Abnormalities of Thyroid function are common in pregnancy. Screening of thyroid function is now routine practice.
An underactive thyroid in the mother may potentially affect normal fetal brain development.
An overactive thyroid in the mother can result in increased risk of miscarriage and also the capacity to suppress normal fetal thyroid function.
Learn more about Thyroid disease in pregnancy
Pre pregnancy counselling is important to screen women planning a pregnancy and this should include screening for thyroid disease. It also important to recognise that abnormal thyroid function can affect a woman’s fertility, and then in turn it can have adverse effects on the pregnancy. These risks may include the potential of miscarriage, poor fetal brain development and also the suppression of normal fetal thyroid development.
Thyroid disease will often be caused by auto immune disorders such as Hashimotos Disease and Graves disease. It can also occasionally be caused by a deficiency in maternal iodine intake.
Thyroid disease ultimately relates to either an underactive or overactive thyroid.
If a woman planning a pregnancy has abnormal thyroid function she should be seen by an endocrinologist. Relevant tests for thyroid function and auto antibody testing need to be performed to identify the nature of the thyroid dysfunction.
It is wise in these circumstances that their thyroid function is well controlled before pregnancy commences.
The routine screening tests in pregnancy must always include thyroid function tests. Very often a transient and insignificant abnormality may be identified and in this instance the tests need to be repeated. If the subsequent tests show an underactive thyroid the mother will be commenced on thyroid supplements (thyroxine) and auto antibody tests will be requested. If the thyroid is noted to be overactive then the patient will be reviewed urgently by an endocrinologist and commenced on medication to suppress the overactive thyroid (Carbimazole or Propylthyouracil).
If this all sounds too complicated then don't worry. Problems in pregnancy happen when the obstetrician doesn't perform the relevant tests.
If thyroid disease is diagnosed, monitored and treated no problems will occur.