Pelvic Pain when Running... Normal?

Hi all,

I'm 18weeks. I plan to run a half marathon at 27 weeks. I've been running 6-10 miles once a week along with a 5 mile run and 20 minute walk/runs 3 times a week. I've noticed on my long runs that I get pelvic pain. Nothing unbearable but it's very comfortable. My heart and cardio feels fine but I'm worried about the pelvic pain.

Pre-pregnancy, I ran a half marathon at 2 hours and a 5k under 25minutes. So I've been running for awhile.