The Thyroid Disease Link with Pregnancy and Infant Loss Awareness Month

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October is Pregnancy and Infant Loss Awareness Month.

Where does this tie in with thyroid disease? 

Well, just having a thyroid condition puts you at a higher risk for losing an unborn child. 


Thyroid function and your fertility are closely linked. Abnormal thyroid levels can lead to miscarriage, pre-eclampsia, anaemia, stillbirth and the baby developing congenital hypothyroidism itself, yet many doctors don’t think to check thyroid hormone levels in pregnant women. Women with even mild hypothyroidism have double the risk of miscarriage and premature birth.

This can be especially worrying for those feeling extremely tired, brain fogged or experiencing other common symptoms of hypothyroidism such as changes in mood, sleep, constipation, muscle aches and hair loss, because while a lot of these symptoms can be attributed to pregnancy itself, they can also be a sign of a thyroid problem, such as hypothyroidism and/or Hashimoto’s. So a lot of doctors don’t think to look in to these symptoms further and put them down to normal pregnancy complaints instead.

How Does The Thyroid Affect Fertility?

Thyroid hormones directly affect the uterine lining, causing infertility or miscarriages to occur when they are abnormal. As well as complications during pregnancy, some women with low thyroid levels may even struggle to fall pregnant at all or miscarry very early on.

In the first part of pregnancy, the fetus relies completely on the mother to provide the thyroid hormones for its development. For someone with a perfectly healthy thyroid gland and function, their body is able to meet that extra demand rather easily, but in a woman with hypothyroidism and/or Hashimoto’s, her body is often not as able to. And so complications such as miscarriages can occur.

According to the Endocrine Society’s 2007 Clinical Guidelines for the Management of Thyroid Dysfunction during Pregnancy and Postpartum, thyroid medication for those with hypothyroidism usually needs to be increased in dosage, by 4-6 week gestation and may well require a 30-50% increase in dosage. [1]

And so this is why it’s extremely important for any known thyroid patients to be monitored closely and tested regularly throughout pregnancy, often every 6-12 weeks, so that adjustments to their medication can be made accordingly.

But I feel it’s important for all pregnant women to have their thyroid levels monitored (and I hope that one day this will be the case), with pregnancy being one of the biggest triggers for Hashimoto’s and hypothyroidism, so some will develop it during pregnancy specifically or even have had it before getting pregnant, and by testing thyroid levels by default we could catch it early on to reduce the risk of pregnancy complications such as miscarriage. We need to be more proactive. We could save the lives of those who would otherwise be miscarried and save the heartache that so often ensues as a result.

A study presented in June 2012 at The Endocrine Society’s 94th Annual Meeting also recommended that all pregnant women should undergo thyroid screening in the first trimester of pregnancy. I quote:

 “The study found that even mild thyroid dysfunction could greatly increase the risk of serious problems. Women with mild thyroid dysfunction had double the risk of miscarriage, premature labor or low birth weight as compared to pregnant women with normal thyroid function. They also had seven times greater risk of still birth.”

And in the Journal of Medical Screening, researchers demonstrated that pregnant women with hypothyroidism had a second trimester miscarriage risk four times the risk of women who were not hypothyroid. [3]

How shocking is that?

Blogger and thyroid advocate Hypothyroid Mom started her site in memory of the baby she lost due to her thyroid levels not being maintained correctly, and fights to stop this from happening to other women.

She says:

“On a cold snowy day in New York City in January 2009, I lay on a medical exam table on what would be one of the worst days of my life. I had miscarried at 12 weeks and was being prepared for a D&C, a surgical procedure to remove my baby… I felt my body shake and my fists clench as I stared at the image of my unborn child. From a place deep in my soul came a wail. What happened to my child?

I trusted my doctors… never once thinking they might not know everything there was to know about hypothyroidism… I would later learn that my top awarded doctors did not know enough about hypothyroidism, especially the dangers of hypothyroidism and pregnancy. Under their care my TSH reached levels far above the pregnancy recommended reference range and endangered my baby’s life…

As the medical staff prepared me for my D&C that fateful day, I vowed that I would do everything in my power to research everything there was to know about hypothyroidism and tell women everywhere.”

She says that the reason she created her blog was due to:

“babies being needlessly harmed from medical lack of awareness about thyroid disease.”

So I’m not the only one who’s passionate about talking on this topic and joining the dots.

What Are You Looking For?

The ATA recommends the use of the following TSH test ranges during pregnancy:

  • First trimester: 0.1-2.5
  • Second trimester: 0.2-3.0
  • Third trimester: 0.3-3.0

But maintaining optimal thyroid levels for all of the thyroid panel is important. These are generally recommended as a Free T4 mid-range or a higher and a Free T3 in the top quarter of the range.

I really don’t want to think about the amount of complications and miscarriages in pregnancy that will have resulted from a missed or mismanaged thyroid condition, but I do want to make others aware of its existence. I just wish all pregnant women were screen for a thyroid condition routinely to avoid any issues caused by one going undetected. Miscarriage and the loss of a child is a heartbreaking experience for many and a lot of sorrow could be saved if more attention was paid to that little butterfly shaped gland in the neck that has an influence over so many bodily functions. Including fertility.

You can click on the hyperlinks in the above post to learn more and see references to information given, but more reading and references can also be found at:

1. The Endocrine Society. Management of Thyroid Dysfunction During Pregnancy and Postpartum: An Endocrine Society Clinical Practice Guideline. Journal of Clinical Endocrinology & Metabolism 2007; 92(8)(Supplement):S1-S47.

2. Endocrine Society (2012, June 23). Mild thyroid dysfunction in early pregnancy linked to serious complications. Newswise. Retrieved July 3, 2012 from

3. Allan, W.C., J.E. Haddow, G.E. Palomaki, J.R. Williams, M.L. Mitchell, R.J. Hermos, J.D. Faix, R.Z. Klein. Maternal thyroid deficiency and pregnancy complications: implications for population screening. J Med Screen 2000; 7:127-130.

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Written by Rachel, The Invisible Hypothyroidism

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Rachel Hill, Thyroid Patient Expert and Advocate, blogger and author, has Six 2018 WEGO Health Award Nominations. She is a highly ranked writer appearing in the Top Hypothyroidism Websites and Top Thyroid Websites 2018, with relevant qualifications and certificates in Diet and Nutrition, whilst also currently studying  Life Coaching, Motivational Speaking, Reflexology and more. She has worked with The National Academy of Hypothyroidism, The BBC, The Mighty, Dr. Hedberg, Thyroid UK and ThyroidChange, to name just a few. She is well recognised as a trusted and useful contributor to the thyroid community.

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