intro & a question for runners

ajetter

Hello ladies.  I got a BFP last Tuesday, and I'm guessing my due date will be around February 20th, but hopefully I'll get a dating ultrasound in a couple of weeks.  I was on CD 37 when I got the positive test.  DH and I have been together for 10 years, married for 4 and have a just over 2 year old daughter.  Glad to be joining you all and I hope I get to stick around!

My question... my cycles got longer and irregular when I started training for a half marathon last August (I did the C25K in March '11).  They used to be about 30-31 days, and from August forward, ranged from 34-53 days.  I am only assuming the running is what changed my cycle.

I was worried that some hormone levels or something might be off, so I was excited when I got the BFP (cycle #5, month #7), but worried about how continuing to run would affect me early on in the pregnancy.  I called the nurse at my OB's office and she said not to worry, just to slow my pace a bit and try and keep my heart rate in the 130-140 range.

I was comfortably holding an 8:30-9:15 per mile pace before I got pregnant, and racing at between a 7:45 to 8:10 pace.  So I figured slowing to a 10:00 minute mile would be plenty sufficient.  But my heart rate is still up in the 150+ range.  Even at an 11:00 minute mile pace.  Any thoughts?  Are you worried about your HR?  I don't feel like I'm working hard at all, and I think the heart rate thing is more of a cautionary old school suggestion, but I don't know.

Any input would be much appreciated.  Of course I don't want to do anything I shouldn't be, but at the same time I don't want to slack off or put in less effort than I could be.

Thanks!