Caffeine??

I also had IVF.  Once a baby implants, it implants (doesn't matter how it was made at that point).  Caffeine does cross the placenta, but the placenta isn't formed until 6 - 7 weeks.  Most doctors (OB's, MFM's, etc.) say caffeine is OK in moderation -- 200 mg or less.  Soda has much less than coffee or tea.  

I have a pepsi or so a day and baby is good.  My MFM (maternal fetal specialist, the OB's on steroids) said it was fine.

i drank my diet coke everyday... i had 2 under 2... then 3 under 3.... it was a mandatory requirement if i wanted to get through my day.

I too drank caffiene, but limited the amount I would have. Now that I've had my baby, I've limited it even more and make sure to drink an extra glass of water to make up for the caffiene....as they say it dehydrates you and you need an equal amount of water and coffee to offset each other.