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Underactive thyroid and pregnancy

(325 Posts)
cumbria81 Fri 20-Nov-09 11:20:43

I was diagnosd with an underactive thyroid last year and have been taking thyroxine. I have never had any of the usual symptoms (I don't have a weight problem and rarely feel tired) so the diagnosis was a bit of a surprise.

However, I am now thinking about ttc and know that hypothyroidism can cause problems in pregnancy. I've been doing some googling (always dangerous!) and it's quite scary - miscarriage, birth defects etc.

Has anyone with an underactive thyroid been pregnant and what were your experiences?

many thanks!

Heated Fri 20-Nov-09 11:32:31

I've read that having an under-active thyroid can interfere with ttc but have fallen pg instantly each time so have no experience of that myself. Am expecting baby no 3, although very early days.

They will keep an eye on your thyroid levels throughout pg and usually up the amount of thyroxine during pg. They will also scan you probably at least twice more than the routine scans to keep an eye on the growth of your baby. Both my two were a sensible weight and in fine fettle.

One other thing to bear in mind is that having an under-active thyroid can apparently interfere with milk production if you're intending to bf - something I only heard about after having my two. Don't know a lot about it - nor do the professionals either - so am off to investigate.

Good luck with ttc.

evitas Fri 20-Nov-09 11:57:56

Hi Cumbria81,

I had hyperthyroidism a few years ago. Although the values were ok on my last blood tests, my mw booked me an appointment at the hospital so I can talk and be seen by a obstetrician. I guess that as long as they monitor your values and they check baby on a more regular basis everything should be fine.

Good luck. All the best

memorylapse Fri 20-Nov-09 14:36:33

I have hypothyroidism and was closely monitored with my DD2, the real danger with hypothyroid is that if your TSH is not kept suppressed..there is a risk that the baby may be born with underactive thyroid too..but you will be well monitored in pregnancy and my TSH was checked monthly..Im now 16 weeks pregnant and my thyroid is checked monthly

EldonAve Fri 20-Nov-09 14:39:09

basically as soon as you find out you are pg your dose should go up 50 mcg

I will try and find the nhs clinical guidance link for you later

EldonAve Fri 20-Nov-09 14:54:45


Shauri Fri 20-Nov-09 21:05:38

I was diagnosed last year (already have 2 DC before diagnosis) Since I have been taking thyroxine I have managed to get pregnant 3 times (2 miscarriages due to a swift rise in TSH levels at week 5/6) I would recommend speaking to your Dr before getting pregnant and get them to check all your bloods - underactive thyroid can also leave you with an iron deficiency.

Not all bad news, I am currently pregnant (11 weeks) and have been having weekly/fortnightly blood tests since i found out at 3.5 weeks after LMP ( I tested early on DRs advice) The endocronologist suggested the ideal TSH level was around 1 and shouldn't go above 2 in pregnancy.


ArthurPewty Fri 20-Nov-09 21:15:48

Message withdrawn

chubbychipmonk Fri 20-Nov-09 22:05:23

Ive been on thyroxine for an underactive thyroid since I was 16 (am now 31). Take 100mcg thyroxine daily and am 35 weeks.
No problem getting pregnant, have to get my blood taken every 4 weeks to monitor my thyroid levels, thyroxine was increased to 125mcg at start of pregnancy but now back down to 100mcg.
As long as you get your levels checked regularly throughout your pregnancy you should be fine smile

cumbria81 Sat 21-Nov-09 08:44:13

Thanks for all your responses. I already take 100 mg so I suppose that would have to increase if I fell pregnant.

I think I have a tendency to fear the worst and am really not sure I could handle a miscarriage especially in late pregnancy. But I know there is no point thinking "what if".

EldonAve Sat 21-Nov-09 10:25:21

it is worth getting it checked when you start ttc as you want TSH under 2

brightonpebble Sat 21-Nov-09 10:58:24

Heated -

Interesting to hear there may be a link between underactive thyroid & milk production. I was unable to produce enough milk for either of my DCs. The first time I put it down to a difficult delivery & stress, the second time everything was ideal and had a Doula/BF expert in the house every day, did everything possible, and still couldnt make it work. No one ever had any explanation for it, maybe the thyroid was a factor.

MumNWLondon Sat 21-Nov-09 19:22:03

Hi Cumbria - get thyroid checked whilst TTC, it should be between 0.5 and 2, ideally around 1. Then you need it checked esp at start of pregnancy every month, you will need dosage changed if TSH creeps above 2. I was on 100mcg, then up to 125mcg (as soon as I conceived) now take 125mcg x 3 days a week and 150mcg the other 4 days as TSH crept up to 2.28, but now back to 1.14.

