Can Taking Levothyroxine Affect the Use of Birth Control Pills?

Is it appropriate to take a pre-exposure prophylaxis (PrEP) pill while on 50 micrograms of Entacapone?

I have Hashimoto's thyroiditis and hypothyroidism, and I have been regularly taking Levothyroxine 50 micrograms.
However, due to irregular menstruation, I am considering adjusting my menstrual cycle with oral contraceptives.
I would like to know if it is safe to take birth control pills.
Will the contraceptives have any effect on my thyroid medication? Thank you.

0412, 20~29 year old female. Ask Date: 2020/10/19

Dr. Li Jian reply Internal Medicine

Emergency contraceptive pills and thyroid hormones do not produce serious or major interactions; however, regular monitoring of thyroid function is still recommended.

Reply Date: 2020/10/19

More Info

Taking Levothyroxine, a synthetic form of the thyroid hormone used to treat hypothyroidism, does not typically interfere with the effectiveness of birth control pills. However, there are several important considerations to keep in mind, especially for individuals with Hashimoto's thyroiditis and hypothyroidism.

First, it is essential to understand how both medications work. Levothyroxine is prescribed to normalize thyroid hormone levels in the body, which is crucial for maintaining metabolism, energy levels, and overall health. Birth control pills, on the other hand, contain hormones (estrogen and progestin) that prevent ovulation and regulate menstrual cycles.
In general, studies have shown that hormonal contraceptives do not significantly affect the absorption or metabolism of Levothyroxine. However, some research suggests that estrogen-containing contraceptives can increase the levels of thyroid-binding globulin (TBG) in the blood, which may lead to an increase in the total thyroid hormone levels measured in blood tests. This does not necessarily mean that the effectiveness of Levothyroxine is diminished, but it may require your healthcare provider to monitor your thyroid hormone levels more closely and adjust your Levothyroxine dosage if necessary.

For women with Hashimoto's thyroiditis, it is crucial to maintain stable thyroid hormone levels, as fluctuations can lead to symptoms such as fatigue, weight gain, and mood changes. If you decide to start taking birth control pills, it is advisable to have regular follow-ups with your healthcare provider to monitor your thyroid function tests. This will help ensure that your Levothyroxine dosage remains appropriate and that you are managing both your thyroid condition and reproductive health effectively.

Additionally, it is important to consider the potential side effects of hormonal contraceptives, which can include nausea, headaches, mood changes, and, in rare cases, an increased risk of blood clots. If you have any risk factors for cardiovascular issues, such as a history of blood clots or smoking, you should discuss these with your healthcare provider before starting birth control pills.

In conclusion, taking Levothyroxine should not negatively impact the use of birth control pills, but it is essential to maintain regular communication with your healthcare provider. They can help monitor your thyroid levels and adjust your medication as needed to ensure both your thyroid health and reproductive health are optimized. Always consult with your healthcare provider before making any changes to your medication regimen or starting new medications.

Similar Q&A

Can Low TSH Levels Affect Birth Control Pill Use?

Hello Doctor, I previously had a habit of taking emergency contraceptive pills. After stopping the medication last month, my menstruation has not arrived. After consulting with a gynecologist, I was informed that I have a 4 cm cyst and that I should be monitored in three months. ...

Dr. Yuan Tianmin reply Breast and Thyroid
An occasional blood test does not necessarily indicate the possibility of hyperthyroidism. It may require repeated blood tests, especially if you are taking certain medications, and you may need to wait for additional data to determine whether hyperthyroidism is truly present.

Can You Use Birth Control Pills While Treating Hyperthyroidism?

Hello doctor, I am currently being treated for hyperthyroidism and I am taking MERCAZOLE 5 manufactured by both domestic and foreign pharmaceutical companies. My condition has stabilized. Is it safe for me to take the contraceptive pill named Alesse? Thank you.

Dr. Zhang Kunmin reply Obstetrics and Gynecology
Hello, the following medications can indeed affect the efficacy of birth control pills: 1. Antibiotics (Penicillin, Cephalosporins, Erythromycin, Sulfonamides, Bactrim, Chloramphenicol) - may reduce the gut flora that aids in absorption, thereby decreasing the effectiveness of ...

Impact of Birth Control Pills on Cholesterol Levels: What You Need to Know

Dear Director: I have been taking oral contraceptives and menstrual regulation medication for about three months. Recently, my blood test results showed elevated total cholesterol levels. The total cholesterol is 385 mg/dL, low-density lipoprotein (LDL) cholesterol is 296 mg/dL, ...

Dr. Cao Guotao reply Obstetrics and Gynecology
Hello, the two are not closely related, and you can continue taking the contraceptive pill. Wishing you good health.

Impact of Thyroid Medication Adjustment on Ovulatory Bleeding: What to Know

Hello, doctor. I would like to ask if adjustments to medication for hyperthyroidism can affect ovulation bleeding. I am currently taking Methimazole, and on the day I followed the doctor's advice to reduce the dosage by half, I happened to experience ovulation bleeding. In t...

Dr. Zhang Kunmin reply Obstetrics and Gynecology
Hello, the factors affecting intermenstrual bleeding are numerous, including age, environment, lifestyle, stress, emotional instability, weight changes, medications, emergency contraceptive pills, diet, polycystic ovary syndrome, lesions of the uterus or cervix, infections, ovula...