How Hypothyroidism Impacts Fertility

Updated: Dec 17, 2021

Thyroid disease is the most common endocrine disorder that causes fertility issues and infertility. There are a few mechanisms by which this occurs, and it is treatable if diagnosed correctly. When TRH (thyrotropin releasing hormone) is elevated (in hypothyroidism) it does its job at increasing TSH. But, it also decreases dopamine which then increases prolactin levels. Elevated prolactin can interfere with fertility by inhibiting production of Estrogen by the ovaries. Sufficient estrogen levels are vital to maturing the follicles that eventually lead to ovulation.


Low estrogen can also lead to:

+ decreased cervical fluid which causes vaginal dryness

+ Reduced sex drive

+ Irregular periods or

+ Amenorrhea

These all impact fertility and reduce chances of conception each cycle.


If you’re having trouble conceiving and you have hypothyroidism, consider a thyroid panel to see where your levels are at. If you don’t have a diagnosis of hypothyroidism, it’s still worth investigating. My preconception plan includes thorough workup of the thyroid hormones.



Specifically, Hashimotos Thyroiditis is linked to subfertility and infertility. Thyroid antibodies are found to be elevated in folks with Hashimotos, and the higher these numbers, the more inflammation is found in the body. Inflammation is known to impact fertility on its own.


Hypothyroidism can also impact the luteal phase by disrupting its length, subsequently interfering with progesterone levels, a vital hormone to maintaining a pregnancy. Here is how progesterone is incredibly important for optimal fertility:


▫️Raises the basal body temperature, changes cervical fluid and cervical positioning

▫️Stops the ovaries from releasing any other eggs during the remainder of the pregnancy

▫️Causes the uterine lining to thicken and hold firmly to support a pregnancy

▫️Progesterone is heat producing and is mostly made by the corpus luteum. The corpus luteum produces the progesterone needed to support the pregnancy until the end of the first trimester when the Placenta takes over.


Moral of the story...all of your hormones are connected. This is why it is important to evaluate for thyroid hormone imbalances when focusing on preconception planning or during early pregnancy.

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