Tests for infectious diseases, in general, are incomplete. Even if the antibodies to that particular virus were not high enough that the doctors think of it as a cause, it is possible that there was another infection that didn't show up on the tests, because the particular strain wasn't tested for, or because the test wasn't sufficiently accurate. Some infectious diseases are difficult to test for.

So I wouldn't rule that explanation out.

One thing you could do is do more wide ranging tests for infectious diseases by testing for their antibodies, and also you could test for cytokines (eg. interleukins) which are markers of inflammation in the body. If some of the cytokines are high then that would be an indication of an undiagnosed infection, or another cause of inflammation. Then you could look into it more, and potentially treat the infection before starting to seek another pregnancy.

Garth Nicholson, a professor and a founder of an institute has recommendations for which labs have good tests: http://www.immed.org/clinical%20testing/ClinicalTesting2015.pdf

As of 2015, he is recommending

Clongen Laboratories http://www.clongen.com

Igenex http://www.igenex.com

for infectious diseases.

He used to recommend RedLab for cytokines, but they went out of business. I'm not sure who is doing high quality cytokine testing these days. And there aren't very many people around who would be helpful in interpreting the results, since cytokines are relatively new as biomarkers. But cytokine testing can indicate problems that other tests miss.

Nicholson's perspective on chronic diseases is not shared by many doctors, so you'd have to evaluate his ideas for yourself, but I have respect for him. He has a PhD in Biochemistry, and has published hundreds of scientific papers.

An infection may not have been the cause of the problem at all, but if you want to explore it more, that's what I would suggest.

It may be worthwhile to cast a wider net in order to glean more professional opinions and sources of data while reducing any emotional response. Consider spending a useful amount of time exploring mailing lists, forums, and professional bodies. Google indicates there are tons of professional bodies in both the US and overseas that will have members who have dealt with similar experience and questions before. Some have membership requirements which a determined person can get around without too many problems, PM me if you get stuck. You may also consider asking a similar question on the various 'Ask a question' websites, but obviously the responses to a shotgun approach will vary wildly.

In doing so, you may be able to filter for more considered reactions if you phrase it as a hypothetical exam question or another form that encourages people to provide clear reasoning behind their answers. Focusing on the 'undetermined' section may lead to suggestions of non-obvious tests or papers that are obscure enough to have not appeared in initial searches.

Editing this page with useful summaries of more detailed information gleaned may boost its search ranking in the future. If it does, you may want to provide an easy way for someone to contact you without creating a LW account in case of the useful but lazy passerby.

If you have boldness, why not contact the writers of the textbook and ask them?

Have you considered family history? It was not mentioned above is all.

My sympathies to you.

This is a pretty common situation in medicine - you have a problem and you have little idea what the numbers are and insight is very hard to come by. It is incredibly frustrating. There may be studies but they only report the risks for a small number of factors or even just one (eg risk of stillbirth by age of mother or given a prior stillbirth). The raw numbers from studies are usually not available to "lay people" to allow them to do their own analysis for their own circumstances which would provide a much better insight.

When you go and look at the studies you see results that differ by a factor of 5 or worse. Does low Testosterone halve (one study), or triple (another study) your chance of getting prostate cancer? Is the risk of death within 15 years from prostate cancer at stage T1C with Gleason score 6 without surgery or radiotherapy 3% (one study) or 20% (another)? What is the incidence of impotence after prostate removal (pick a number, any number between 20% and 80%)?

You are asking "what is the likely cause?" however it is fairly likely you will never know this. Most stillbirths are never explained. There are probably thousands of things it could have been. Human reproduction is a fallible process with many points of failure. I suggest you may have to move past this question at some point.

I guess what you really need to know is "what is the risk of another stillbirth given you have had one already?".

The base rate is about 1/160 to 1/200 births. I see nothing in your report that indicates an elevated risk. I assume you have looked at the risk factors including possible family history, and found nothing.

Acording to this meta-analysis http://www.bmj.com/content/350/bmj.h3080 the chance of a second stillbirth given a history of stilbirth is about 2.5% or 1/40. This is a lot higher than the base of ~1/200 but it is still pretty unlikely.

Sorry that's the best I can offer.

I have no medical qualifications but due to various health issues I have been reading medical books and papers and learning statistics for several decades.

My sympathies for your loss.

In the tradition of "making up numbers and doing Fermi estimation is better than making up answers," I would focus on the history. The frequency of past outcomes is always a good place to start (I think that's in the Sequences somewhere) since there's no need to consider causality, only frequency and genetic distance. An example:

Simplify and assume the cause is genetic (which will overestimate the probability; environmental or shared genetic-environmental has more randomness and will have occurrence closer to the population average). What is the total number of siblings for yourself and your spouse, including both of you, and how many stillbirths were there? Add your children to the number, including the one stillbirth, and weight those double because they're the generation you want to know about. Calculate the percentage, then increase it by 5-10% as a crude correction for the assumption of a genetic cause. This is my estimate before you start thinking about causality.

Other things: If V is your son from a different relationship, his genetic distance is further so I would give him normal weight instead of double, but if L has other children I would still double them since the mother's genetics are probably more important. Optionally add any of your siblings' children, but weight them by half due to greater genetic distance. Check what percentage of stillbirths are genetic vs environmental, which could be used that to make a better correction than 5-10%. To avoid the multiple comparisons problem, make these choices before doing the analysis and commit not to change them.

Disclaimers: I am not a doctor or genetic counselor, and this is not medical advice. This is a superficial analysis written at 5am with the first few ideas I thought of, based on my unreliable intuitions about what sort of estimates might work. This sort of estimate is a lot weaker than direct evidence like the BMJ meta-analysis. I take no responsibility for any decisions that anyone makes...etc.

PS: you should probably assume the disclaimers apply to anything you read here. Also, I think another reason doctors avoid giving probabilities is that there can be legal consequences, especially if they're misinterpreted.

Thank you.