During pregnancy, the placenta, which connects your baby to your blood supply, acts as a temporary endocrine (hormone-producing) gland producing large amounts of oestrogen and progesterone to help the uterus grow.
Hormonal changes during pregnancy affect the entire body system. Here are just a few ways the endocrine system responds during pregnancy:
Increases in hormone levels and metabolic rates may cause pregnant women to feel warmer or have hot flushes.
The parathyroid gland grows slightly bigger to meet the increased need to calcium.
When the baby is ready to be born, the posterior pituitary gland will secrete oxytocin to initiate labour.
At birth, the anterior pituitary will secrete prolactin to stimulate the production of breast milk.
Common endocrine disorders that can occur in pregnancy are gestational diabetes and thyroid disorders.
Gestational Diabetes
Pregnancy causes your body to produce high levels of various hormones. Almost all of them impair the action of insulin in your cells, increasing the amount of insulin that is required and if you have gestational diabetes, raising your blood glucose levels.
Thyroid disease during pregnancy
Thyroid disease is the second most common endocrine condition in women of childbearing age after diabetes. The increased proteins in pregnancy mean that more thyroid hormone is also required. Immunity also changes in pregnancy. Both of these mean that pregnancy is a common time for thyroid disorders to occur.
Why is thyroid disease more common during pregnancy?
Thyroid problems sometimes can start or get worse during pregnancy or after childbirth because of the complex hormonal changes that take place, as well as changes in immunity that occur as part of every pregnancy.
The thyroid makes the hormones that control metabolism, that is, how your body uses and stores energy. When the thyroid does not make enough thyroid hormone, we call this under active thyroid or hypothyroidism. As we need more thyroid hormone in pregnancy, if the thyroid can’t meet this increased need then the result is hypothyroidism.
Hypothyroidism during pregnancy is not common. However, the symptoms can be overlooked because they are often the same symptoms of hormonal changes during a normal pregnancy, such as tiredness and weight gain.
In addition, due to altered immunity in pregnancy, people who are at increased risk of autoimmune diseases are likely to have a first episode or flare during or just after pregnancy. These conditions can cause both hyperthyroidism (overactive thyroid) and hypothyroidism (underactive thyroid).
Why is it important to treat thyroid disease during pregnancy?
A pregnant woman’s thyroid hormones are vital not only for her but also for the development of the baby. The baby doesn’t have a fully functioning thyroid of it’s own until 20 weeks of gestation, so it is reliant on maternal thyroid hormone until then.
Pregnant women with thyroid problems in pregnancy can get high blood pressure, anaemia (low red blood cell count), muscle pain and weakness. There is also a risk of miscarriage, stillbirth, premature delivery (before 37 weeks) and cause a permanent impaired neurological development of the baby.
Left untreated, hypothyroidism during pregnancy may have severe consequences. A blood test can find whether any symptoms are due to an underactive thyroid. Fortunately, hypothyroidism during pregnancy is easily treated with thyroid hormone replacement medication. The drug is the same as the hormone your body makes and is safe for pregnant women.
Hyperthyroidism in pregnancy can also be treated, but treatment should be discussed with your endocrinologist so it can be individualised to the cause and your personal circumstances.