We did a previous post on how our thyroid health impacts miscarriage and specifically dug into iodine. If you haven’t read that blog post yet you can read it here. In this post we want to do more of an overview of the different ways our thyroid health can impact our fertility and chances of miscarriage. Here are the topics we will cover:
One of the main ways our thyroid can impact our ability to maintain a healthy pregnancy is by how it impacts progesterone levels. Thyroid hormone impacts our hypothalamus, which is what is responsible for releasing gonadotropin-releasing hormone (GnRH). This talks to the pituitary gland, which then releases FSH to stimulate follicles in the ovaries. Our follicles then release estrogen so that FSH goes down. The dominant follicle is then selected and egg development starts. A peak of estrogen causes the egg to mature and we get a surge of LH and FSH, which stimulates ovulation. The dominant follicle releases the egg, LH and FSH go down. The follicle then becomes the corpus luteum and causes progesterone to peak. Without adequate thyroid hormone, the communication from the brain to the ovaries may not occur and ovulation can be delayed or not happen at all. No ovulation = low progesterone levels. Low progesterone is a major contributor to miscarriage.
Thyroid hormones (T3 and T4) impact how sensitive the cells in the uterus are to estrogen. If the cells in the uterus aren’t able to utilize estrogen effectively, it can negatively impact cell proliferation and the development of a healthy uterine lining. This often leads to a thick uterine lining, which can make the chances of pregnancy lower. Having too much thyroid hormone can lead to a thin uterine lining, which increases the risk of miscarriage.
Our thyroid sets the metabolic pace of the body, which has a big impact on our ability to make digestive juices. If we cannot breakdown our food well, this will lead to negative changes in our gut microbiome as well as immune system function overtime. Gut and immune issues typically start with poor digestion. The precursor to poor digestion is often stress and thyroid dysfunction. This is why we can’t address gut and immune issues without looking into our thyroid function.
Thyroid health also greatly impacts egg quality because of how it impacts the development of follicles within the ovary. Remember back to the beginning when we talked about how thyroid hormone leads to the release of GnRH and FSH and LH? Without adequate thyroid hormone, we get poor follicle development, which can lead to decreased egg quality. Both underactive and overactive thyroid can lead to these issues. This can lead to low AMH levels as well.
Thyroid health also greatly impacts men’s health and specifically sperm quality. Poor thyroid function can lead to low testosterone levels, which greatly impacts sperm quality and motility. Just like with women, thyroid issues can also lead to digestive health issues and inflammation in men. Gut health and inflammation are major driving factors in poor sperm quality and low testosterone. Gut health is one of the first places we look when there is a sperm quality concern, which includes making sure thyroid is in a good place.
Egg and sperm quality matter because poor quality often leads to a higher risk of chromosomal abnormalities, which increases the risk of miscarriage (and makes conception harder to begin with).
Want to learn more about your thyroid? Here is a great mini thyroid course that will help you dig deeper.
reminder: i’m currently accepting people into my Nurture Your Fertility program. you can learn more here about the program and fill out an application!
