Use of levothyroxine among pregnant women with subclinical hypothyroidism in the United Kingdom: A population-based assessment

[helvella]

It feels very odd reading a paper from Canada about the UK. But they are right - a dreadful record of not recognising the need to treat.

I am taken back to post after post after post here where we have had to explain the need to do something about high TSH/low FT4. And the reference to those already on treatment who should self-administer a dose increase. (Not easy if your doctor won't increase your prescription.)

They want to know the barriers? Sadly, a lot of them have medical qualifications.

Use of levothyroxine among pregnant women with subclinical hypothyroidism in the United Kingdom: A population-based assessment

Ya-Hui Yu, Kristian B. Filion, Pauline Reynier, Robert W. Platt, Oriana H. Y. Yu, Sonia M. Grandi

First published: 13 August 2021

doi.org/10.1002/prp2.848

Abstract

Our study aimed to describe levothyroxine prescription patterns and trends over time among pregnant women with subclinical hypothyroidism (SCH) in the United Kingdom.

We used data from the Clinical Practice Research Datalink linked to its Pregnancy Register and the Hospital Episode Statistics database from 1998 to 2017. The study population included women with a diagnosis of SCH or an abnormal thyroid-simulated hormone (TSH) level one year prior to or during pregnancy. We compared characteristics between women who received a prescription for levothyroxine during pregnancy and those who did not. We further described the timing, dose, duration, and temporal trends of levothyroxine prescriptions.

Our cohort included 6,757 pregnancies from 6,287 women with SCH, of whom 10% received levothyroxine during pregnancy. Among women who received levothyroxine, most received their first prescription during the first trimester (median gestational age: 7 weeks; interquartile range [IQR]: 0, 16) with a median daily dosage of 50 mcg (IQR: 50, 73). Levothyroxine prescription varied over time, decreasing from 23% of pregnant women in 1998 to 7.5% in 2003, remaining stable until 2014, and increasing to 12.5% in 2016. Smoking, diabetes, polycystic ovary syndrome, infertility, timing of SCH diagnosis, age, TSH level at diagnosis, and general practice regions were associated with prescription.

Few women with SCH received levothyroxine during pregnancy, and treatment varied by patient characteristics and geographical regions. These results highlight the need to increase awareness among healthcare providers and will guide future studies that explore barriers to initiating levothyroxine treatment for women with SCH during pregnancy.

bpspubs.onlinelibrary.wiley...

[janeroar]

I’m curious to know the effect not having /having thyroid replacement treatment has on the developing baby?

[helvella in reply to janeroar]

The American Thyroid Association 2017 guidelines go through many of the issues.

liebertpub.com/doi/10.1089/...

Much as we tend to criticise the ATA, this document is a lot more solid than some.

[TSH110 in reply to janeroar]

I imagine pretty dire.

[helvella in reply to janeroar]

And the birth processes. One of the first posts I made here, ten or so years ago, was this:

TSH and Breech Presentation

healthunlocked.com/thyroidu...

[janeroar in reply to helvella]

It makes so much sense that of course thyroid levels are doing to affect pregnancy - like everything else.

[Hidden in reply to helvella]

This is interesting. My first born was a Brow Presentation rather than breech but I wonder if the thought could be extrapolated to "abnormal" presentation Food for thought, anyway!

[tattybogle in reply to helvella]

Nice find . why oh why do we have to put up with Doctors (who's opinion we usually didn't ask for) banging on about relatively slight statistical risks of LOW TSH giving us things we might get in older age anyway like osteoporosis and AF ....... when we never hear A WORD about increased risk of things like breech birth with higher TSH ?

Surely breech is potentially such a significant issue for baby/mother and the hospital , that you would think it was reasonable for doctors to be banging on about anything that could reduce risks for it from the first antenatal visit ..... but no, you guessed it .. i'm a trained nursery nurse , i've had 2 babies, one with the NHS, and one with a private midwife , (who was excellent) .... and yet today is the first time i've EVER heard of this increase risk for Breech birth.

Fortunately for me ,i never had a baby backwards, but if men had babies i'm sure they would be very keen to monitor their TSH if it reduced the probability ... i gather it's no fun at all.

OMG as i was writing this i just remembered my 2nd baby was the wrong way up a few days /week ? before being born ... the private midwife did that thing where they push it round the right way and you have to keep you bum in the air all day to hope the baby doesn't turn back round ..... funny how much of your life you can forget .

To be fair now that i've finished ranting ....i suppose i had mine in the 1990's before this paper came out .. so maybe they didn't know then ,, but that's no excuse for not paying closer attention to TSH in pregnancy nowadays , which they clearly still don't.

[helvella in reply to tattybogle]

Although at least back to 2004:

BJOG. 2004 Sep;111(9):925-30.

doi: 10.1111/j.1471-0528.2004.00213.x.