ArthurPewty Sat 21-Nov-09 20:58:47

Message withdrawn

silki Wed 03-Mar-10 22:29:45

i didnt know that FT4 is so important. I have 2 miscarriage (i lost it at 6 weeks for both). Normal range for FT4 is 0.8 - 2.0 . For both my miscarriage, my FT4 is 0.86 and 0.96 . Although the value is within range, its still on the low side. Could this be causing the miscarriage? My TSH is less then 2. My gyn is rulling out that my thyroid is causing the problem. Pls help.

santabringmeababy Thu 04-Mar-10 08:47:32

This is a really interesting thread and funnily enough I was just about to start a new one on the same subject.

My thyroid has been 'playing up' for nearly 15 years, basically swinging between overactive (never enough to require treatment) and underactive.

Eventually last year my GP tested for antibodies and found i have a very high amount which suggests I have hashimotos disease, basically where my own body is slowly killing off my thyroid.

Am currently pregnant with DC 2 (14 weeks).
Fell pregnant with this one and my DS after one try blush so it doesnt seem top have affected my fertility.

On the flip side had a very long birth with DS and my labour basically 'stopped' at 8cm for no apparent reason. having read the recent research it seems that even mild hypothyrpoidism can affect the progress of labour which is interesting. I also failed to Bf my DS despite all the 'help' and 6 weeks of heartache.

Anyway, saw the endocrinologist and obstetrician yesterday and dont need my dose increased. The endocrinologist basically said that as long as the lack of thyoxine is properly corrected there should be no risk to the baby. Not sure what my last T4 was (one a few weeks before was 14.9) but last TSH was 1.6 and he seemed happy with that.

I will be having some extra growth scans at 28, 32 and 36 weeks and weekly monitoring of babys heartbeat. Only need my Thyroid tested every eight weeks according to the Doctor but as i am only on a low dose and I seems to have BETTER levels of T4 and lower TSH since pregnancy (bizarrely)so I imagine they are not concerned.

santabringmeababy Thu 04-Mar-10 08:50:58

Cumbria 81, meant to say that having an underactive thryoid doesnt in itself lead to adverse outcomes, the most dangerous situation is having an UNDIAGNOSED underactive thryoid which of course can cause problems, but as long as you have adequate replacement therapy everything should be fine!! wink

MumNWLondon Thu 04-Mar-10 11:10:38

Risks are with undiagnosed / untreated unactive thyroid, not with one that is being monitored. I also have hashimotos.

Problem is both TSH and T4 tend to fluctuate - TSH fluctuates during course of day so best to get your blood test done first thing each morning (or at least at same time of each day). My T4 also fluctuates up and down - between 14 and 20 seems to be random.... so for me TSH is more stable (always get blood tested first thing around 9am) - if I had my dose adjusted when my T4 was slightly low I'd be over overreplaced. It just seems to correct itself.

I have beeen advised 4 weekly blood tests from 5 to 25 weeks. Highest risk time is first trimester. If all normal and stable at 25 weeks then can have less frequent checks after that point - although I am continuing with the blood tests as GP is happy for me to do so - esp as I want to make sure its all at the right levels for the birth. I had one at 30 weeks and will have one final one at 36 weeks.

The reason for the 4 weekly checks is that esp in early pregnancy things can move quickly even on a low dose eg in my first pregnancy on 50mcg TSH was 0.87 at 4 weeks and then 13.8 and 8 weeks.

Santa: T4 of 14.9 is towards the low end of normal so you might want to push for checks more often - the guidance I have read is that during pregnancy it should be above 16.

I have never been offered extra growth scans though - endo has always said that provided thyroid under control no other risk factors.

Silki I am sorry for your losses - i have been advised to increase dose by 25mcg per day from day I get BFP to make sure enough extra thyroxine in early pregnancy - I have seen this since on official NHS guidance - perhaps worth discussing with doctors just incase?

WhiteRoses Thu 04-Mar-10 12:54:35


Just thought I'd add my experience, although I'm no expert. But when I was thinking about TTC, I wanted all the information I could get my hands on!

Firstly, I was diagnosed with hypothyroidism over seventeen years ago. (I was only seven, so very young!) I've been on thyroxin ever since, and the dose has been stable for as long as I remember - certainly over ten years. However, although my thyroid was well controlled, I did have very irregular (anything between 19 and 49 day!) periods, which was a worry.

