Hi, I'm a mom of 7, soon to be 8. I have done reiki to myself for my last two pregnancies and now in my current pregnancy. I find it does help with the little discomforts, as well as help me with my overall energy. It also helped me during a miscarriage I suffered last year. I agree that it did not really help a lot with nausea... but I think morning sickness in pregnancy is a way of telling you what you need and don't need at that point in pregnancy.
I have never found that it harms the fetus in any way... if anything, it can help that mom-baby connection. :) I only wish I knew about reiki and how to use it with my previous pregnancies. Congratulations on your pregnancy, and I hope you feel better soon.