Chances of Getting Pregnant With Hypothyroidism. Everything You Need to Know!
Is your TSH level at the high end of normal? Do you need thyroid treatment for IVF? Infertility? Miscarriage? Let me give you some clear information.
I get a lot of questions from women who have a TSH level in the upper range of normal. Between 2.5 and 4. And we're told that they should start taking thyroid hormone medication like Synthroid to improve their chances for IVF success, increase their overall fertility or reduce their risk for miscarriage.
Is this something you should do?
How does the thyroid work?
First, a little background. Everybody has a thyroid gland. It's located in the front of your neck. The thyroid produces hormones which affect every body process. The two main hormones produced from the thyroid are referred to as T4 and T3.
Problems can occur if your thyroid produces too much or too little of these hormones. This is known as hypothyroidism or hyperthyroidism. Hypothyroidism is very common in women.
How can you tell if you have hypothyroidism?
Well, the thyroid is controlled by a hormone from the pituitary gland called TSH or thyroid stimulating hormone. TSH blood tests are by far and away the most sensitive and accurate way to determine if you have a thyroid problem.
If your thyroid is not producing enough thyroid hormones, your TSH blood level will go up. A TSH level between 0.4 and 4 means your thyroid is functioning normally. If your TSH level is persistently higher than 4, then you have hypothyroidism. This group of women should be treated with thyroid medication.
Should you be treated if your TSH level is below 4?
Let's look at the evidence for IVF. In 2011, doctors from the National Institutes of Health looked at over 1200 women who were undergoing IVF and who had their TSH levels measured before starting treatment.
They divided them into two groups based on their TSH level. The first group were women with a TSH between 0.4 and 2.5 which I will call the "low normal" group.
The second group are women with a TSH between 2.5 and 4 which I will call the "high normal" group. This is the group that some have claimed will reduce IVF success and should take thyroid hormone medication.
How did these two groups compare when they did IVF?
It turned out that they were identical in almost every way imaginable: they used the same amount of fertility medications; retrieved the same number of eggs; and had the same fertilization rates.
For those women that had embryos transferred, the pregnancy rates were the same, the miscarriage rates were the same and the live birth rates were the same.
Let me say that again. Women in the high normal TSH group: those with a TSH between 2.5 and 4, had IVF babies at the same rate as women with a lower TSH.
Should you treat TSH for infertility?
What if you have infertility and you're not doing IVF? Another study collected data on over 1600 infertile women. They also divided the women into two groups based on their TSH level.
They also found no difference in the odds of conceiving miscarriage or live birth when they compare the low normal and high normal groups.
Should you treat TSH for miscarriage?
What if you don't have infertility but have a history of miscarriage? A 2017 study looked at over 1200 women with a history of pregnancy loss and who were trying to become pregnant.
The study found that women with a TSH greater than 2.5 did not have a longer time to pregnancy, did not have a higher miscarriage rate and did not have a reduction in their live birth rate.
Our bottom line is this:
If you are trying to conceive and your TSH level is between 2.5 and 4 - Don't stress!!! This means your thyroid is working normally. You will not have more trouble getting pregnant and you will not have a higher chance for miscarriage.
If you are doing IVF, you will do just as well as women with a TSH less than 2.5. Do not agree to take thyroid medication if your TSH level is in this range. You do not need it!
The best way to increase your chances of getting pregnant is to take natural fertility supplements.