First Appointment & Runners Q?

meganruns

I had my first somewhat official appointment today with my general practitioner who in turn referred me to a new OB/GYN who'll be my actual L&D doctor.

So I didn't have a any bloodwork done (I will at my OB appt on 5/27), but we talked about my current lifestyle and she answered some questions for me.

I'm pretty bummed because she told me that I shouldn't run the marathon that I'm registered for this Sunday, and that I shouldn't be running at all in the first trimester.

While I get that doing a marathon is a pretty strenuous activity, and I want to play it safe by not running it, I was surprised she said not to run at all in these first 12 weeks.  I'd thought that, if any time, the first tri was better for exercise?

I'll obviously take it up with my new OB as well, but I'm wondering - any runners out there who have talked w/ their doc about keeping up a schedule?  What have you heard about running in the first tri or throughout pregnancy?