Testing for gestational diabetes

[Seasalt1984]

Hi ladies, hoping someone can shed some light/reassure me!

I had 31 week antenatal appt with GP today and had high glucose reading in urine test, which I know may indicate gestational diabetes. GP seemed unsure of next steps and went away to ask someone. She came back and asked me to book a blood test at local hospital, which I've done for 6 days time (soonest I could get). I'm concerned she may have referred me for wrong blood test. The request on form is for "AC1 (HbA1c)". From what I can see online from (hopefully!) reputable sources like Diabetes UK and NHS website this shouldn't be used to diagnose GA after first trimester and I should have Oral Glucose Tolerance Test.

Does anyone have any experience of testing for GD on third trimester who can share how it was diagnosed? I'm conscious I'll be approaching 33 weeks before blood results come back and don't want it to be a waste of time!

I did try to contact midwife to check but she isn't at work again until Friday. Feel a bit stuck!

Mine was many years ago but it was at about the same time as you and was definitely the glucose test one (so no eating after a certain time, take a book etc)
Whenever you go, please ensure you get the results. Sounds obvious, but I presumed no news meant it was negative (actually it was positive but they lost the results!)

I know my trust isn't doing oral glucose tolerance tests at the moment because of Covid, so are just doing HbA1c readings instead. Could be the case with your trust? Maybe contact your midwife to ask if you're concerned.

@biggles001 @baabaaemily thanks for your replies!

I managed to speak to community midwife helpline earlier and same as your Trust @baabaaemily, they're not doing the OGTT because of covid. Good to know and put my mind at rest I'm getting the right test!

Why aren’t they doing it because of covid? That’s so weird! I had mine at the hospital, it was on a Saturday morning so I was the only person in the antenatal clinic at the time.

Hope it all goes well with the blood test!

My trust weren’t, and still aren’t doing the oral glucose test either.

I just had the fasting blood test at 28 weeks and was diagnosed with GD from that.

Also would second the poster that said to make sure you actually get your results. I only saw mine because I logged onto my nhs app and read my own results. I knew what the legend should be and could see mine were over, indicating GD, but whoever had logged the results had written negative.

It was only when I called to query it, it was confirmed that my results were actually positive due GD. Within 2 weeks on my diagnosis I was on metformin and injecting insulin daily! My planned c section ended up being brought forward to 37 weeks because of it!

That should have said I knew what the levels should be, not legend lol

Glucose tolerance test is slightly more accurate for diagnosing gestational diabetes than the hba1c but lots of hospitals have suspended the GTT due to Covid as it requires you to be immobile waiting for 2 hours in between blood tests.
Hba1c is also more useful if they did a benchmark test a few months before. Could you buy a blood glucose monitor and check your own levels at home? There are lots of Facebook groups that support and help navigate a diagnosis or lack of one with presenting symptoms.

I’m booked in for an oral glucose tolerance test at 28 weeks.

It should be an OGTT because a HBA1c is an average over the last 3 months and if you do have GD it might have only been in the last few weeks and then it could give an inaccurate result.
At least make sure they take fasting glucose levels. I would query it because It doesn’t make sense to me to do HbA1c

I had 2 pregnancies during covid and had OGTT with both of them!

Im a midwife. Ideally they should be doing a fasting glucose level on you alongside the HbA1c...I would check to see if they have requested this and if not, see if they can add it on. HbA1c isn't as accurate in pregnancy.

My trust doesn't do OGTT due to Covid and I had a lengthy discussion with the consultant that I don't really want to accept this 🙈 (as it's not recommended by Diabetes UK, Nice guidelines, etc). He didn't budge...
At least I got referred for growth scans.
I'll probably be abroad in a few weeks time and might ask a gynaecologist/diabetes consultant if I can get it done privately.

Thanks everyone for all info!

@willthewashingeverend I've spoken to my MW now after speaking to community clinic helpline to double check, she said they're not doing the OGTT because people can't socially distance at testing...seems a bit daft but apparently local Trust policy. I have had baseline at 12 and 28 week (MW told me this) so should hopefully be able to tell either way. In the meantime I'm trying to follow a low GI approach, but I know that's not exact without measuring blood glucose levels!

Thanks for advice re following up re results, will def do that next week!

I told MW and consultant that I find this 2 hours in hospital stuff too dangerous due to Covid irrelevant.
I had a miscarriage earlier this year, however it happened after my first midwife appointment where we went through all the family history.
A few months later I was pregnant again and had to do all the family history again.
I easily sat there twice for over 2 hours. Nothing has changed in between.

Can you at least ask for growth scans? This should be the minimum alongside the not so useful blood tests.

Do you know what your Hba1c was in early pregnancy/before pregnancy?
drc.bmj.com/content/8/2/e001751
There is a study comparing HBa1c and OGTT.

@peachi82 I know, it doesn't make a lot of sense. Not sure if there's been a longer term time saving/resourcing advantage not carrying them out during covid that they want to carry on with...I work for NHS and seen it in my teams too. I didn't know about growth scan so I'll def ask MW about that. Thanks for info 👍

I don't know what my earlier readings were, they must just have gone to MW

@Seasalt1984 Fasting levels are different to a glucose tolerance test. Fasting levels are just more accurate than a HbA1c in pregnancy as like a previous poster has said, the HbA1c is a measure of your glycaemic control over the last 3 months and it you have only just developed gestational diabetes then this could be a very normal reading. The fasting glucose level is just a single blood test done in the morning....you don't have the drink or subsequent blood tests like you would with the full glucose test. The fasting level is more representative of how your body is currently dealing with sugars.

@willthewashingeverend Oh right, didn't realise that! Thanks for this info. I'll try and speak to my MW again then, so confusing when you're a bit clueless like I am!

Sounds like a cost saving exercise which they are loving using ‘due to covid’ as an excuse.

I’m not sure how sitting on your own for 2 hours on the antenatal clinic while you wait for the second blood test needs to be cancelled ‘due to covid’.

It’s really bad that some trusts are sneakily doing this and potentially putting women at risk x

I would happily sit in my car for two hours and then come back in just to get the test that is recommended.
Argh.

This explains the extra blood results on my notes today. I looked when I got home and noticed some extra blood tests and one was this. I'd assumed when the consultant said I would need a diabetes test it would be the 2hr one I had last pregnancy but I guess they are not doing them so I've had a blood test instead which confused me as when I looked it up it said that it was for people who already had diabetes and not for gd... don't understand my results tho 😒 and midwife never even mentioned them x

Also have a rbg test which says uts a random blood glucose test

I had the proper glucose test this week and I was told to go home during the wait for my second blood test. I live locally so that was fine and I'm sure if I didn't they'd have let me stay or at least asked me to go out and come back instead of waiting inside