Any supplements, I would ask your doc about... some are safe, others are not. Such as vitamin C, that is a no no while pregnant.
There are many studies showing some benefits such as lowering the risk for pre-eclampsia. Most doctors will probably tell you not to take anything because there's no evidence that it is safe, that doesn't mean that it isn't safe- it just hasn't been studied. But more and more studies are being done that actually show some benefits. The question is how much is safe? I would think a small dose would be fine from what I've read. Just do some research for scholarly articles and see what doses they are taking. I think less than 200mg. But look yourself because I don't know, it's just a guess based on what I've read and I'm not a doctor.
It actually helps optimize pregnancy, help prevent miscarriage, I took throughout whole pregnancy.
Garden of Life raw Co q 10
The best!
Call your doctor or obgyn. They have the knowledge and the training. They will know.