Written by Dr. Sanjana V.B Bhms,dbrm,cdn

Founder & medical director of siahmsr wellness.in

Reviewed by SIAHMSR

All rights reserved with siahmsr digital healthcare[siahmsr wellness]

How do thyroid diseases affect women's health?

Overview

   Thyroid hormonal disorders are more common in females especially in the reproductive age groups. Thyroid disorders in women include autoimmune thyroid diseases (AITD), thyroid goiter, nodule and cancer.

AITD mainly consist of autoimmune thyroiditis [Hashimoto’s thyroiditis] and Graves’ disease.

The female preponderance of thyroid diseases is closely linked to female hormones estrogen. Also, thyroid hormones have great action on a woman's reproductive system, particularly if the thyroid is overactive or underactive. Thyroid hormone dysfunctions and diseases play a crucial role in fertility, pregnancy & reproduction.

   The thyroid is a small, butterfly-shaped gland located at the base of the neck, just below the Adam's apple. The thyroid gland makes two main hormones: thyroxine (T-4) and triiodothyronine (T-3) and these hormones are vital for the proper functioning of the body and mind.

 The common characteristic of thyroid disorders is female preponderance in their prevalence. The female-to-male rate ratio is reported at 4~6:1 for AITD and about 3~4:1 for thyroid nodule. The effects of female sex hormones [estrogen & prolactin] and X chromosome inactivation on thyroid gland and immune system greatly contribute to the female predisposition for AITD. The direct actions of estrogen on the thyroid tissue contribute to the development of thyroid goiter, nodule and cancer in women.

The imbalance in thyroid hormone levels may have the following effects on a woman's body at different phases of life:

·  Impact  of thyroid dysfunctions on puberty

     Thyroid hormone is essential for the growth and maturation of many target tissues &organs, including the brain and skeleton in children from infancy to puberty. Thyroid hormonal insufficiencies affect growth adversely.

 Autoimmune thyroid diseases AITDs are common in adolescent female population. Autoimmune thyroid diseases (AITD) are defined by the lymphocytic infiltration of the thyroid. It also includes Graves’ disease & chronic lymphocytic thyroiditis or Hashimotto’s thyroiditis. Genetics and environmental factors play a pivotal role in the occurrence of AITDs.

Usually antibodies against thyroid antigens as thyroperoxidase (TPOAb), thyroglobulin (TgAb), and anti-TSH receptor (TRAb) are detectable in serum in chronic lymphotic thyroiditis [CLT] and Graves’ disease respectively.

Graves' disease:

 More than 95% of cases of hyperthyroidism in children and adolescents are due to Graves’ disease. The  incidence rates of thyrotoxicosis below 15 years of age has  increased in the last  few years. Graves’ disease has been recorded in pubertal children with other autoimmune diseases. The major clinical manifestations of Graves’ disease  in adolescents are :

Hyperthyroidism [ increased levels of T3,T4 and low or undetectable TSH] 

Goiter may or may not be present.

Ophthalmopathy or graves’ disease related eye problems in adolescent girls are usually mild. Eyelid retraction and “stare” look of eyes may be seen. Other signs are not commonly found.

Pretibial myxedema ,localized lesions of the skin resulting from the deposition of hyaluronic acid on pretibial area of leg is not generally found in pubertal age group.

 Acropachy [prominent irregular and spiculated periosteal new bone formation in the hands and feet detected on radiography or X-ray] is not detected commonly in children and adolescents.

Other symptoms of Graves' disease are:

Anxiety, irritability, weight loss, increased appetite, increased bowel movements, heat intolerance, increased sweating, fast heart beat ,insomnia or lack of sleep etc.

The care of children with Graves’ disease  requires physicians with expertise in this area. Treatment guidelines developed for adults cannot be simply applied to children.

Risk factors for Graves disease include:

Being female

Family history of Graves disease or other autoimmune conditions

Use of iodine or medicines that have iodine

Stress

Viral infections

History of smoking.

