Because there is so much more blood flow to the cervix, etc, sometimes women bleed a little after sex during the
first trimester. Walking is good for you and baby..i have never heard of walking too much being linked to miscarriage. There are some exercises that should be avoided though. rule of thumb...don't do anything that your body wasn't used to before pregnancy. Meaning, don't go out and try to run 2 miles if you're not used to running.