Valtrex is actually a very well studied drug. It is a prodrug for acyclovir, which has been around for 30+ years. Valtrex turns into acyclovir after it is absorbed which allows your body to get more of the drug into your system for longer (which is why you take Valtrex less frequently than acyclovir).
Although it has not been officially tested for use during pregnancy (very few drugs ever are as to do this would require testing on pregnant women … not a thing most people are happy with), it is considered safe to use when pregnant — a category “B” medication. There was at one time a pregnancy registry for acyclovir (the drug your body converts Valtrex into) that followed pregnant women. Somewhere close to 1000 women taking Valtrex while pregnant were followed and the rate of defects amongst that group was considered to be the same as for women not taking any medication. There was for a while a registry for Valtrex as well, but it ran for a shorter period of time and, although the results were similar, the number of women followed was not enough to draw as strong of conclusions.
Taking Acyclovir or Valtrex suppressively during the last weeks of pregnancy is recommended. Even though you are passing the antibodies onto your infant, the suppressive therapy should prevent you from shedding the virus and/or having an outbreak. During the last weeks of pregnancy your child is less likely to suffer any ill effects from any medication you may take. This is not to say you should not weigh your options and make your own decisions.
I took Valtrex throughout my pregnancy and my child is fine and beautiful. I was comfortable enough with the drug’s profile that I told my doctor up front that I intended to take the drug throughout my pregnancy to protect my partner.
I doubt you need to be concerned about allergic reactions, especially if you’ve taken the drug before as you would have had the reaction then. Valtrex/Acyclovir have very low allergic profiles (aka even people with a bad history of allergies normally don’t react to them). Antivirals are completely different beasts from antibiotics and just don’t wreak the havoc on your body that an antibiotic can. Valtrex/Acyclovir very specifically targets herpes by mimicking a substance the virus needs to reproduce. When the virus grabs onto the antiviral, the antiviral gets in the way of the virus being able to reproduce. The substance Valtrex/acyclovir mimics is not a substance your body needs so your body doesn’t tend to react to the drug much.
I’m trying to break down a complex bit of biochemistry here, so I may be guilty of oversimplifying how Valtrex/acyclovir works. There are some resources on the net that go into this stuff in detail and you may want to read up on them if you are interested in a more advanced explanation. – Lorraine
If you have something to say about herpes and what it’s like to be pregnant when you have herpes I’d love to hear from you. You can send me bits of advice OR your own personal story and I would be more than happy to publish it so that we can work to help people that don’t know enough about this to make a decision for themselves.
As with anything health related please see your own doctor. Our personal experiences shared do not indicate truth for everybody that is in similar situations. The information shared is based on our own personal experiences. No two herpes cases are alike.