Low concentrations of maternal thyroxin during early gestation: a risk factor of breech presentation?

Victor J Pop 1 , Evelien P Brouwers, Hennie Wijnen, Guid Oei, Gerard G Essed, Huib L Vader

Affiliations

• PMID: 15327606

• DOI: 10.1111/j.1471-0528.2004.00213.x

Abstract

Objective: To evaluate the relation between breech position at term (>37 weeks of gestation) and low maternal fT4 levels during gestation in women not suffering from overt thyroid dysfunction.

Design: A prospective cohort study of pregnant women.

Setting: Community-based study.

Population/sample: At random selected pregnant women of the general population.

Methods: At antenatal booking, based on thyroid function assessed at 12 weeks of gestation in a large cohort of pregnant women, two groups of participants were defined: women with low fT4 levels-below the 10th centile (n= 135) and women with fT4-between the 50th and 90th centiles at 12 weeks of gestation (n= 135). Women with clinical thyroid dysfunction (fT4 and TSH outside reference range) at 12 weeks of gestation were excluded. Maternal thyroid function (fT4 and TSH) was subsequently assessed at 24 and 32 weeks of gestation. Analysis refers to 204 women who met the inclusion and exclusion criteria and in whom all thyroid parameters were assessed.

Main outcome measures: Fetal presentation (cephalic-breech) at delivery in women with term gestation (>37 weeks of gestation) in relation to maternal thyroid function at 12, 24 and 34 weeks of gestation.

Results: Breech presentation at term delivery was independently related to fT4 levels <10th centile at 12 weeks of gestation (OR = 4.7, 95% CI 1.1-19 [but not to an fT4 level below the 10th centile at 24 and 32 weeks of gestation]) as well as primiparity (OR = 4.7, 95% CI 1.3-15).

Conclusions: Women with hypothyroxinaemia (fT4 level at the lowest 10th centile) during early gestation but without overt thyroid function are at risk for fetal breech presentation at term (>37 weeks of gestation).

pubmed.ncbi.nlm.nih.gov/153...

[goatheard in reply to janeroar]

In my case, untreated (by week 3, I couldn't walk to the end of the driveway due to fatigue and spent the rest of my pregnacy in bed)... my son was born 8 weeks early by emergency C-section, with classic autism, dyspraxia, low IgA, eosinophilic esophagitis, failure to thrive, and more... and also hypothyroidism. He spent the first 18 years of his life in physical therapy, occupational therapy, and speech therapy. Also, time to take a closer look at the causes of various forms of autism instead of lumping them together, I think.

[Lovecake in reply to goatheard]

There’s a lot of Hashimoto’s in my family - and several children with borderline autism/some learning difficulties like dyspraxia etc.It could be that low Ft4 levels were an issue, but I know that none of us were tested back then. Most of us didn’t get our condition diagnosed until we were older (40s), and definitely had symptoms for years, but didn’t know a thing about thyroid problems.

[humanbean]

I'm surprised at how low the levels of treatment were in these women with SCH in the UK, even though I suffered from this lack of treatment myself.

This document is a link to 43 pages of research papers on the subject of SCH and pregnancy :

library.wmuh.nhs.uk/wp/libr...

[BB001]

This could be one consequence

Https://dailymail.co.uk/health/arti...

I'm convinced low thyroid hormones in pregnancy is linked to having an autistic child. There are just too many of my hypo friends with autistic children

[janeroar in reply to BB001]

Yes - It was neurodevelopmental issues that I was thinking of when I asked the question. Hypothyroidism is taken v seriously when a child is born; logically to me an under medicated pregnant woman poses a risk to her baby

[mstp in reply to BB001]

I developed hyperthyroidism when I was pregnant. It wasn't diagnosed for another six years which was disastrous for my family. Haven't noticed the child I had being a maths boffin in case anyone is wondering...

[helvella in reply to mstp]

There is great difficulty in fully determining the impact of maternal hypo- or hyper-thyroidism.

Before the foetus develops thyroid hormone capability of its own, it necessarily depends on maternal thyroid hormone - so the mother's thyroid status gets reflected in the foetal thyroid hormone levels.

But once the foetus can produce its own thyroid hormones, things can get more complex. It is suggested that the foetus of a hyperthyroid mother will develop somewhat less - simply because it has not needed to produce as much. And, the foetus of a hypothyroid mother might develop greater capacity.

Seems likely that the profile of thyroid hormone levels of foetuses and the newborn might diverge from some hypothetical even straight-line assumed in those without any thyroid issues.

(Obviously, I am completely ignoring nutrient levels - such as iodine. That just adds complexity.)

