Lmao I love this question haha
Lol I love the conversation
I've never thought about the smell for baby but I have wondered how loud it is for him. Lol
The fart won't go through to the placenta. The only thing that will reach your baby is the nutritions from your blood after the placenta has sorten it out.
The thing about farts is that it is gas, aka leftovers, from the intestions that the body need to get rid of. If it was possible for the baby to smell it that would mean that the body wouldn't do such a good work, but it is a really good cleaning machine so don't worry ;)
If baby could smell, the baby will smell way worse than a fart
Lol, I don't know but pregnancy sure makes our bodies and minds act weird!