• You are here:
  • Home »
  • Blog »
  • FREE »

Hashimoto’s and Pregnancy: How Hypothyroidism Affects Trying to Have a Baby and Why It Matters


Hashimoto’s and Pregnancy

Hashimoto’s and pregnancy are linked in many ways. Hashimoto’s is the most common autoimmune disease in the United States and pregnancy is one of the factors that can lead to it. Many people do not know that thyroid hormones can also affect the hormones that are responsible for fertility and successful pregnancies. In this blog post, I will explore how the thyroid and thyroid hormones may affect a woman’s ability to have a baby.

What Hormones Are Important for Getting Pregnant?

Before we look at how thyroid hormones can affect pregnancy, let’s review some of the basics of the hormones used to make babies and how they work.


Estrogen rises and falls and helps to orchestrate a woman’s cycle. It makes the lining of the uterus thick so that an egg can be implanted and can grow happily there. The body signals the pituitary gland which helps to control the increase and decrease of this hormone. At the end of the cycle a sharp fall in estrogen and progesterone signals the uterus that there is no pregnancy.

Follicle Stimulating Hormone (FSH)

As its name implies, Follicle Stimulating hormone stimulates the follicles in the ovaries to grow. When estrogen levels drop at the end of the cycle, FSH levels go up (this is what is called a negative feedback loop) to start the process all over again. Once the follicles in the ovaries are stimulated, one becomes dominant and it starts secreting estrogen. This is when the effects of estrogen on the lining of the uterus take place and prepare it for nurturing the egg.

Luteinizing Hormone (LH)

At mid cycle (about day 14), the lining of the uterus stimulates a large and sudden release of luteinizing hormone. When this happens, there is a sudden rise in body temperature and this is a sign that ovulation is about to happen. This surge also causes the follicle to break open and release an egg into the fallopian tubes.


When the follicle breaks open, its walls collapse and this cavity is called the corpus luteum. After ovulation, the corpus luteum begins secreting large amounts of progesterone, which helps prepare the lining of the uterus for the fertilized egg.

Human Chorionic Gonadatropin (HCG)

Made popular by the recent diet fad, this hormone is released once the egg is fertilized. It keeps the corpus luteum healthy so that it can continue to pump out more estrogen and progesterone. This keeps the lining of the uterus healthy. After about 6 to 8 weeks of gestation, the newly formed placenta takes over the secretion of progesterone.

A Lot Can Go Wrong

As you can see, a lot of things must happen to have a healthy egg implanted in a healthy uterus to make a healthy baby. If there are problems with any of these hormones or their release, then there will be problems with pregnancy and fertilization. As it turns out, thyroid hormone can affect all of these hormones.

How Thyroid Hormones Affect This Process

When women have hypothyroidism, a common problem is an increase of another hormone called prolactin. This causes less of a release of LH, and a loss of progesterone receptor site sensitivity, and a loss in sensitivity to FSH in the follicle. All of these losses lead to problems with ovulation, and they also mess with the communication to the pituitary gland.

Using birth control pills on top of this can further harm the communication and feedback loops in this system. Using herbs to stimulate the ovaries or the reproductive system will also not work unless the hypothyroid issues are corrected.

Studies have found that even mild hypothyroidism may cause ovarian problems. Testing thyroid function is very important with women who suffer from infertility, especially if they have elevated prolactin or they can’t ovulate.

Hypothyroidism may lead to low FSH levels, which may lead to immature follicles and infertility. Suppressed LH levels will often lead to problems with ovulation in timing or abnormal luteal phase progesterone levels. These changes may cause miscarriage, depression in the second half of your cycle, or migraines in the second half of your cycle.

To summarize, hypothyroidism can cause:

* A decrease in FSH release and FSH receptor sensitivity, this leads to problems with the development of the follicle and infertility

* Suppressed LH which leads to problems with ovulation and abnormal progesterone levels, this leads to abnormal cycles and infertility

* Progesterone receptor insensitivity which also leads to abnormal cycles and infertility

* Increased Prolactin, which leads to problems with ovulation, abnormal menstrual cycles and infertility

What Should You Do If You Have Hashimoto’s  and You Want to Get Pregnant?