                                                  SIAHMSR                                       

Chronic lymphocytic thyroiditis (CLT)or  Hashimoto's thyroiditis 

 CLT is the most common cause of thyroid enlargement in children and adolescents in iodine sufficient areas, although it occurs in iodine deficient areas too.It is common in women also.

The common symptoms & signs of CLT are:

Weakness

Increased sensitivity to cold

Increased sleepiness

Dry skin

Constipation

Fatigue

Muscle aches, tenderness and stiffness

Joint pain and stiffness

Irregular or excessive menstrual bleeding

Depression

Difficulty with memory or concentration

Swelling(goiter)

A puffy face

Brittle nails

Hair loss

These are the range of symptoms of  this thyroid disorder. However ,all the symptoms may not be  present in every affected child or women. It depends on the stage  or duration of disease .Women with CLT may have following thyroid hormonal status:

Euthyroid[ normal thyroid function TSH,T3,T4 normal], or they may have subclinical[ only TSH elevated ,normal t3 & t4] or overt hypothyroidism [with low t3,t4 thyroid hormones, TSH elevated ]depending on the severity of the immunologic damage.

In clinical practice , the symptoms most commonly observed are depression and hair loss in adolescent age groups. Of late, many  adolescent male children also are affected with CLT or Hashimotto’s thyroiditis.

 Thyroid disorders especially CLT and Graves 'disease can cause puberty and menstruation to occur abnormally early or late. It can also affect the quantity of menstrual blood. Thyroid hormone imbalance can cause very light or very heavy, irregular menstrual periods or absence of menstruation.

Colloid goiter is the second most common cause of  thyroid enlargement in childhood after CLT.

As in adults, the most common form of thyroid cancer in childhood and adolescence is papillary thyroid carcinoma. Children exposed previously to thyroid irradiation are at high risk

·  Impact on reproductive age group

 Thyroid disorders may prevent ovulation in women of reproductive age group. Ovulation is the release of egg by the ovary in the mid part of 28 day menstrual cycle. Thyroid dysfunctions prevent ovulation process and eventually it enhances the risk for cyst development, especially in women having underactive thyroid (hypothyroidism).

 Severe hypothyroidism can actually cause milk production and discharge from the breast [ galactorrhea] while preventing ovulation. Thyroid dysfunction may cause infertility and miscarriage in women.

·  Impact on pregnancy, fetus &child birth

  Thyroid disorders occurring or persisting in mothers during pregnancy may affect the fetus badly. Thyroid hormone insufficiency, underactive thyroid or hypothyroid state in women can cause miscarriages, preterm delivery, and stillbirth. Therefore it is very crucial to bring your under active thyroid to normalcy through medications before you plan pregnancy. Sometimes hypothyroid state may cause excessive bleeding immediately after child birth [post-partum hemorrhage].

It may also lead to postpartum thyroiditis, a condition of thyroiditis persisting after child birth.

Severe morning sickness [hyperemesis gravidarum ]  may occur in women with overactive thyroid[hyperthyroidism].

Impact on fetus:

During the first trimester of pregnancy, fetal brain development is totally dependent on thyroid hormones of the mother. Thyroid hormonal insufficiency causes congenital hypothyroidism ,which is one of the major  causes of mental retardation  in infants.

 Hyperthyroidism in newborns is usually a transient consequence of transplacental [ through placental blood vessels] passage of TSH receptor stimulating antibodies from mother to foetus.

Hypothyroidism can be detected in infants born to hypothyroid mothers, due to trans placental passage of TSH receptor antibodies or hypothalamic-pituitary suppression.

·  Impact on women of menopausal age group

    Thyroid gland undergoes certain age related changes with growing years. Thyroid epithelium undergoes degenerative processes that lead to its flattening; the size of thyroid follicles diminishes, while fibrous connective tissue and lymphoid tissue proliferates. In consequence, the size of the thyroid gland may reduce over time.