Before starting to TTC, like you, I read a lot, and scared myself senseless! Fortunately though, I fell pregnant in my third cycle. Spent an absolute fortune on HPTs, because I wanted to make sure I found out asap, so that I could get to the doctor asap! confused

When I got my BFP, I was in two minds about whether or not to up my dose of thyroxin before seeing the doctor. (Most of what I read seemed to be suggesting that you take an extra 50% of your regular dose, asap.) However, I held off and saw the doctor within a couple of days. He was great. Took blood and sent it off to be tested urgently. However, he did advise me, to my surprise, to stay on the dose of thyroxin that I was on until the results were back. His reasoning was that the effects of a new dose don't kick in for 6-8wks, and waiting 48hrs for the results wasn't long in comparison. And there was a chance that I mightn't need my dose upped, in which case I'd be messing with an already stable dose for no reason. Sounded quite logical to me.

Anyway, when the results came back (within 36hrs), he phoned me. My TS3 and TS4 levels were alright, but TSH was way off, so I did need a higher dose. I was put on that immediately, and advised to have my levels tested again 6wks later. That was Tuesday, so I won't get the results now until later this afternoon.

Now for the pregnancy itself... I've been told I did well to get pregnant as quickly as I did (three months). But then that's not bad even if you haven't got an underactive thyroid. I have felt absolutely exhausted since getting pregnant (don't thinkk I mentioned I'm currently 12wks). Tiredness is a symptom of both pregnancy and hypothyroidism, so I'm not sure of the exact cause of mine - maybe it was a bit of both? Aside from that, I've also hadd very severe morning sickness. (All day sickness.) I've been hospitalised twice in order to be treated for dehydration. Apparently (unfortunately) this is very common in hypothyroid mums-to-be. But hopefully it'll ease up soon, as the placenta takes over and as my thyroxin dose stabilises again.

The other impact of hypothyroidism is that I have to have consultant-led care, rather than midwife-led. To be honest though, I'm fine with that. It's nice to think I'm in the safest of hands.

Risk of miscarriage was certainly higher because of my thyroid, but, now that I've had my 12wk scan, my consultant has said that he's not overly concerned about me. Yes, my risk is still higher than other women's, but I don't drink, don't smoke, am a normal weight and am young (24), so all of these factors lower my risk and overall, I'm not THAT much more likely to miscarry any more than any other woman would be.

So I don't know your situation but maybe cutting out alcohol, cigarettes and eating healthily would be a good idea? (If you haven't already done this!)

I had read about potential trouble with breastfeeding, and questioned my consultant about it on Tuesday, but he seemed to think it was best not to worry too soon. That, up to now, I've had no problems (aside from sickness, which is bad for me but fine for the baby). He assured my that my thyroid would be well monitored throughout my pregnancy. He said I shouldn't be concerned if I end up on three or more times my original dose by the end. But that once the baby's born, I'll need less again, and that'll all be monitored. He reckoned that with careful control, there's no reason I won't be able to try to breastfeed.

This is a LONG post! Hope it was interesting for you though, and not just too much information! confused

Good luck though!

WhiteRoses Thu 04-Mar-10 13:03:57

Also, Cumbria, when TTC, I found this thread an invaluable source of support... All the women on it are TTC their first babies, and it's great to be able to ask questions and obsess together! There's also a "graduates" thread, for those of us who are currently pregnant, and there are plans for another thread, once we all start having our babies. So it's nice to feel you're going through it together. There are new people joining all the time too, so no need to be shy. You'll be made more than welcome if you feel like dropping in.

silki Thu 04-Mar-10 13:13:30

MumNWLondon: Thanks for your great advice. I have hyperthyrodism and was treated with antithyroid medicine. I stop medication when my thyroid level reach the normal range.

However, it looks like my level is so low and it could be hypothyrodism. I dun understand why my gyn is not acknowledging this. I will discuss with her again whether i should take thyroxine as soon as i get pregnant again.

I also have elevated thyroid peroxidase antibody (TPO) = 93, I'm not sure whether this can cause miscarriage?

MumNWLondon Thu 04-Mar-10 13:26:43

Whiterose - congratutions on your pregnancy.

Although I had consultant care in my first pregnancy by my 2nd one (and this one) I decided to opt for shared care (ie GP and midwife) just because I didn't want to be labelled as high risk and because consultant appointments in my hospital involve junior doctors and lots of waiting- its a personal choice and certainly in a first pregnancy very sensible to have consultant care. I did get transferred out of consultant care at 28 weeks in first pregnancy as wanted to use the MLU for birth and this wasn't available to women having consultant led care.

