The thyroid gland, found at the front of the neck, produces thyroid hormone. This hormone is responsible for a vast range of processes in your body and, most specifically, your metabolism. You can have too little or too much thyroid hormone, and we know that thyroid problems are more common in women than men, and are often triggered by pregnancy and menopause. It stands to reason that your thyroid and periods are connected too. Here we look into this in more detail.

Period problems

There are a variety of problems that women can experience with their periods and menstrual cycle. Periods may be irregular, heavy, or absent. They are a number of different causes including hormonal contraception, perimenopause, extreme weight changes, exercise or stress and medical conditions like polycystic ovary syndrome (PCOS). Having problems with your thyroid is another cause of irregular periods.

For some women, irregular periods are very normal and they’ve never been regular since puberty. However, if your periods become irregular under the age of 45, or your periods are very frequent or very infrequent, it’s worth talking to your GP.

Hypothyroidism

Hypothyroidism is the most common thyroid problem that causes problems with your menstrual cycle. Hypothyroidism is a condition where your thyroid gland doesn’t produce enough thyroid hormones. Prevalence rates for hypothyroidism vary by region, but around 5% of the global population is believed to have hypothyroidism. It notably affects more women than men.

The thyroid is crucial for your metabolism. Metabolism, in a nutshell, is how fast or slow processes happen in your body. With hypothyroidism, many bodily processes slow down. The result is symptoms such as fatigue and lethargy, feeling cold, joint pain, depression, unexplained weight gain, constipation, dry skin and more. It’s no surprise, therefore, that it can also affect your periods.

What happens to your period with hypothyroidism?

It’s quite a complex process to understand what happens when hypothyroidism is affecting your menstrual cycle. It’s best understood as a cascade of problems, triggered by too little thyroid hormone triggering various other hormonal changes.

As your thyroid levels decrease, the hypothalamus and pituitary glands both get the signal to try and increase more thyroid hormone production. They release more thyrotropin releasing hormone (TRH), thyroid stimulating hormone (TSH) and prolactin. The cascade continues with prolactin suppressing another hormone called gonadotropin-releasing hormone (GnRH). GnRH is needed to stimulate the production of luteinizing hormone and follicle-stimulating hormone which are critical for helping your ovaries to work optimally. The result is irregular periods.

If hypothyroidism slows down ovulation then this can cause heavy periods. The growth and shedding of the uterus becomes disordered and the result can be unpredictable cycles and heavy bleeding. At the same time, your coagulation factors (how your blood clots) may also be affected, also increasing your risk of heavy bleeding. However, increased prolactin can also thin the lining of the uterus and this can stop you having periods altogether.

Thyroid and periods – can medication help?

Menstrual problems may be one of the first indications that you have got hypothyroidism. The good news is that with the right thyroid medication, most likely levothyroxine, your periods can become more regular and manageable again. It can take some time to balance your thyroid medication, and may require a number of blood tests, but you should be able to improve your symptoms over time.

Remember, there are other causes of heavy and irregular periods. Your doctor may want to check for other problems, including fibroids and polyps, as well as signs of polycystic ovary syndrome (PCOS).

Will my thyroid problems affect my fertility?

Because hypothyroidism disrupts your menstrual cycle, it can be harder to get pregnant. There are a few reasons for this.

First, if your periods are irregular then it is much harder to predict ovulation and fertile times. As such, if you are trying to conceive then you should be having sex every 2-3 days throughout your cycle.

Secondly, conception requires both ovulation and a healthy endometrial lining, allowing the embryo a good place to implant. Ovulation can be disrupted by hypothyroidism. In addition, it’s not uncommon with hypothyroidism to have a short luteal phase. The luteal phase is the time between when you ovulate and when the uterine lining is shed, with your period. When this phase is short, it can be very difficult for an embryo to implant. This is because it takes several days between conception and when the embryo is ready for implantation.

There is also evidence that when hypothyroidism is untreated, the risk of miscarriage is also increased.

Be aware that disrupted menstrual cycles and problems with fertility can actually be caused by borderline thyroid problems, so it is worth fully investigating all possible causes.

What treatment will help my periods?

If hypothyroidism lies behind your irregular or heavy periods, or infertility, then treatment can help. Levothyroxine is a prescribed medication which gives you replacement thyroid hormones which your body isn’t producing. Levothyroxine is a synthetic option. There are also natural thyroid medications such as Armour Thyroid and NP Thyroid.

When your body gets enough thyroid hormone once more, the cascade of disruption stops and processes return to normal. This will mean your reproductive function will return to normal and stabilize too.

Can hyperthyroidism affect my periods?

Hypothyroidism is when you have too little thyroid hormone. The opposite is called hyperthyroidism and this is when you have too much thyroid hormone. This can cause absent or infrequent periods and decreased fertility because ovulation is prevented. This too can be treated.

Summary

Your thyroid and its health affect your periods. This can be seen with hypothyroidism through heavy and irregular periods, and with hyperthyroidism through light, irregular or absent cycles. This happens because the thyroid hormone is so important for producing the hormones needed for a regular and ordered menstrual cycle. As a result, thyroid difficulties can also affect fertility and pregnancy, making it harder to get pregnant and carry a healthy pregnancy.

Thyroid problems can be successfully treated, reducing and removing their impact on your periods.

Remember that the information given here from International Pharmacy is guidance only. If you think thyroid problems may be the cause of your period problems, always speak to your doctor in the first instance.