As far as I know there is no clinical evidence that Botox injections while pregnant can affect the fetus. Having said that I would not advice any woman to get Botox injection if she even suspects that she might be pregnant.
Botox is not recommended in pregnancy or while breastfeeding since we really do not know if it can cause any problems. It will not likely be an issue for you or your baby but I would just let your Obgyn know and plan to wait until after delivery or breastfeeding to have further treatments with Botox.