As you are being monitored and have passed 12 weeks I would have thought risks were pretty similar to everyone elses.

On the point about increased dose - with me on my first pregnancy my TSH and T4 were both totally normal at 4.5 weeks so no increase to the dose was suggested. But by 8 weeks when it was first checked in at the endo clinic as part of the consultant lead care in the hospital TSH was up to around 14, and it took 2 dose changes (effectly dose doubled from 50mcg to 100mcg and then up to 150mcg) it took until 20 weeks until it was under control again (ie TSH around 1 - after 6 weeks (on 100mcg) ie at 14 weels it was still around 6).

Interestly in 2nd pregnancy increased dose on day of BFP and didn't need any more adjustments right to end. This time I did need another small adjustment.

The point about the 6 weeks its not quite right - the extra thyroxine is effective in the body immediately but it can take up to 6 weeks for your TSH to stabilise after a dose change. I have found though for me it only takes around 2-3 weeks.

Anyway my issue I think was that I was tested too early initially - only day after BFP - I suspect had I been tested a week or so later the TSH would have started to rise already and my dose would have been adjusted sooner. Anyway my DD is healthy so I guess it doesn't matter.

When you say doctor is that GP or endo? I have found that GPs are not very knowledgeable about pregnancy and hypothyroidism - eg when I ask for increased dose at 5 weeks - GP wanted to test blood first - but luckily I could refer her to letter from endo saying I needed it immediately (letter is on my notes written after first pregnancy), plus when my TSH hit 2.28 at 12 weeks GP said TSH and dose was ok but I asked endo as I knew it shouldn't go above 2 and he increased it.

After my first pregnancy the consultant said that because of what had happened in any subsequent pregnancy to increase dose immediately because of what had happened first time round.

Anyway other than the thyroid tests both pregnancies with DD and DS uneventful, both births straightforward (esp DS's) and both breastfeed well. I was tested post-natally at 6 weeks and cut dose after birth.

Interest point about the morning sickness - mine was much worse in my DD pregnancy when my TSH was a little high - hardly had any this pregnancy (DS2) or with DS when thyroid more under control BUT that might be for other reasons eg girl pregnancy vs boy pregnancy or otherwise?

ANyway good luck and I hope your blood tests results are good - if your TSH is above 2 and GP says its ok insist on seeing specialist - and if its above 1.75 insist on test again in another 4 weeks.

Sorry for ramble hope its helpful.

Daynee Thu 04-Mar-10 13:47:35

Hey all - Just thought I'd add my experience here. I have hypothyroidism. I had 4 mc's, one of which I know for sure was a chromosomal issue. The others I don't know. At the time, my level was high because I wasn't on meds but now I'm on levothyroxine, and my doc advised me to take 2 every other day, so essentially I'm taking 50% more. Seems to be doing the trick...

I haven't heard of this being a major issue in abnormalities except I have heard that babies might suffer from intellectual development issues (learning disability) if your levels are too high...

lovechoc Thu 04-Mar-10 14:15:01

I've had hashimoto's, got diagnosed around 5 years ago now. I take 25mcg thyroxine daily and haven't found it awfully difficult to conceive although my periods have always been irregular and this hasn't helped it happen quickly like other couples.

I've had one trouble-free pg in 2006/07 and currently pg with no2 and so far no problems with the baby or myself.

I think it depends how severe your hypothyroidism is as to how the pregnancy goes. My form is mild just now but have been told I will go completely underactive eventually.

Oh, I had a MC last year, but that may be unrelated to my health problems. Just thought I'd add that in though.

piesey Thu 04-Mar-10 14:18:26

Hi there

I have hypothyrodism diagonsed about 18 months ago (I was very tired but no weight gain or other symptoms) and since then have been on a very low dose of levothyroxine (25mcg).

I'm now 6 weeks pregnant (my first pregnancy) and just been to the doctors. She didn't seem overly concerned about my thyroid and I'm going to get my bloods done next week (although she said there was no rush). My bloods we last done in November and I'm slap bang in the middle of the scale so she said she's happy that I'm probably still fine so hasn't changed my dose. I'm pretty tired at the moment but think this is the pregnancy rather then my thyroid. also not been offered any scans/test other than the usual.

She didn't mention about an increased risk on MC or other problems but now I'm a bit worried about this...

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