Just curious if any of you have continued to run while pregnant with twins. I had to stop during the latter half of my IVF cycle because it became too uncomfortable, and the RE didn't want me running in the early weeks of pregnancy. I finally got the okay from the MFM to run again, but he cautioned me that it had to be slow and I needed to avoid getting dehydrated or overheated. I've since gone running twice this week and was so happy to get back to it.
I'm wondering how long it's practical to continue running. Also, even though I got the okay from the doctor, I also still feel a little nervous about whether it's safe. I just don't want to do anything to bring on cervical incompetence or preterm labor.
TTC since June 2009
BFP #1 2/22/10 M/C 6w2d
BFP #2 October 2010 CP
BFP #3 1/11/11 M/C 8w5d
IUI #1 Aug 2011= BFN
IUI #2= BFP #4 9/18/11 missed M/C, D&C 10/18/11
IUIs #3&4 = BFN
IVF #1 May 2012 = BFP! Twins!!
Fraternal twins born Feb. 2013

Re: Running during a twin pregnancy
My docs have continued to allow me to exercise at the levels I did pre-pregnancy as long as I'm not cramping/spotting or having any other issues. I asked them again at my appointment yesterday, and they're still fine with it!
I used to run a TON (I ran like 4 half marathons last summer) -- but like you, the injections and bloating made running really uncomfortable, and I've found it to be continually uncomfortable, so I keep to more stationary cardio activities like the elliptical, stairmaster and bike.
I switched to walking during my IVF cycle and had continued to walk 3-4 miles a day up until a week or so ago. You probably have a pretty short window during which running will be comfortable, but if your dr is cool with it and you feel good, I say keep it up. I just recently feel like I have hit a wall when it comes to walking for exercise. I imagine you will know when it's time to scale back.
TTC #2 since July 2010
March 2012 IVF (MDL Protocol) Started stims 3/3; ER 3/11 (9R, 8M, 7F) ET 3/16 (5dt of 2 blasts graded 3AB and 3BA, 3 frosties(!!) Beta 3/26 = 386; Beta 3/28 = 827; u/s 4/11 says TWINS! Boy/Girl Twins delivered at 36 weeks 6 days
I was a runner pre-pregnancy. Nothing crazy, but I ran consistently every week. I had to slow down during my fertility treatments as well. Once I did IVF I stopped, hoping I would eventually get the go ahead to start again. No dice. My doctor wouldn't allow it since I had worked so hard to get pregnant. It turned out that even going for a long walk exhausted me to the point that I needed to nap, so clearly, my body didn't like it.
I think if you listen to your body, you'll be fine.
I ran until 21 weeks. ( put on pelvic rest for mild placenta previa) I was running 25 or so miles a week until 18 weeks. After that I started to become really uncomfortable.
My doctors encouraged me to stay active. I wish I could have run longer, but I am glad I was able to do what I did.
Boy/girl twins born at 37w1d and 37w2d