Thyroid Dysfunction and Women

The thyroid gland, an endocrine gland present in the neck, produces two hormones: 20% of tri-iodothyronine (T3) and 80% of thyroxine (T4). Thyroid is often the suspect when you lose or gain unexpectedly. Thyroid is the body’s thermostat; the hormones it secretes control metabolism and organ function, directly affecting weight loss or gain, energy levels, skin condition, heart rate, cholesterol levels, menstrual regularity and memory as well as other functions. T3 is the active version of thyroid hormone that drives cell metabolism and is responsible for fat-burning. Most of T3 is produced by converting T4 to T3 in the liver and kidneys. Without this conversion, the cells have too little T3 to maintain normal metabolism.

The thyroid gland doesn’t work in isolation. Thyroid function influences, and is influenced by, the pituitary, adrenals, parathyroid, and sex glands, all of which work together. Thyroid hormone production is controlled by hormones secreted by the pituitary and the hypothalamus. If the thyroid is underactive, the hypothalamus and pituitary gland can sense this and kick things back to normal. TRH (thyroid-releasing hormone), produced by the hypothalamus, prompts the pituitary to release TSH (thyroid-stimulating hormone) in your body, which in turn stimulates the thyroid to do its job and is responsible for the conversion of T4 to T3.

More women than men suffer due to thyroid dysfunction. Thyroid disorders can cause abnormally early or late onset of puberty and menstruation. Women with menstrual migraine headaches are often hypothyroid. Women in developed countries have too much estrogen, which creates hypothyroid symptoms. Excess estrogen impedes the cellular utilization of thyroid hormone. Many women experience underactive or hypothyroid issues during perimenopause and pregnancy.

 
Thyroid hormones interact with your body’s other hormones, such as estrogen and progesterone and influence their secretion. Low thyroid levels can interfere with ovulation. During pregnancy, human chorionic gonadotropin (hCG), an hormone produced by the the developing embryo increase thyroid hormone levels in the blood, which in turn affect the estrogen levels. In fact, throughout the reproductive life and the regular menstrual cycles, estrogen and progesterone levels as well as the thyroid hormone levels fluctuate (that is natural, of course). An underlying malfunctioning thyroid can get worsened during pregnancy and constant monitoring of optimum thyroid hormone levels would be needed to ensure the health of the baby.

Pregnancy and Thyroid

Often, thyroid problems give rise to symptoms that closely resemble those caused by menstrual disorders. Women with thyroid problems may find it difficult to become pregnant. Even if they did get pregnant, there are likely to be problems; it’s best to resolve all the issues before planning to have a baby. Under hypothyroidic conditions, the pituitary releases more of the hormone prolactin. Elevations of prolactin can interfere with ovulation. Low levels of thyroid hormone thus interfere with the rate at which your body metabolizes sex hormones, which can cause ovulatory disorders.

Thyroid problems are most common in middle aged women, a time when they face fluctuating hormone levels, and the symptoms from a malfunctioning thyroid can get masked, making its detection a little difficult. Sometimes hypothyroidic conditions may cause a woman to miss her period and experience nausea, and this condition be mistakenly attributed to pregnancy. And if pregnancy has actually occurred, the baby may be underweight, anaemic, and be even stillborn. Women with low thyroid hormone levels are at risk of giving birth to children who have developmental delays and lower scores on IQ tests. Women who are known to have hypothyroidism before they become pregnant also need to increase the dosage of thyroid hormones used to treat the condition. The doctor would have to monitor the hormone levels throughout the pregnancy.

The diet of a pregnant woman should be rich in iodine, which the thyroid gland uses to make thyroid hormone. Thyroid hormone is critical to normal development of the baby’s brain and nervous system. During the first trimester, the baby gets its supply of thyroid hormone through the placenta, after which its own thyroid begins to function.

Hyperthyroidism is the opposite of hypothyroidism and occurs when the thyroid gland is overactive and produces much higher levels of thyroxine than usual. Apart from causing restlessness, palpitations, loss of weight, etc., hyperthyroidism can affect menstrual periods, making them irregular, lighter, or disappear altogether. Similar to a hypothyroid woman, a hyperthyroid woman might find it difficult to conceive and is likely to have miscarriages.  Women who have untreated hyperthyroidism have a greatly increased risk of developing osteoporosis (brittle bones). Hyperthyroidism can also cause serious complications in pregnancy, including an increased risk of miscarriage, stillbirth, a low birth weight baby, abnormalities, early birth and pre-eclampsia.

Thyroid Problems After Pregnancy

Women with Type 1 diabetes have a much higher risk of developing thyroid problems after birth. The symptoms can be wrongly attributed to post-natal depression. It is important that women who have had postpartum thyroid disease be monitored carefully.

Causes of Thyroid Problems

The thyroid  is vulnerable to toxins in our environment. Industrial chemicals, pesticides and antibacterial chemicals in cosmetics contain estrogen-mimicking chemicals called xeno-estrogens which can disrupt women’s endocrine systems because of the large numbers of estrogen receptors in our bodies.

Another cause for thyroid problems is the autoimmune response of the bodies where it produces antibodies that attack the thyroid gland and cause Hashimoto thyroiditis (an autoimmune hypothyroidism) or Graves disease (over-activity of the thyroid).

Many people with type 1 diabetes have low thyroid hormones, as they both share the same cause — an autoimmune reaction.  Women with anti-thyroid antibodies may be at greater risk for miscarriage. The insulin resistance caused by diabetes interferes with follicular development and ovulation.

Women who are under constant stress, who have iodine or selenium deficiency or have severely restricted diet that causes eating disorders like anorexia and those who have taken chemotherapy or radioactive iodine treatment can suffer from hypothyroidism.

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