Question about CMV
Do any of you have any experience with testing for CMV in pre-natal blood test? I had a flu-like fever in my first trimester, got over it just fine, and now at 33 weeks, they want to send me for a blood test to test for CMV. The nurse seemed to indicate it was routine for anyone with a fever in early pregnancy.
What I want to know is, what will the blood test show? Can it show whether or not my baby was infected with CMV? How will the information effect my birth options?
If you have any info or advice, I would so appreciate it!
I have no idea, but a preg.org friend of mine might. I let her know you were asking about CMV and hopefully she'll either post here soon or get back to me about it. She just had CMV (not pregnant) and is also a scientist so I'm guessing has plenty of info on CMV in general.
Hi Ayelet. I was diagnosed with a primary CMV infection back in February and I also happen to know a lot about it because I have friends at my University who study it. I had just had my IUD removed so it affected our TTC plans. Affected them in that I've had to wait to TTC until just this month. I went through a huge ordeal getting the correct diagnosis but in the process I learned a ton about testing for CMV.
A little about the virus: CMV, Cytomegalovirus, is a herpes simplex virus. Like the herpes viruses that cause genital & oral herpes, chicken pox, and mono (epstein barr virus), CMV stays in your system for life once you've contracted it. Most people get CMV when they're little and don't even know it because it presents like a lot of other annoying little viruses in toddlers. About 90% of Americans have had CMV at some point in their lives. Percentages might be a little different in Israel but that matters little for you if you grew up in the US. Like the other herpes viruses, CMV can reactivate. CMV reactivates all the time, according to the researchers I know, but doesn't cause symptoms very frequently when it does. If you get CMV for the first time (a primary infection) when you're older, it causes mono-like symptoms (I have my own theory as to why it does that but that's another story :) ).
CMV is only problematic if you're immune-compromised or pregnant. Its ONLY a problem when you're pregnant if its a primary infection that you get while you're pregnant or if you have a primary infection in the months preceding pregnancy (literature is sparse on this topic). If you have a primary CMV infection while you're pregnancy, you have about a 50% chance of infecting the fetus. Rates are lower in the months preceding pregnancy. Of those fetuses infected, something like 5-10% are symptomatic. Symptoms can be mild to very severe. I won't go into a lot of detail because its not my job to scare you. The internet has probably already done a good job of that.
Any test they give you now isn't likely to tell you a whole lot. There are several tests they can run. You could have a test done that determines if the virus is currently present in your blood. This would tell you if you have an ACTIVE infection. Given that you had a fever several months, this test would most likely be negative even if the fever was due to CMV. They could run a test to check for CMV antibodies (the molecules in your immune system that recognize specific viruses, bacteria, etc.). There are two types of antibodies they'll be looking for, IgG & IgM. If you have CMV IgG antibodies present, it means you've have CMV at some point in your life. It could have been 3 months ago, 3 years ago, or 30 years ago. Presence of the other antibody, IgM, indicates the infection is more recent but doesn't necessarily mean the infection was primary (first time you've ever had it). To determine if the infection was primary, you'd need to have an antibody avidity test done, which looks at the IgG and more or less assesses their "maturity". Mature IgG indicate a past infection but past could mean 3 months ago, 3 years ago, or 30 years ago. If this were really a concern of theirs, they should have tested you when you had the fever because there's virtually no way to tell NOW when you had CMV if you've ever had it. Does that make sense?
I'm not an MD but I can say from experience that just having a fever in pregnancy is not a good indicator that you had a primary CMV infection. Are you in Israel now? Some countries do implement routine CMV testing during pregnancy (the US doesn't) and as a routine well-woman test. The test would be useful now if you've also had the test prior to getting pregnant. For example, if you were previously negative for CMV IgG and now you're positive, there's a good chance it was a primary CMV infection. Conversely, if you've ever tested positive for CMV in the past then you're in the clear now. Ah, and a quick google search tells me Israel is one of those countries that does test routinely Screening for Cytomegalovirus during Pregnancy.
As for how this will affect your birth, its hard to say. What are your birth plans? If your doctor is satisfied that you didn't have a primary CMV infection then it shouldn't affect your birth at all. If there's a chance that you might birth a CMV-infected child then you might not want to have a home birth as the child may need immediate medical care. Your doctor can tell you more about how they proceed, especially since the testing is routine if you're in Israel.
Hope that helps!
Mel, let me know if she has additional questions since I don't check in very much (at all) any more. :)
Thanks Mel, and Erin. That was very comprehensive! Thank you! "Routine" in Israel, at least for pregnancy is very dependent on the dr you see. It's one of the few ways that stereotyping actually works to my benefit! When they see the head covering and modest clothes and they know I'm religious, they assume that I'm going to refuse most of the tests. Many ultra-orthodox will consult their rabbi before having any pre-natal testing done, including ultrasounds! So even though I'm not one of those people, my dr automatically asked me on the first visit which tests I usually do, and I told her just the organ scan and a blood test at the beginning. I took that test after the fever too, so if they did routinely check, they would have known then!
I am fairly certain that I don't have an active infection and that the virus I had way back was the standard flu that was going around. And I am planning a home birth. I don't think anyone is going to do any extra testing if I have antibodies to find out how mature they are. I am sure I would have to fight for that and I might even have to pay for it privately. I would be worried that if there was any indication that I might have been infected in this pregnancy, that I would be placed out of a home birth without any further testing. I have a friend who's baby was infected w/ CMV and has hearing problems, so I know the risks.
But I guess I'm still wondering, if the risk is so small, would I actually have to give birth in a hospital? What are the situations that would require immediate care? And are there ways to know in advance how likely it is that my baby is effected? Would anything have been seen on the organ scan? He was pretty thorough!
Mel, can you pass this on to Erin? Thanks so much!
The risk isn't all that small to infected women. Its a risk of 2.5%-5% that the child will be affected. That's MUCH higher than the risk of Downs Syndrome to a women aged 30 or less, to give you perspective. CMV is the leading viral cause of birth defects. I imagine they could see certain abnormalities caused by CMV on an anatomy scan but the virus can cause such a wide array of symptoms. Intrauterine Growth Restriction is one possible effect of CMV. That would become evident in the third trimester. I suppose the decision to birth in the hospital or not would be one that you'd have to make with your doctor. I'm not very familiar with what conditions would risk you out of a home birth and which conditions would require immediate are. I'm also not sure if there's any way to test the fetus before the birth and if there is I think it would be invasive (requiring an amnio at least).
The reason they don't test routinely in the US is that its so hard to figure out when the mother had CMV and there's really nothing you can do once you determine the mother has a primary infection. Testing can lead to unnecessary worry, as it likely is in your case.
right, which is why I am inclined not to bother testing for it when it seems that there is very little that can be determined from the blood test. I looked at the referral form and it says that they want to test for IgG and IgM as you mentioned.... But again, if I don't have any previous tests indicated that I didn't have antibodies before, then the outcome of the test can only cause one of 2 things, either I test completely negative and hurray, or I test positive and I'm suddenly higher risk. I'm not sure... I don't really have a doctor or a mw that I can discuss this with, b/c that's just not how the system works here. So I'm a little stuck without professional advice... I'll see if there's someone who I can consult with here...
Originally Posted by TiggersMommy
Thanks again so much for taking the time to answer me so thoroughly! I appreciate it!