i.e. the first and second generation HIV antibody-only tests. But habit plus official recommendations are the only reason to continue to follow that standard.

On top of which your exposure was pretty low risk anyway. Chance a partner like yours has HIV, let's say 1% (1 in a hundred) (actually it's probably a lot lower); average transmission risk for each episode of unprotected vaginal sex is around 1 in 1,000 (actually 1 in 2,000, but let's not quibble). Thus the chance you caught HIV calculates as roughly 1 in 100,000. And if you then assume your test result is "only" 99% accurate. If so, the chance you have HIV in the face of that result is 1 in 10 million. That's equivalent to zero by any rational analysis. (By contrast, according to the National Safety Council, your chance of dying in a traumatic accident -- traffic, drowning, falling, etc -- is 1 in 1,756 every year. In other words, thousands of times higher than the chance you have HIV.

So my advice is to move on without further worry. And don't forget your seat belt!
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50 months ago
Many thanks Dr Handsfield and yes I will buckle up.

I think you and the rest of the experts provide a sterling service and yes it was unfortunate my GP lacks awareness, to be fair I may make a formal complaint based on other reasons.

May I ask, why do you do this? it appears to be purely charitable on your part?

Also I am aware I am out of responses so once again thanks for your help

best regards
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
50 months ago
For sure don't lodge any sort of complaint against your GP in regard to these issues. It sounds like he has given you standard advice, nothing to complain about. Certainly you cannot fault someone for giving official advice.

The moderators' motivations aren't so mysteriaous. We get a portion of each posting fee as modest reimbursement, but we do it primarily because we feel strongly about STD/HIV prevention, understand that truly expert advice can be hard to find, and we enjoy helping people by providing it.

Thanks for the kind words. Take care.

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