How Birth Control Effects Thyroid Disease

Women are the majority of people who are affected by thyroid disease. Most of these women are of childbearing age or are perimenopausal/menopausal. This means while being treated for thyroid disease, some are taking medication such as birth control or hormone replacement pills.

It’s important for women who are taking thyroid hormone replacement to understand the effects of medication that containing estrogen can have on your thyroid treatment.  Women should also be aware if they are taking hormone replacement medication for their thyroid condition after being on birth control that contained estrogen.

The Effects of Estrogen on the Thyroid

Those that are struggling with infertility, PMS, mood swings, weight gain, or low libido, may have a hormone imbalance. There are many symptoms linked to having too much estrogen.  It can cause thyroid dysfunction, an autoimmune condition, cancer, and more.

When there is an increase in estrogen it can be a sign of pregnancy, genetic predispositions, and the use of medication such as birth control or hormone replacement.

When your estrogen levels are increased it increases the levels of your thyroxine-binding globulin, know as TGB. TGB is the protein known as the “globulin.” It plays a special role in two thyroid hormones, T4 and  T3. When TBG is high, it causes more thyroid hormone and lowers the amount of free thyroid hormone in the body. This can lead to an increase in TSH levels, which then affects your T4 and T3 levels.  Those that are hypothyroid see the most changes in symptoms when taking estrogen.

When Estrogen Becomes a Problem

We all produce estrogen in the adrenal glands and store it in our fat tissue, as well as the ovaries in women and testes in men. Estrogen is important for childbearing, keeping cholesterol levels in range, and protecting bone health. When your levels are not balanced other hormones are affected causing many health issues.

Symptoms of Estrogen Dominance


Weight gain, mainly in the hips, waist, and thighs
Menstrual problems such as light or heavy bleeding
Fibrocystic breasts
Uterine fibroids
Loss of sex drive
Depression or anxiety

Through three different paths, estrogen is broken down in the liver.  Estrogen will be converted into good or bad metabolites, depending on the path.

Health Risks

Hormonal Cancers

The biggest risk associated with estrogen dominance is cancers. Breast cancer in both men and women, uterine and ovarian cancers in women, and prostate cancer in men can be caused by hormones associated with stored fat.  Stored fat produces a stronger form of estrogen called estradiol. The estradiol hormone is the far more harmful form of estrogen because it is more difficult to detoxify.

Estradiol, the most potent form of estrogen is produced in stored fat. Hormonal cancers are associated with stored fat. This type of harmful estrogen is more difficult for your body to detoxify, leading to more circulating estrogen and “bad” estrogen metabolites.

Autoimmune Disease

High estrogen levels have known to enhance the inflammatory response in our immune system. This causes the antibodies to increase and continue the attack on the body’s own tissues. It has shown that it’s the unstable fluctuations around childbirth and menopause the contribute to autoimmune diseases such as Hashimoto’s.

What To Do Next?

Recheck Thyroid Function After Starting and Stopping Birth Control or Hormone Replacement
Most women that are on birth control don’t experience many symptoms in thyroid function while on birth control or hormone replacement with estrogen. However, research has shown that if you’re taking thyroid replacement medication and add estrogen medication,  T4 will decrease. This is especially important for those that have hypothyroidism symptoms such as extreme fatigue, brain fog, and weight loss.

These symptoms can return and worsen causing doctors to increase their thyroid medication. This is also unsafe for those that survived thyroid cancer and need to keep thyroid hormones regulated. If you are starting or stopping birth control or thyroid replacement hormone be sure to check your thyroid every three months.