I was on Zoloft (also 50mg per day) for depression throughout my pregnancy and have a perfectly healthy daughter. While there may be evidence of increased risk of birth defects, these defects are very rare to begin with (I can PM you links to scientific articles if you'd like). My main concern was withdrawal after she was born but BFing helps with that.

It was a huge relief to see that everything was normal at the morphology scan. DD hasn't been the easiest baby and I'll always wonder if the Zoloft has anything to do with that (but I think she's just very strong willed). I should also mention that I have developed PND since giving birth and have had my meds increased. I don't like to think about how bad it could've been without any meds at the beginning.

Its important to weigh up the risks of Zoloft vs the risks to bub if you had a panic attack/s. Whatever is best for you will be best for bub. Goodluck.