Trying to get pregnant with Hashimoto’s and an underactive thyroid
How hypothyroidism affects fertility
The thyroid hormones impact all cells in the body and are necessary for virtually all the bodily functions.
Thyroid hormones affect both female and male reproductive health — the right balance of thyroid hormones and a healthy immune system will determine one’s success of getting pregnant.
Thyroid hormones and fertility
Thyroid hormones are important in all the phases of egg growth, sperm maturation, and survival of a fertilized egg (1–3).
T3 hormone helps thicken uterine lining (endometrium), which is a prerequisite for implantation of a fertilized egg. T3 helps the fertilized egg move down the fallopian tubes towards the uterus, where it will be implanted (1–4).
An underactive thyroid disrupts the metabolism of the hormone estrogen, and it leads to the increase in levels of testosterone, follicle stimulating hormone, and luteinizing hormone. This changes ovulation patterns in women and may result in irregular menstrual cycles (5).
7 in 10 people who are hypothyroid but not diagnosed have irregular menstrual cycles. When people get diagnosed and placed on levothyroxine therapy, menstrual cycles become regular for 5 in 10 people (6).
About 4 in 10 women struggling with getting pregnant have subclinical hypothyroidism (7).
For man, an underactive thyroid can reduce sperm motility and cause abnormal sperm morphology, lower down testosterone, and other sex hormones (8–10).
Hashimoto’s and fertility
Being diagnosed with Hashimoto’s and having high levels of TPO and TG antibodies doubles the risk of fertility problems (7, 11).
With not much research done on this topic, there are still a lot of unknowns — but a general observation from multiple studies is that high antibody levels will cause problems with conceiving.
Assisted reproduction and thyroid hormones and Hashimoto’s
During the course of assisted reproduction techniques (ART) — like in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) — women inject themselves with high doses of sex hormones in order to stimulate growth of eggs containing follicles in the ovaries.
This ovarian stimulation causes a rapid increase in estrogen levels, which increases the demand for T3 and T4 and puts a massive strain on the thyroid. If taking levothyroxine, the dosage should be increased to meet this sudden and big demand for thyroid hormones (12,13), and it is best to keep TSH levels below 2.5 mIU/L even before the start of the treatment (14).
What may help?
Collaborating with your health care practitioner in order to improve your chances of conceiving can include (15–20):
Checking your thyroid function and testing if you have Hashimoto’s before starting to try to get pregnant.
Getting on the appropriate medication dose and keeping your TSH below 2.5mIU/L.
Getting vitamin D levels in a good zone: 37.5–50.0 μg (1500–2000 iu)
Getting enough selenium: 200 mcg per day
Making lifestyle changes to lower TPO and TG antibodies: a diet that will reduce inflammation and exercise to increase serotonin levels.
Download the BOOST Thyroid app to manage your thyroid health.
1. Zhang C, et al. Effects of 3, 5, 3'-triiodothyronine (t3) and follicle stimulating hormone on apoptosis and proliferation of rat ovarian granulosa cells, 2013
2. Koot YE, et al. Molecular aspects of implantation failure, 2012
3. Aghajanova L, et al. Thyroid-stimulating hormone receptor and thyroid hormone receptors are involved in human endometrial physiology, 2011
4. Oki N, et al. Effects of 3,5,3'-triiodothyronine on the invasive potential and the expression of integrins and matrix metalloproteinases in cultured early placental extravillous trophoblasts, 2004
5. Krassas GE, et al. Disturbances of menstruation in hypothyroidism, 1999
6. Poppe K, et al. Female infertility and the thyroid, 2004
7. Poppe K, et al. Thyroid disease and female reproduction, 2007
8. Singh R, et al. Thyroid hormones in male reproduction and fertility, 2011
9. Krassas GE, et al. Hypothyroidism has an adverse effect on human spermatogenesis: a prospective, controlled study, 2008
10. Krassas GE, et al. Thyroid disease and male reproductive function, 2003
11. van den Boogaard E, et al. Significance of (sub) clinical thyroid dysfunction and thyroid autoimmunity before conception and in early pregnancy: a systematic review, 2011
12. Poppe K, et al. Impact of ovarian hyperstimulation on thyroid function in women with and without thyroid autoimmunity, 2004
13. Alexander EK, et al. Timing and magnitude of increases in levothyroxine requirements during pregnancy in women with hypothyroidism, 2004
14. Garber JR, et al. Clinical practice guidelines for hypothyroidism in adults: cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid Association, 2012
15. Yoshioka W, et al. Thyroxine treatment may be useful for subclinical hypothyroidism in patients with female infertility, 2015
16. Abalovich M, et al. The relationship of preconception thyrotropin levels to requirements for increasing the levothyroxine dose during pregnancy in women with primary hypothyroidism, 2010
17. Twig G, et al. Pathogenesis of infertility and recurrent pregnancy loss in thyroid autoimmunity, 2012
18. Maraka S, et al. Subclinical Hypothyroidism in Women Planning Conception and During Pregnancy: Who Should Be Treated and How? 2018
19. Holick MF, et al. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline, 2011
20. Turker O, et al. Selenium treatment in autoimmune thyroiditis:9-month followup with variable doses, 2006