I have hypothyroidism, and all of my pregnancies were only successful once I had my thyroid levels at a good level, under a TSH of 2.5. I’ve shared my exact levels below. Hence, I strongly believe that there’s a link between thyroid function and successfully conceiving and sustaining a pregnancy, perhaps even beyond what is currently known and proven through research. My experience with hypothyroidism is quite diverse, and I have a fair few thoughts about it that I’ve shared below.
As a side note, I’ve recently learned that good thyroid function is also associated with helping manage postpartum hair loss, which I felt like I had a great experience with for the twins, so this could have been a factor too!
Thyroid medication may have saved my first pregnancy
My thyroid function plummeted when I fell pregnant with my first, so I had to start levothyroxine immediately at the 4-week mark. My doctor had actually told me that I would likely lose this pregnancy as he ordered progesterone testing alongside my hCG and saw that my progesterone levels were quickly dropping. Yes, I was an absolute wreck having been told this. In the end, this was a successful, full-term pregnancy that I delivered at over 41 weeks. It is only in recent times that I’ve learnt about the link between thyroid hormones and progesterone production. It’s safe to say that I’m really glad I started levothyroxine when I did – and I do believe that the thyroid meds could have contributed to this being a viable pregnancy – in part due to the next point.
I didn’t know the link between having subclinical hypothyroidism and pregnancy
I was diagnosed with subclinical hypothyroidism years before wanting to start a family. Because it was subclinical, meaning that my TSH was just slightly elevated outside of the ‘normal’ zone but my T4 levels were normal, I didn’t need to take anything – just keep monitoring my levels every 6-12 months. What no one ever explained to me at the time was the importance of healthy thyroid function for pregnancy. Specifically, the important role that the thyroid plays in ovulation, conception and sustaining a healthy and viable pregnancy.
So when I first fell pregnant (with the baby I miscarried at 6.5 weeks), I didn’t worry very much at all about not being able to get in with my doctor (due to the Christmas holidays and office closures). My thyroid level was never tested. I assume that my levels would have dropped too, but unfortunately, I was not on any medication and knew very little about thyroid health. Naturally, I do wonder if my unmanaged hypothyroidism contributed to the miscarriage but that’s one of those things that no one will ever know, and it just is what it is.
Getting my TSH level within range for pregnancy allowed me to conceive twins
Again, this one has to fall into that “I guess we’ll never know” category, but when we decided to have another baby, I got my bloodwork done including checking my thyroid levels. My TSH was lingering around 3.0-3.2. This is actually within ‘normal’ range, but my doctor said that for pregnancy, we ideally want the levels sitting at below 2.5.
Here’s the thing: we tried for many months for a (single) baby unsuccessfully, and then the very first month that my thyroid levels dropped down to a 0.45 (I was having monthly thyroid level checks), we conceived not one but two babies. I mean, of course it could have been something else, but everything else in my life was fairly consistent, so I can’t help but wonder if the two are related. And I do believe they are!
Be prepared: Pregnancy takes a big toll on your thyroid
I definitely didn’t realize what a massive toll pregnancy can have on your thyroid function and how it can lead to hypothyroidism. With my first singleton pregnancy, I went from no medication to 50mg of thyroxine daily With my twin pregnancy, I ended up on 100mg daily as my levels kept worsening.
Both times, after I delivered my babies, my thyroid levels improved greatly and I could either reduce my medication down to a very small dose or stop it altogether.
Your thyroid is important for life, too
While it may be easy to think that I don’t need to worry so much outside of pregnancy, especially now that we’ve completed our family and finished having babies, the reality is that your thyroid is also so important for keeping you healthy outside of pregnancy and supporting your body. Your thyroid works to
- Regulate your metabolism, which affects how your body uses energy
- Helps control the rate at which your body burns calories, affecting weight management and energy levels throughout the day
- Support heart health by managing heart rate and blood pressure
- Help maintain healthy skin, hair, and body temperature
Simply put, your thyroid is integral to nearly every physiological process your body does, and it’s super important to keep your levels under control and ask for monitoring if you haven’t already got it.
When I was first diagnosed with hypothyroidism, I had so many questions
After learning about subclinical hypothyroidism, I started learning more about thyroid function and understood that there was some kind of connection with fertility, but I didn’t know the extent of the repercussions, even with medical management. I took all the questions to my doctor, and these were the answers I was given – in case it helps you too.
Can having hypothyroidism affect my ability to conceive?
Apparently, yes, having an underactive thyroid can interfere with how your body releases an egg, which negatively impacts your fertility. This is only temporary though – once your levels are regulated, things tend to go back to functioning normally (or at least what is normal for you).
How can hypothyroidism affect my pregnancy?
Also yes – and for both mom and baby. For the mom, aside from feeling absolutely exhausted, there can be an increased risk of developing hypertension in pregnancy, known as preeclampsia, which can be dangerous for both the mother and the baby.
When a mom has hypothyroidism during pregnancy, it can affect the baby’s growth and development in ways that might be concerning. For instance, there’s a chance the baby could be born a bit too early (premature) or might weigh less than expected at birth. Also, in the first few months of pregnancy, the baby relies entirely on the mom for thyroid hormones, which are super important for brain development. If the mom’s thyroid isn’t working well, the baby might not get enough of these essential hormones, which can affect how well the baby’s brain and nervous system develop. The bottom line here is that keeping an eye on your thyroid health during pregnancy will ensure you’re doing everything you can to help give your baby the best start possible.
If you’re interested in reading the evidence behind hypothyroidism and pregnancy, here is an article I found helpful. Please note that it’s a medical ‘research’ type article (given I’m a medical researcher by profession) but I found it to be very helpful, even when making sure I’m providing you with accurate information here.
You can develop hypothyroidism postpartum
Another note here that I feel I need to add about reading more about hypothyroidism, is that you can develop hypothyroidism postpartum. It’s where your thyroid becomes inflamed after pregnancy, leading to its function being thrown off. Most women experience it approximately 3-8 months after having their baby and it can last up to a year. If you notice severe fatigue, fatigue, weight gain, constipation, dry skin, depression and associated symptoms, please get your thyroid levels checked!
What are the best thyroid levels for pregnancy?
According to research, my doctor was right – you really want to keep your TSH levels below 2.5, particularly for that first trimester when that important brain development is occurring. After this, it can vary by trimester, with the upper limit increasing to 3.0 in the second trimester and 3.5 in the third trimester. Another great resource to learn more about the thyroid in pregnancy is from the American Thyroid Association.
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