CGM issues 3rd Tri

Has anyone using a CGM starting to have issues in your 3rd tri? Please let me know if you are or aren't having this problem so I can figure this out..

I'm at 33 wks, and although I haven't had any big trouble using the CGM before, it's starting to give me problems. The accuracy was always great, and I only calibrate at the correct times.. It just seems NOW that it's not reading my "fluids" accurately, my isig levels jump around constantly and so it gives me inaccurate readings... I'm not sure if it's scar tissue or maybe my ever growing blood volume? I've tried different sites, but I'm about to give up. Something happened between now and the 3rd tri. My endo doesn't have much experience with pregnant T1s using a CGM, so he's not much help. I'd like to keep using  it (especially during labor and delivery) but there's no point if it's inaccurate and just stressing me out.

Please help! Thank you!!

I don't have any first hand experience since I didn't use a CGM during my pregnancy.  All I know is that EVERYTHING changes during the 3rd trimester.  I hope you can figure out how to get it to calibrate correctly.  

If not, know that testing every hour or 2 during labor and delivery you'll be fine.  The cool thing about labor is that you're not eating, so there's one less variable with blood sugars.  I thought I'd have weird stress hormones during labor that would affect my glucose levels, but I was in labor (pitocin induced) for over 20 hours and had great blood sugars, staying between 80-90 the whole time. All thanks to the pump.  I left it on until I was taken into surgery for a cesarean.

I had the exact same problem with my Dexcom in the third trimester! Here are some things that worked for me:

I placed the CGM on my upper arm. I only switched arms for rotation and kept putting it in the same area on each arm.

When I changed the sensor, I made sure that I had a three hour window in which my blood sugars would be stable and in the normal range. This means that I didn't eat or take insulin during that time.

If the sensor went crazy (like 100mg/dl off), I did everything you're not supposed to do. I'd recalibrate. If that didn't work within a few hours, I'd restart. If that didn't work within a day, I'd turn it off and start completely over. Thankfully, once I started using the arm site, the CGM wasn't off by so much as often.

I also used the sensor for twice as long as suggested. Mine is suggested for seven days, but I noticed that it was accurate for two weeks. And trying to restart a new sensor after it took two days to get it right was too much of a pain!

Good luck with the rest of your pregnancy and delivery! I was able to keep my Dexcom and pump on for my scheduled c-section, and they were wonderful tools for before, during and after delivery.

I am glad to hear that others have had issues.  I am in my second trimester and the new Dexcom works way way way better than the first.  But, the only place I've ever inserted it is on my hip and that is becoming an issue.  Thank you for the arm suggestion.  Does anyone else insert it in other places that have been successful?  The Dexcom people are never helpful and always give me the same lecture about how it is only approved for the abdomen.  They do not seem to understand that that is not always possible...

I use the back of my arm (& my 12 year old daughter's).  Works great... Out of the way.  I've also used thigh (inner side of middle).

Great to see I'm not the only one having issues.. I have a minimed sensor, maybe I need to switch to Dexcom. I can only wear mine for 3 days! It's been such a pain in the "abdomen", so I'm taking a break from it and just testing every hour.  Only 4 more weeks!!

This is also great news for me! I have been a long time subscriber, but never actually replied to anything. Currently 24 weeks and I have started noticing up to 100 mg/dl differences in my meter readings and Dexcom. My basil and bolus rates are changing so constantly I don't even know what really works any more. Thanks for all the great advice!