[janeroar in reply to helvella]

I would imagine the crucial time for the baby is pre development of own capacity to make thyroid hormone

[helvella in reply to janeroar]

Yes - that is why the widespread rule-of-thumb - increase levothyroxine by 25 microrgams as soon as pregancy is known. Which seems all too often ignored or, at least, the mother is not fully supported in doing so.

[nightingale-56 in reply to helvella]

When I was expecting my second son in 1976 the Midwife I had at the time, said that if you get a Mother with a Hyperthyroid condition, then the baby is usually born small with hormonal problems. This proved to be true when my son was born.

[janeroar]

The lack of care and respect that is so evident in the treatment of thyroid disorders is really quite shocking.

[tattybogle]

On the subject of autistic ?/ Hypo ? /Hypo mum ?

Both my pregnancies and babies have given me cause for thought (with hindsight) , but it's all conjecture as i wasn't diagnosed autoimmune hypo till 4 yrs after 2nd child.. no history of thyroid testing prior to this.

1st pregnancy ~ crippling fatigue, but nothing identifiable wrong with me.

That baby was whipped away for several minutes immediately after birth , no crying , lots of nurses on the other side of the room doing stuff. Turns out he had very low APGAR score at first , 2nd APGAR was better though, so nothing too unusual there, but then i remember he was put under a light for jaundice ... again i thought this was not uncommon , but have since found out it IS uncommon if it develops in the first 24 hrs, and is indicative of a problem that could have some connection to hypo. When we got home , he was ALWAYS asleep (great, i thought !) you had to wake him to feed him. When trying to get him to smile in the first few months he wouldn't look at you in the eye, he would actively turn his head away. As a toddler he used to scream in distress at harsh noises like the hoover or buzzers in waiting rooms , or people singing in toddler groups, despite being otherwise good natured and calm.(Still always asleep... great i thought !, if you drove to the end of Cornwall he'd stay asleep the whole time unless you stopped the car.) He had an uncontrollable fascination with red LED lights on plugs, and his first offence was switching off all the library computers while sitting in his pushchair. He always had difficulty with bowel movements until he was teenager and discovered coffee.

As a small child he was always saying he was cold, and needed to sit in the sun like a lizard before he'd eventually go off and play. He hated new clothes and the feel of cold waterproofs , in the end we put them on the radiator before playtime to avoid the fuss. If it was an unusual/ festival day at kindergarten he'd kick off and rip things up, but was fine if you let him observe without participating so we used to tell him he could spray the moss garden with a plant mister and he'd happily do that all morning instead... I often wondered if he was 'a bit autistic' ... he's fine now .. but especially since learning that 'needing light therapy before 24 hrs' is unusual.. i do wonder if i was a bit hypo during that pregnancy and perhaps he didn't have quite enough thyroid function somehow .. but he did have a heel prick test and it was fine. But with hindsight there's a lot of 'flags' there for ? low thyroid and ?autism.

I was fine for 7 yrs following that, but 2nd pregnancy ~ crippling fatigue again .but that child had none of those issues ( but was startlingly ugly for about 3 months ~ but allegedly ,so was i ~ lol )

I really wish someone had thought to test my thyroid instead of writing "Well, but Tired" on all of my maternity notes .. we might have learned something interesting.

For the life of me i can't understand why a set of TFT's is not standard practice for routine pregnancy care... and i certainly can't understand why it was never done when i was so unusually exhausted for no apparent reason.... maybe that's the problem .. i wasn't over weight , even when i was pregnant .. so maybe no one thinks of "hypo?" if you're not overweight.

[Hidden]

I had a TSH of 8.37 (9.05am) at about 4 weeks pregnant and the GP didn't even blink. Just said test again in 8 weeks. Which I did, but I didn't know half of what I know now and wasn't confident in what I did know, and had a TSH of 4.08 (11:30am). So was sent on my way.

Even when I rang up distressed about the impact having a high TSH might have on my pregnancy they were unmoved. 😔

Mercifully, I had a healthy, heavy (9lb 4oz) baby who shows no signs of I'll effect of an untreated, hypo mother.

The effect on my mental health was great though, the worry never went away.

[helvella]

Looks like the link between hypothyroidism and breech birth is firming up - but still not understood.

If you are interested, I recommend reading this in full. Brings the information up to date.

J Clin Med.2021 Mar; 10(5): 1120.

Published online 2021 Mar 8. doi: 10.3390/jcm10051120

PMCID: PMC7962442

PMID: 33800139

Delivering into the Mounting Evidence of a Probable Link between Maternal Hypothyroidism and Breech Presentation at Term: What Do We Know until Now?

Panagiotis Peitsidis1,2,* and Nikolaos Vrachnis3,4

Full paper freely accessible here:

ncbi.nlm.nih.gov/pmc/articl...