✓ Hashimoto's Thyroiditis and Infertility: What's the Link?

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When the desired pregnancy doesn't come, it could be the "fault" of the thyroid: the butterfly-shaped gland at the base of the neck, just above the collarbone. That's right, because thyroid disorders, including the Hashimoto's thyroiditis, they can cause infertility more often than you might think! Hashimoto's syndrome is one chronic thyroid disease which can cause hypothyroidism or, more rarely, hyperthyroidism. If left untreated, this condition can reduce the chances of getting pregnant and cause serious complications in a pregnancy.

Let's see everything there is to know about Hashimoto's thyroiditis and its link with female fertility.

What is Hashimoto's Thyroiditis

La Hashimoto's thyroiditis o chronic autoimmune thyroiditis, described for the first time by the specialist Hakaru Hashimoto in 1912, is one of the most common and frequent thyroid diseases. In fact, it is estimated that it affects about 5-15% of women, causing, when left untreated, irregular menstrual cycles and anovulatory cycles, thus interfering with fertility. In Hashimoto's thyroiditis, the defect is in the immune system which no longer recognizes the thyroid as part of the body and attacks it, producing antibodies against this organ. The direct consequence is that the thyroid gland becomes inflamed and its ability to produce hormones is impaired.

Read also: How to prevent thyroid disorders

What are the causes of Hashimoto's thyroiditis

Hashimoto's thyroiditis it mainly affects women and its causes are to be found in a genetic predisposition to the disease. Patients with some particular autoimmune diseases such as:

celiac disease;
diabetes;
vitiligo.

Also, Hashimoto's thyroiditis occurs more frequently in people with genetic diseases such as Down syndrome, Turner syndrome and Klinefelter syndrome.

The most common symptoms

By itself, Hashimoto's thyroiditis does not cause symptoms, at least at an early stage. Later, however, it can appear primary hypothyroidism which brings with it symptoms such as:

apathy;
tiredness;
weight gain;
hair loss;
difficulty in concentration;
water retention
constipation.

The disease can also lead to more serious manifestations as:

menstrual disturbances, with irregular and / or abundant menstruation;
difficulty getting pregnant, due to menstrual irregularity or anovulatory cycles;
problems during pregnancy related to the development of the fetus; and an increased risk of miscarriage.

However, hypothyroidism is not always present and in some cases it can even present itself without any symptoms.

Rarer, however, is thehyperthyroidism linked to Hashimoto's thyroiditis. Hyperthyroidism can cause:

nervousness;
excessive sweating;
tremors;
anxiety;
weight loss;
tachycardia.

In both cases it is important to diagnose the disorder as soon as possible and thus initiate the right treatment.

Read also: World Thyroid Week: how we are put in iodine supply

How is Hashimoto's thyroiditis diagnosed

Let's start by saying that the diagnosis of Hashimoto's thyroiditis is not at all simple and several tests may be necessary, as also indicated by the new guidelines of the American Thyroid Association published in 2022. The first step that the doctor will take will be to retrace the history clinic of the patient and her family with a accurate medical history, which will be followed by a physical examination to evaluate the presence of nodules or swelling of the thyroid gland.

It will then be necessary to perform other checks such as:

BLOOD ANALYSIS: the guidelines suggest proceeding with the search for antibodies to the thyroid gland, in particular, the presence of antibodies against thyroperoxidase (TPO) and anti-Thyroglobulin (TG), main factors for the diagnosis of Hashimoto's thyroiditis. Thyroid hormones (T3, T4 and TSH) are also measured to evaluate thyroid function and hypothyroidism. Thyroid stimulating hormone (TSH) is the best indicator of how your thyroid is working. Since its task is precisely to stimulate the thyroid, the presence in the blood will be:

high, in cases of hypothyroidism;
low, in cases of hyperthyroidism.

ULTRASOUND: to evaluate the morphology and volume of the thyroid, as well as to verify the presence of thyroid nodules, typical of Hashimoto's thyroiditis.

What to do in case of Hashimoto's thyroiditis

Hashimoto's thyroiditis generally does not require treatment. However, it becomes necessary to intervene with one hormone replacement therapy based on levothyroxine when thyroiditis leads to hypothyroidism.

Hypothyroidism is a pathology that slows down the functioning of the thyroid gland due to a low presence of thyroid hormones. It is a condition that should not be underestimated because if left untreated it can lead to alterations in the menstrual cycle, a greater risk of miscarriage (poly-abortion), anxiety, depression, heart problems and even a slowdown in mental functions.

Read also: Female infertility, when the problem is the thyroid

Hashimoto and infertility

Hashimoto's thyroiditis can cause the thyroid to be less active than usual: in these cases we speak of hypothyroidism. If hypothyroidism occurs it is very important restore normal hormone levels because low thyroid hormone levels can affect many aspects of the menstrual cycle and ovulation.

The consequences are:

anovulatory cycles;
irregular release of the egg;
low basal body temperature;
reduction of the possibility of implantation of the embryo.

All conditions that can interfere with fertility e therefore make conception difficult. This is why, according to a recent study, it would be advisable to perform a thyroid function assessment in all women seeking medical advice for infertility.

Furthermore, it would always be advisable to check the thyroid function of all women who wish to become pregnant. Fortunately, more and more gynecologists decide to check the thyroid function of their patients in the pre-conception phase, the best strategy to avoid possible damage to the fetus in case of untreated hypothyroidism.

Also read: Thyroid tests before getting pregnant

Hashimoto and pregnancy

Women who are trying to get pregnant and have Hashimoto's thyroiditis should tell their doctor who will advise them to perform the thyroid hormone test. Undiagnosed hypothyroidism during gestation can be potentially very dangerous for the woman, but also and especially for her baby.

As the Del Paesena Society of Endocrinology recalls, hypotoroidism is a condition associated with an increased risk of:

miscarriage;
preterm birth;
low birth weight;
stress and fetal death;
maternal hypertension;
postpartum hemorrhage;
anemia materna.

In addition to other risks related to the development of the fetus.

In fact, during the first trimester of pregnancy, the future mother, with her own thyroid hormones, provides the fetus with all the thyroid hormone it needs. So if a woman is low on thyroid hormone, her baby too can suffer from hormone deficiency at a very critical time when brain development is underway. This can have a negative impact on the mental development of child.

If hypothyroidism is diagnosed right before pregnancy, it is good that treatment is started and they are restored normal hormonal values before trying to have a baby. In any case, hypothyroidism due to Hashimoto's thyroiditis does not represent a contraindication to pregnancy. It will be enough simply to follow the right treatment, which is generally the same one that was followed before conception. Thyroiditis can be kept under control without causing risk to mom and her little one.

Sources used:

Higher Institute of Health, thyroiditis;
Del Paesena Society of Gynecology and Obstetrics, Thyroid and Pregnancy, National reference guidelines;
Del Paesena Society of Endocrinology, Hypothyroidism and Pregnancy;
Impact of thyroid disease on fertility and assisted conception, Clinical Endocrinology and Metabolism, 2022;
American Thyroid Association, Guidelines for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum, 2022

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