The ability of the thyroid gland to uptake iodine diminishes. Hormonal production also is affected with ageing. The daily production of the main thyroid hormone T4 decreases per 20 µg, & at the same time its metabolism slows down due to the reduced activity of 5’ deiodinase-I. The daily production of T3 decreases per 10 µg in women, and the serum concentration of T3 in elderly people decreases significantly.

    Research studies show that serum TSH concentration is probably age-dependent and  serum TSH concentrations rise with age in both men and women. The interpretation of thyroid function tests (TFTs) may be complicated in the ageing population, and especially the diagnosis of subclinical hypothyroidism should be made with caution.

Subclinical hypothyroidism is defined as a normal serum free thyroxine (T4) concentration in the presence of an elevated serum thyroid-stimulating hormone (TSH) concentration.The incidence of elevated TSH is about 7.6% in the general female population but rises to 17% in women over 70 years of age.

The progression of subclinical to overt hypothyroidism is about 2.6% per year and can double in cases with anti-TPOantibody positivity in autoimmune thyroiditis  or if TSH > 10 mIU/l.

An additional risk for elevated TSH level in old people is posed by the various medications used , which can influence the thyroid function tests.TFT.

For example metformin and glycocorticosteroids for treating diabetes for a prolonged period of time, may decrease serum TSH concentration. Amiodarone, the drug used for regulating the rhythm of heart, has a multidirectional effect on serum TSH and thyroid hormone levels.

 Thyroid disorders may cause premature menopause (before age 40 or in the early 40s). Hypothyroidism [underactive thyroid], nodular goitre, and cancer are highest among postmenopausal and elderly women.

How does hyperthyroid state affect elderly women?

Some symptoms of overactive thyroid (hyperthyroidism) may also present like early menopause. These include lack of menstruation, hot flushes, inability to sleep (insomnia), and mood swings. The symptoms can be nonspecific or common with menopausal and ageing complaints.  If you are in early forties and experience these symptoms, it is recommended that you check your thyroid function. You can understand your thyroid hormonal status  simply by doing the thyroid function test [TFT].

The thyroid function test, includes TSH, T3, T4 hormones level in blood. If the thyroid hormones t3, t4 or either one of them is high with your TSH normal, or low you should consult a doctor. You might be suffering from overactive thyroid or hyperthyroidism. Unrecognized thyroid hormonal  dysfunction  may lead to increased risk of cardiovascular diseases like heart attacks, strokes etc. Other over active or under active thyroid related issues are bone fractures, memory related problems, cognitive impairment and depression.

What are the complications of thyroid dysfunctions in women?

Thyroid dysfunction if left untreated it may increase the death rate from heart failure, cardiac arrhythmias and fibrillation.

 Therapy for thyroid dysfunctions is different in postmenopausal and elderly women than in young people; in elderly women underactive thyroid [hypothyroid] should be treated with caution, because high doses of L-thyroxine supplementation can lead to cardiac arrhythmias and increased bone turnover and bone fractures with drug induced [iatrogenic] hyperthyroidism. Therefore some degree of caution is needed ,pertaining to the doses of L-thyroxine treatment for underactive thyroid.

In menopausal age group hyperthyroidism should be preferentially treated with radioiodine.

Nowadays thyroid nodules and cancers are common in women over 50 years old; the diagnosis and treatment methods are not different from that of young groups. However, the prognosis or outcome of cancer treatment and surgery is not so good in postmenopausal women.

written by dr.sanjana vb[ copyright]

References:

1.   https://pubmed.ncbi.nlm.nih.gov/25668600/

2.   https://www.hopkinsmedicine.org/health/conditions-and-diseases/thyroid-disorders-in-women#:~:text=Thyroid%20disorders%20can%20cause%20puberty,(a%20condition%20called%20amenorrhea).

3.   https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5509968/

4.   https://www.ncbi.nlm.nih.gov/books/NBK279032/

5.   https://emedicine.medscape.com/article/1103765-overview

6.   https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3608006/