Digestive plant enzymes are, unless the product is a complete fraud, enzymes derived from plants -- in other words, food. They are no more dangerous than eating the plants they come from.
Now... no one ever wants to be the one to give someone advice which ultimately results in damage or death to a baby, so it's extremely rare for anyone to say that anything is safe during pregnancy. And so I won't claim that your product is 100% safe. Nothing is. And a bad batch of anything could cause serious damage.
So... you get to decide. Weigh the risks yourself.
If it's any consolation, my pregnant wife takes some. *wink*