Yes you can and no it won't hurt the baby

Unless the doc tells you otherwise. I was highrisk and was told to abstain from sex for the first tri as I had had miscarriages before.

You can have sex throughout the entire pregnancy. Your baby is in your uterus way up there not in your vagina therefore your baby does not even come close to being in contact with the penis. The only thing is when you orgasm you will get some cramping because your uterus is contracting.