Yes, taking antiviral medicines such as valacyclovir (Valtrex) during pregnancy is safe and does not appear to cause birth defects in the majority of patients.
Valtrex while pregnant
If you are a carrier of the herpes simplex virus type 1 (HSV 1) or type 2 (HSV 2) and you are pregnant, your doctor may prescribe an antiviral medication such as valacyclovir to prevent the infection spreading to the unborn child.
There are several risks associated with genital herpes during pregnancy. Genital herpes is a sexually transmitted disease caused by HSV 1 and HSV 2. Although it is not associated with miscarriages, the virus can be passed on to the baby during pregnancy and cause neonatal herpes.
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Neonatal herpes is a serious condition that can affect the brain and organs and in the worst case be fatal. If only a newborn’s skin and eyes are affected, the disease is more easily manageable.
Women who are carriers of HSV before the start of their pregnancy have a 1% chance that the infection is spread to the baby during birth. But late infections during the last trimester are much more serious and carry a 50% risk of the baby contracting HSV.
To lower the number of herpes breakouts during pregnancy, doctors can prescribe valacyclovir and acyclovir.
What is valacyclovir?
Valacyclovir is an antiviral prescription drug that can be used to treat herpes outbreaks during pregnancy. In addition, herpes suppressive therapy is commonly recommended for women who carry HSV. This ensures that babies are not infected during delivery.
How does valacyclovir work?
Genital herpes is transmitted via vaginal fluids, skin contact and contact with open sores, as well as the placenta.
The medicine works by suppressing viral shedding and spreading of the herpes simplex virus. It also helps to speed up the healing of active lesions.
Patients usually begin to take Valtrex during the last month of pregnancy at a dose of 500 mg twice a day.
Valtrex suppressive therapy should be prescribed alongside precautionary measures. These include using condoms and dental dams during sex and avoiding contact with affected areas.
Women who experience herpes outbreaks during the final month of pregnancy are usually recommended to undergo a C-section to avoid infection of the child during vaginal birth.
Is it safe to take valacyclovir while pregnant?
The safety of valacyclovir is well established. Various research studies have shown that valacyclovir is safe when taken during pregnancy.
In a Danish study of 1,804 pregnancies undergoing antiviral therapy, 2% and 3.1% of infants were diagnosed with birth defects after taking acyclovir and valacyclovir, respectively. However, it’s important to bear in mind that not all birth defects were a consequence of taking antiviral drugs.
No data exists to determine the safety of taking famciclovir during pregnancy.
Valtrex and breastfeeding
Your doctor may recommend suppressive therapy to continue after pregnancy, especially if you are breastfeeding. That’s because infant exposure to HSV 1 and HSV 2 is possible via skin contact with the mother.
Taking Valtrex while breastfeeding is generally safe. Studies have previously measured the concentration of acyclovir (the active ingredient in Valtrex) in breast milk and found only small traces of the drug (less than 2%).
Urine from infants of mothers who received valacyclovir twice a day (500 mg) did not contain traceable amounts of the drug. The babies also did not show any signs of negative effects, but they did have a smaller risk of eczema and oral thrush.
Valacyclovir while pregnant
Valacyclovir is safe during and after pregnancy and whilst breastfeeding. It is not recommended to take any medication longer than necessary.
Speak to your doctor or healthcare advisor if you have or develop herpes during or after pregnancy.
- Kang, S. H., Chua-Gocheco, A., Bozzo, P., & Einarson, A. (2011). Safety of antiviral medication for the treatment of herpes during pregnancy. Canadian family physician Medecin de famille canadien, 57(4), 427–428.
- Wood S. (2011). Answering questions about herpes in pregnancy. The Journal of perinatal education, 20(1), 61–64. https://doi.org/10.1891/1058-1243.20.1.61
- Pasternak, B. (2010). Use of Acyclovir, Valacyclovir, and Famciclovir in the First Trimester of Pregnancy and the Risk of Birth Defects. JAMA, 304(8), 859. https://doi.org/10.1001/jama.2010.1206
- Drake, A. L., Roxby, A. C., Kiarie, J., Richardson, B. A., Wald, A., John-Stewart, G., & Farquhar, C. (2012). Infant Safety during and after Maternal Valacyclovir Therapy in Conjunction with Antiretroviral HIV-1 Prophylaxis in a Randomized Clinical Trial. PLoS ONE, 7(4), e34635. https://doi.org/10.1371/journal.pone.0034635
- Drugs and Lactation Database (LactMed) [Internet]. Bethesda (MD): National Library of Medicine (US); 2006-. Valacyclovir. [Updated 2018 Oct 31]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK501262/