Yes, there is info...but mainly, any GP, Midwife , or OBYN knows it is safe. They use acyclovir because it was the only one tested on pregant women. There are updated versions but they to my knowledge, were not tested. I used always the generic (acyclovir) with both my pregnancies. I had 2 healty babies and never had an outbreak during delivery, where I did have many many outbreaks during my pregnancy! DO NOT WORRY AND DO NOT STRESS!!! MANY MANY WOMEN HAVE THIS AND HAVE HEALTHY BABIES/
THere is also research to show that taking acyclovir at least a month before delivery not only protects you, but also the baby..since he will receive it also. The baby also gets all your antibodies for herpes. This is why it is really only dangerous to a woman's child where the woman FIRST contracts herpes during her pregnancy...and especially in certain months (cannot remember which but this info also widely available)
Make sure you take the dose one month before due date and that the dose is the correct dose which is the dose prescribed normally, for when a person has an active outbreak..and not just the preventative dose!! This is important. (sorry it was almost 3 yrs ago and cannot remember but think i had to take it 3x a day)
Hope this helps!!