Hello. I was just wondering how long does metformin take to show improvement? I have been taking it, 500mg 2 weeks, for my fasting numbers (I’m usually 96-98) and they want them to be under 90. My numbers have not improved. Doctor now wants me to take 1000 mg. Anyone have any idea.


I have Type 1 and I’m not sure metformin really has much impact on my BG other than helping with my dawn phenomenon. So I’m probably not the best person for input. However, I think 500 mg per day is a pretty low dose. I’m taking 2,000 mg per day, and I think the maximum dose may be even higher than that (though I could be wrong).


I’ve been doing 1000 mg per night now for close to a month. I notice that my fasting will pike at around 5am 98 which happens to be when I wake up for work but on the weekends if my cats allow me to sleep in by 8 am I am below 90 again. I believe this is the Dawn phenomenon. Not sure what I can do to get my numbers under 90 at 5 am. Plus I don’t understand why because I’m pregnant all my numbers must be lower then non pregnant individuals. Very frustrated.

Any ideas? Exercise in the evening does help but still not under 90.


@Chubbs.mama, I don’t think that being briefly at 98 is a problem. Where does your PCP want you to be?


They want my fasting under 90. Something I can achieve this by working out in the evening but I’m 6 months pregnant and tired. I can’t always do this plus walk after every meal!


I would consult with a second Endo who specializes in pregnancy.


@Chubbs.mama, it does not seem to me that such a small difference would be of significance: after all, you are within the margin if error of the BG meter.

Can you get a second opinion? I like what @Thomas is suggesting, that would be ideal


I think the lower target is based on potential impact to baby.


Very helpful thanks.


Well I had to change obgyn because the first one wouldn’t even talk to me about different meds. I wanted to be on insulin since it doesn’t cross the placenta but her response was oh I don’t want to confuse you. I am not confuse.
In 2 weeks I meet with my new obgyn. Hopefully he will be more helpful and understanding.




Good plan. Let us know how it goes?


Well I saw my new obgyn. He answered all my questions and has increased my metformin since my fasting are now between 98-100 average. They are getting higher no matter what I do. I honestly feel like the metformin in not working. I started taking 1500 mg about 2 nights ago and no change in numbers. I’m afraid if it doesn’t get better I’m going to be put on glyburide instead of insulin.


Metformin may take 4-5 days to reach full effect.


It does seem like you are heading towards another medication change, since your fasting numbers continue to climb.

I congratulate you, having diabetes and a pregnancy at the same time doesn’t sound like much fun at all.


My MD got back to me today. So even though this whole time I’ve been asking for insulin, they’ve been telling me no oral meds are easier. Now that I say ok I’ll try glyburide they say no let’s add insulin to your metformin. SMH. I’m waiting to get my appointment. Hopefully it’s soon.


I started my NPH insulin about 2 weeks ago. It was 6 units with 1000 mg of metformin. At first it was working. My fasting were under 90 or close but then they started to increase. So my OB specialist told me to stop the metformin and go to 8 units of the NPH. Again the first night it worked but today taking I’m at 97, too high for pregnancy. So does the body adapt to insulin? Is there a good time of day I should take the NPH if I am waking up at 5am? I am at 30 weeks pregnant and I know it gets harder to control my blood sugar as the planceta gets bigger.
On the plus size baby is weighing @3lbs right where she should be!


Your problem is that you wake up higher than you want, right? I believe in your situation it would work best to take it right before you go to bed.

NPH has a peak in action, so you should try to time your injection to match the blood sugar spike you are getting.

NPH can work in certain situations, like for dawn phenomenon or for meals, if you time the NPH peak correctly.

But if your blood sugar increase is more gradual because of a higher basal need at night, Levemir might be a safer alternative. Levemir has a flatter action profile. Levemir was actually the first basal insulin with category B classification for pregnancy. Maybe you should ask your doctor about it.

Have you ever tested at 2am or 3am?

If your BG is flat until 4am or 5am and only spikes then, NPH might work fine. If your BG starts to rise earlier, I would recommend a different basal.


At 3am today I was 99. I seem to be higher at 3 and gradually decrease. By 6 or 7 am I am usually under 90.


If your blood sugar peak is around 3-4am, you should take the NPH at around 9-10pm.


@Chubbs.mama, as a side note, your body does not adapt to insulin, although it may change for other reasons. My teenage son’s body response changes every few weeks, so we always need to adapt our insulin strategies, but it is not because his body adapts to insulin.

For you, it is possible that your body may change as your pregnancy os moving forward. But it would not be as an adaptation to insulin (at least that is what conventional wisdom says).

as @Eric wrote, NPH is a bit squarely to use, because it peaks fairly sharply. We have used it in the past, but only for very specific purposes. I assume that your PCP has a good reason for this choice.