What is the first-line treatment for herpes simplex virus during pregnancy?

Acyclovir is considered the first-line treatment for herpes simplex virus (HSV) infections during pregnancy due to its established safety profile and efficacy. It is a nucleoside analog that works by inhibiting viral DNA synthesis, thereby suppressing the replication of the virus.

Acyclovir has been extensively studied in pregnant populations, and research indicates that it does not pose significant risk to the developing fetus, making it a preferred choice for managing HSV infections in pregnant patients. This is particularly important in preventing neonatal herpes, which can have severe complications if the virus is transmitted from mother to baby during delivery.

While other options like valacyclovir, which is a prodrug of acyclovir and has improved bioavailability, are also used in the treatment of HSV, acyclovir remains the standard initial treatment. Foscarnet is generally considered for severe or resistant cases of HSV and is not the first-line due to potential toxicity. Interferon has limited use in this context and is not a preferred treatment for HSV during pregnancy. Therefore, acyclovir is the most appropriate choice for treating herpes simplex virus during pregnancy.