The role of all glands in the human body is to secrete, that is, release, hormones into the blood stream. These hormones are chemical messengers that cause changes in the body. The thyroid is one such gland. It is located in front of the trachea (wind pipe) in the neck and is shaped rather like a butterfly. The hormone it secretes, thyroxine, has numerous effects throughout the body including regulating heart rate which ties in to its, perhaps, most widely known action the modulation of the rate at which the body uses and stores energy from food – generally referred to as the metabolism.

The whole body is affected if the production of thyroxine is out of step with its needs. Over production of the hormone by an over active thyroid gland is called hyperthyroidism. The symptoms of this condition include weight loss (without dietary modification), inability to gain weight with additional calories, anxiety and agitation, tremor, lighter and /or shorter menstrual periods or amenorrhoea (periods stopping all together), excessive perspiration, insomnia, muscle weakness, fatigue and rapid heartbeat. People with an over active thyroid often report an unusual sensitivity to heat.

Younger women are more likely to be diagnosed with an over active thyroid gland than those over the age of thirty. As the condition can lead to fewer, shorter and lighter periods or them ceasing completely women with hyperthyroidism can have great difficulties conceiving. Women with an over active thyroid gland are also at greater risk of miscarriage. The anxiety and agitation that are key symptoms in the condition can be attributed to the natural feelings of uncertainty and nervousness associated with being pregnant. It is important, especially if you have a family history of thyroid hormone imbalance that your thyroid function is checked.

Women with pre-existing hyperthyroidism who are planning to conceive should ensure the condition is well managed and that, if this is done using anti-thyroid medication a possible change to a variant that is safe for use during pregnancy, such as propylthiouracil (PTU), may be recommended. Although PTU is widely considered to be the safest of this type of medicine for pregnant women to take, it can affect the baby’s thyroid gland. Women with hyperthyroidism need to be monitored closely and have regular blood tests throughout pregnancy.

Some women cannot take PTU leaving few other drugs to control their thyroid hormone imbalance that would be safe during pregnancy. In such instances a thyroidectomy, that is, surgical removal of the thyroid gland may be recommended before becoming pregnant or during pregnancy. A further option is treatment with radio-active iodine. This is not, however, a treatment that can be carried out during pregnancy due to unacceptable risk to the foetus.

Just as is in the case of an over active thyroid, key symptoms of an under active thyroid are easily mistaken for normal or common features of pregnancy such as fatigue, weight gain and easily becoming overly emotional. It is well worth getting your thyroid function tested if you are planning to become pregnant, especially if you have a family history that included thyroid gland issues. Treating an under active thyroid gland during pregnancy is rather more straight forward that treating hyperthyroidism. The drug used to correct the deficit of thyroid hormone, levothyroxine, is exceptionally similar to the natural hormone produced by the gland itself and is safe to take during pregnancy.

Women with pre-existing hypothyroidism may need to, in consultation with their physician, increase the dose of levothyroxine they take during pregnancy. Blood tests to establish the correct dosage should be taken at regular intervals during pregnancy and if symptoms linked with having an under active thyroid worsen or new symptoms appear.

Around one in twenty women who have recently had a baby will develop a thyroid problem, usually inflammation of the thyroid gland. Once again, symptoms of this problem, post partum thyroiditis can masquerade as symptoms of other conditions, most commonly post natal depression. The symptoms a woman will experience will depend on whether or not her thyroid gland becomes over active or under active and are the same as women with pre-existing hyperthyroidism or hypothyroidism experience. Usually, it is only the most extreme cases of post partum thyroiditis that require treatment or those that do not resolve themselves within around four months after birth.

If a woman has experienced thyroid gland problems during her pregnancy or has a pre-existing thyroid condition then the baby’s thyroid function will need to be tested shortly after birth. This is done via a blood test. This is essential to ensure the child can utilise the calories and nutrients in his or her feeds. Babies with thyroid conditions fail to thrive and it is, therefore, absolutely vital for the child’s health any problem be detected at the earliest possible opportunity.