Blood Sugars During Pregnancy

OK, so I had read that in the early months of pregnancy it is common to experience low blood sugars. How long after concieving will you start to notice them?

I have also read that later on during pregnancy you start to get insulin resistence. When does this occur?

Mostly I have heard high bloods sugars can cause harm to the baby. What about low blood sugars?

I was high from ovulation date until about three weeks later (five weeks preggers.)    I always have hghs after ovulatin and would run my basal rates at about 110-115%, per my endo's instructions. 

Insulin resistance starts sometime between 15-20 weeks, but can vary for individuals. 

Hope this helps -


I stared getting very extreme lows about one day before my missed period, and the day after I went so low and had a seizure and passed out, which hasn't happened to me ever in 18 years of diabetes. The whole first trimester I had to cut way back on my insulin. I am about 15 weeks now and for the first time I am not running on the low side and I am giving bigger corrections and adjusted my basal rate just a little. I guess lows aren't good for the baby either, but it is your overall A1C and the general trend that counts, everyone will still have a low or high once in a while no matter what you do. The baby does not have your direct blood sugar so a temporary set back should not hurt anything. Keeping that in mind, I am still extremely paranoid, so it is easier said than done! I still test almost every hour and have the cgm. 

Hi Rachel,

Thinking back on my pregnancy I had less of a need for insulin in that first trimester but no serious lows. I tried to stay stable by including complex whole grain carbs at each meal and avoiding fast acting sugars. Having the CGM and Pump really made a difference for fine tuning. During the last trimester I was amazed at my resistance. I needed easily 3 times as much insulin as normal and I wasn't eating that differently. Mainly the mornings were difficult. Even if I had a salad for breakfast with minimal carbs in it I'd still find myself running on the higher side afterwards. After about 12pm I'd get back to normal and react fine to the insulin. 

The best thing you can do is try to stick with whole grain/protein/fat combos to avoid spiking your BS and if you are on the pump, use your square wave function to help with AM resistance. 

While I know the highs can cause damage due to the increased need for insulin which can contribute to baby's weight gain, lows are more dangerous for you and your health is just as important. Try not to worry yourself too much... You'll have a beautiful healthy baby before you know it... even though 40 weeks seems incessantly long!

Best of health!


Just wondering what everyone's A1C's were in the year before or at the time they became pregnant?  I'm working on getting in shape and focusing on getting my A1C's in range this year in the hopes of getting pregnant in 2012.

My A1C was 6.2 when I got pregnant, I am 6 weeks now and about prior to that my A1C was 7.3 so I brought it down in just a couple of months, my docs were ok with me getting pregnant at 7.3 but were really happy for me to get pregnant at 6.2.  I also having to use less insulin, but not having any severe lows, thank goodness.  I just hope it stays this way for the rest of the trimester.

I am currently somewhere between 12-14 wks (not sure of conception, 14 wks according to last period, but measuring more like 12 wks). My A1C is 5.8%. Initially I was running high and had to increase my basal rates, but I started running low about 3 wks ago. I did have some pretty icky lows (30s), but I kept adjusting my basal rates and keeping a careful eye on my CGM. As of yesterday, I am now running high again just like when I initially found out I was pregnant. It is very frustrating right now because I am trying to do everything "right" but having trouble staying under 150 1-2 hours after eating. I do have the pump, CGM, and I am communicating with my endo weekly to adjust settings as needed. I have good days and bad days. Today is just a bad day.

The CGM is great... I really take comfort in being able to watch my trends so that I can try to have better control.

Similar to Rose, my A1C was also over 7, and then I got it down to 6.2 before I got pregnant.  I am about 6 weeks, and I have needed more insulin since about week 3.  I thought I just totally missed that phase of needing less insulin, but it sounds like it could come later.  It's great to read about what others are experiencing! 

Ugghh I had bad lows this evening....took only 1.7 units of insulin for 3 pieces of pizza and blood sugar only went up to 170...must be that little baby...I hope that I don't get these scary lows all the time...I would like to be done with the first trimester...but I'm not complaining...I could have it a lot worse.

What different story the past couple of days have been.  It seems like I can't eat anything no matter how much insulin I give and my bs will go straight up.  It is getting really frustrating.  My bs don't go up above 250 usually but I don't like that and I am scared that I am hurting the baby.  It also seems like I can't give too much insulin...and as soon as I get it down and can eat something then it goes straight back up and then takes me a while to get it back down.  The only time that it is good for a long period of time is when I am sleeping.  I always have a good number when I wake up, but then as soon as I start my day up it goes and then it will come down and then back up and then back down and then back up.  Did any of you have this problem?  I am at 7 1/2 weeks now.  Other than one or two days I haven't had those lows that everyone talks about.  Whats up with this?

Rose, how strange that your numbers are changing so much over just a couple days! I have heard though that pregnancy and T1D is certainly a roller coaster ride. I wish you the best of luck and please keep me updated! I'm not pregnant but hubby and I are TTC.

Rose, I also had/have similar issues with high blood sugars. Around weeks 6-7, I seemed to have a lot of highs in the morning and afternoon, and I also felt like I could do nothing right to control them. I actually found that once they crept up I had no hope. If I could keep them manageable, I was ok. Since my bs started creeping as soon as I started my morning routine, I started giving myself a random 1 unit of insulin before showering. That would keep them in check until I made breakfast and hour or so later. Then, with breakfast (which is typically only 15-20 carbs), I would often give myself another extra unit of insulin on top of my I:C ratio.

