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Thyroid stimulating hormone (TSH)

The Thyroid Stimulating Hormone (TSH), or thyrotropin, is an important pregnancy hormone that is responsible for the stimulation of your thyroid gland. It is produced in your pituitary gland and its levels during pregnancy depend on the levels of hCG and estrogen in your blood. TSH levels are highest during the first trimester of your pregnancy and steadily decline over trimesters two and three.

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TSH is responsible for the release of thyroxine and other thyroid hormones from your thyroid gland, all of which are essential for the maintenance of your metabolism and the development of your baby’s brain. If you have high or low TSH levels you and your baby are at risk for: low birth weight, miscarriage and premature birth.

What does TSH do to your body?

In a normal pregnancy TSH should not affect your pregnancy symptoms too much, however, if you have high or low levels of TSH in your body you will probably experience more or stronger symptoms.

The symptoms of high TSH levels or hypothyroidism include: fatigue, loss of focus, muscle cramps, constipation and an inability to tolerate cold temperatures.

The symptoms of low TSH levels of hyperthyroidism include: fatigue, weakness, an increased or irregular heartbeat, sudden weight loss, nausea and vomiting.

Many of these symptoms are the same as many normal pregnancy symptoms, however most women who suffer from hypo- or hyperthyroidism during their pregnancies do have a history of thyroid conditions. Relax and talk to your midwife or physician if you have any concerns. If they think you are at risk, they will probably recommend a TSH blood test to diagnose the condition. However, chances are you’re just experiencing normal, pesky, pregnancy symptoms.

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