First of all, don’t assume your OB/Gyn or endocrinologist have any idea about this. Some do, but many do not, that’s the sad truth.

Secondly, visit this website: www.hypothyroidmom.com, this is a excellent site full of great information from a woman who has been through it.

Let me summarize her suggestions because they are brilliant:

Get Thyroid Testing Prior to Trying to Conceive

Get a full thyroid panel (TSH, free T4, free T3, and antibodies if you haven’t tested for them before). Some doctors recommend the range for TSH prior to conception of 1.0-2.0 mIU/L. This is in keeping with the Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and Postpartum.

Here is their actual recommendation:

RECOMMENDATION 15 – Treated hypothyroid patients (receiving thyroid hormone replacement medication) who are planning pregnancy should have their dose adjusted by their provider in order to optimize serum TSH values to <2.5 mIU/L preconception. Lower preconception TSH values (within the non-pregnant reference range) reduce the risk of TSH elevation during the first trimester.

Chart Your Fertility Cycle

Your chances of success are better if you know your body and how it is working. Women with Hashimoto’s or hypothyroidism often have lower than normal body temperature. Keep track and find out when your body temperature goes up because, as I stated above, this signals ovulation, the best time to make babies.

Confirm Your Pregnancy As Soon As Possible

Don’t wait to have no period, buy lots of pregnancy tests and test early and often. The developing fetus relies almost entirely on the mother for thyroid hormone. Hypothyroid Mom, Dana Trentini, sums it up beautifully:

In a person with healthy thyroid function, her body is able to meet the extra demands of pregnancy to provide the fetus with the necessary hormones. In a woman with thyroid dysfunction, her body may not be able to meet the increased demand for thyroid hormone during pregnancy. According to the Endocrine Society’s 2007 Clinical Guidelines for the Management of Thyroid Dysfunction during Pregnancy and Postpartum, thyroid replacement dosage usually needs to be incremented by 4-6 week gestation and may require a 30-50% increase in dosage.

Monitor Your Thyroid Hormone Levels Frequently Throughout Your Pregnancy

This is HUGELY IMPORTANT. Because if your TSH levels or T4 levels get too low, it can seriously threaten your baby and you could lose him or her.

According to the Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease during Pregnancy and Postpartum:

RECOMMENDATION 2 – Trimester-specific reference ranges for TSH are recommended: first trimester, 0.1–2.5 mIU/L; second trimester, 0.2–3.0 mIU/L; third trimester, 0.3–3.0 mIU/L.

RECOMMENDATION 16 – In pregnant patients with treated hypothyroidism, maternal serum TSH should be monitored approximately every 4 weeks during the first half of pregnancy because further dose adjustments are often required.

RECOMMENDATION 17 – In pregnant patients with treated hypothyroidism, maternal TSH should be checked at least once between 26 and 32 weeks gestation

Bottom Line

Like so many things that involve Hashimoto’s, you need to be proactive and armed with knowledge and information to deal with your condition because many doctors and practitioners out there don’t know how to deal with you. This is why I have created Healing Hashimoto’s: The 5 Elements of Thyroid Health, an effective system for understanding and managing your Hashimoto’s. Click on the link to the right to watch my 4 part video series and learn more.


Ylostala P, Kujala P, Kontula K, Amenorrhea with low thyroid function and thyroxine treatment. Int J Gynaecol Obstet. 1980;18(3):176-80

Bruni JF, Masxhall S, Dibbet JA, Meites J., Effects of hyper- and hypothyroidism on serum LH and FSH levels in intact and gonadectomized male and female rats. Endocrinology. 1975:97(3):558-63

Marou T, Katayama K, Barnea ER, Mochizuki M., A role for thyroid hormone in the induction of ovulation and corpus luteum function. Horm Res. 1992;37 Supple 1:12-8

Akande Eo. Plasma concentrations of gonadatropins, estrogen and progesterone in hypothyroid women. Br J Obste Gynaecol. 1975:82(7):9-20


Stagnaro-Green, A., Abalovich, M., Alexander, E., Azizi, F., Mestman, J., Negro, R., Nixon, A., Pearce, E.N., Soldin, O.P., Sullivan, S., and Wiersinga, W. Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and Postpartum

About the Author Marc Ryan

Leave a Comment:

Add Your Reply