Then I started having a lot of lows around weeks 10-12 (I think... I should have kept a diary). Then I felt like I was constantly sucking on juice boxes, and I also found that I needed a lot more juice to get my sugars back in check. Before I was pregnant, one glucose tab would raise me 20-30 points. Now I need at least 15 carbs to raise me 20-30 points.

However, now in my 13th week, I am now experience morning and afternoon highs again. I have resorted back to my random 1 unit of insulin before shower and with breakfast. I seem to have highs until 2-3pm, at which time I bottom out unless I eat about 10 free carbs. Then I have no problem controlling my bs for the rest of the night and I can eat a decent size dinner (up to 60 carbs).

I know that we are all individuals, but this is my experience so far, and I hope it makes you feel less alone in your battle for perfect control during pregnancy. I fight the same battle, with crazy emotions, but I have to say my weekly talks with my nurse (from endo office) are very helpful in both adjusting my insulin needs and reassuring me that I am doing well. Good luck to you!

Thanks felineresa, it does help to know that!  I'm having talks with my endo and he is helping me to adjust things.  So we will see how it goes.  I think I am starting to have diabetic guilt in hoping that my numbers won't hurt my baby in the long run.  I go to the doctor again today and I think I will get another sonogram either tomorrow or next week.  I heard the heartbeat for the first time last week and it was so cool.  I am anxious to see how the baby is growing.


Hi Theresa,

I am new to this group but SO glad I found something online!

I am/was going crazy with all issues with my blood sugar.

I am currently 5-6 weeks pregnant and I had to increase my basal rate as I my sugar was not coming down.

I thought I was the only one,  all I heard was that your blood sugar goes very low in the first trimester and I am experiencing the opposite!

I have been a diabetic for 26 years, on the pump and glucose sensor and I am quite well controlled. On top of that I test almost every hour.

I am stressing really badly as I had a miscarriage 2 years ago at 7-8 weeks.

I am still nervous but at least I am not the only one struggling with this ;)


Hey Noelle!

I am currently 7 weeks and having the same issues with my blood sugar. My endo increased my basal rates during the day and lower them at night. I have been so frustrated with having highs after I eat, but I found if I take 2 units before I eat and then whatever I need after it has been alot easier to keep in range an hour after eating. I have my first appointment with the high risk obgyn tomorrow so i'm excited to see what they think will help. It just makes me really nervous that my random highs (it's usually about 1 per day at about 180-220) might be hurting the baby. This is my first pregnancy and while I have been extremely strict on myself I just want he or she to be healthy. Do you have the usb where you can download your readings for your pump? I have this and I email the results to my endo once a week and this has helped with her needing to change rates until the obgyn can take over. Also I have found eating a source of protein with every meal including snacks hs helped in not having the bs spikes. Good luck and I know we can get through this!!!


Well, I completed a successful pregnancy and my baby boy (Owen) is now 3 mos old.  By the end of my pregnancy, my highest basal rate was 1.25 units/hr from 5-8am and my lowest basal rate was 0.3 units/hr from 4-6pm. I typically ran REALLY high in the morning and low before dinner. My I:C ratio was really tight in the morning (I think like 1:6). I averaged 150 carbs/day and I tried to eat no more than 30 carbs at a sitting. My diet was really strict and I maintained an A1C of 5.0, and actually dipped below 5.0 once. My delivery was very successful and the baby's blood sugar was perfectly fine after delivery. He weighed 6 lbs 6.8 oz and was completely healthy. I had no complications during pregnancy. My only complication during delivery was that the baby's heartbeat starting going really low during contractions when I was about 6cm or so dilated. It got a little scary at the end and they rushed people in to make it happen more quickly, but the baby came out on the doctor's first try with the vacuum and you could barely see the mark on his head. Overall, it was a complete success! So, you can have a very healthy pregnancy and delivery. Just hang in there and be really strict with your testing and diet for 9 mos and it is totally worth all the trouble!

Congratulations Theresa on your healthy baby boy!

I am 26 weeks along and my insulin needs have basically doubled. In the morning I have to take 1unit:3carbs, plus an extra 4 units no matter how many carbs I eat, just to help prevent my blood sugars from skyrocketing!! Do you mind sharing how high REALLY high is? I feel like everyone has a different definition. I have daily readings in the low 200s, and occasionally I go above 250. Even when everything is good I tend to run at least 100-120. My last A1C was 6.2% and everything has been looking great on ultrasound. My endocrinologist, perinatologist, and OB all seem happy with how things are going and keep telling me not to worry.

In terms of carbs, my diabetes educator/nutritionist wants me eating at least 220carbs per day, and at least 45g at lunch and dinner (pre-pregnancy I would limit myself to 30g at a sitting). I have tried to meet these goals, but it means I am taking a ton of insulin and watching my CGM closely to see what goes on after meals.

Again Theresa, thanks for letting us know about your successful pregnancy. This is my first, and it's great to hear first hand that everything can go smoothly for mom and baby!

You have no idea how much relief I have in reading this post Rishmack! My numbers will be absolutely perfect except in the mornings! My fasting numbers have been bad but then when I get past about 9-10 they're better. AND I have been getting up at 3 every morning just to see if maybe I am dropping in the middle of the night and my body is trying to fix and pump glucose in my body. Like last night I woke up checked and it was 128, I get up at 7 and it was 228! And then I could eat one piece of toast and one piece of sausage, correct for it with my normal correction 1:10 and it's still low 200's an hour later even after I correct for the 228. I'm on a pump so i'm going to suggest to my doctor friday that maybe we should raise the basal rate after 3am. I thought it was just me because most people are having insulin sensitivity at my stage and I am 8 weeks, but it's the complete opposite (or at least in the mornings). Thank you!