Managing Hyperthyroidism During Pregnancy: Risks and Treatment Options

Hyperthyroidism in Pregnancy

Hello, Doctor: I am currently 34 weeks pregnant, and my doctor has diagnosed me with hyperthyroidism with T3: 191, T4: 15.8, and TSH: 1.51.
The doctor prescribed Propranolol tablets for me to take, two times a day, one tablet each time.
What effects will this have on my baby and me? Is it possible to not take the medication? Will my baby inherit hyperthyroidism after birth? Previously, an endocrinologist mentioned that pregnant women should be monitored based on free T4 levels, but this time, my obstetrician said that since my T3, T4, and TSH levels are all elevated, there is no need to check free T4.
Is that correct?

Jiajia, 20~29 year old female. Ask Date: 2004/10/08

Dr. Yang Hongzhi reply Internal Medicine

Procil is considered one of the antithyroid medications with a lower placental transfer.
However, a small portion can still cross the placenta, potentially leading to some suppression of fetal thyroid function.
Therefore, it is recommended to keep the dosage as low as possible, while also avoiding significant hyperthyroidism in the mother.
Hyperthyroidism has a genetic predisposition and typically does not manifest at birth.
However, in rare cases, antibodies from the mother that cause hyperthyroidism can be transmitted to the fetus through the placenta, resulting in transient hyperthyroidism in the newborn.
During pregnancy, T3 and T4 levels may appear falsely elevated, so it is common to measure FT4.
Additionally, TSH levels are also assessed; in cases of hyperthyroidism, TSH levels will be decreased.

Reply Date: 2004/10/08

More Info

Managing hyperthyroidism during pregnancy is a critical concern, as it can significantly impact both maternal and fetal health. Hyperthyroidism, characterized by elevated levels of thyroid hormones (T3 and T4) and suppressed TSH, can lead to various complications if not properly managed. In your case, with T3 at 191, T4 at 15.8, and TSH at 1.51, it indicates that you are experiencing hyperthyroidism, and your physician has prescribed Propranolol (often referred to as Procil in some regions) to help manage your condition.

Risks of Untreated Hyperthyroidism During Pregnancy
1. Maternal Risks: Untreated hyperthyroidism can lead to serious complications for the mother, including:
- Preeclampsia: A condition characterized by high blood pressure and potential damage to other organ systems, often the liver and kidneys.

- Heart Problems: Increased heart rate and potential heart failure due to the increased workload on the heart.

- Thyroid Storm: A rare but life-threatening condition characterized by an extreme increase in thyroid hormone levels, leading to severe symptoms such as fever, rapid heart rate, and confusion.

2. Fetal Risks: The fetus is also at risk if the mother’s hyperthyroidism is not managed:
- Low Birth Weight: Babies born to mothers with uncontrolled hyperthyroidism may be smaller than average.

- Preterm Birth: There is an increased risk of premature delivery.

- Neonatal Hyperthyroidism: If the mother has high levels of thyroid hormones, the baby may also be born with hyperthyroidism, especially if the mother has thyroid antibodies.

Treatment Options
The use of antithyroid medications, such as Propranolol, is generally considered safe during pregnancy when prescribed by a healthcare provider. Propranolol can help manage symptoms like rapid heart rate and anxiety, but it does not directly reduce thyroid hormone levels. The primary medications used to control hyperthyroidism during pregnancy are Methimazole and Propylthiouracil (PTU). PTU is often preferred in the first trimester due to its safety profile, while Methimazole is typically used in the second and third trimesters.

Importance of Monitoring
Your concern about the free T4 levels is valid. Free T4 is a crucial marker for assessing thyroid function, especially in pregnant women. While your obstetrician may have decided not to check free T4 based on your elevated T3 and T4 levels, it is essential to monitor all thyroid function tests regularly. This helps ensure that your treatment is effective and that your thyroid hormone levels are within a safe range for both you and your baby.

Genetic Considerations
As for the hereditary aspect, while hyperthyroidism itself is not directly inherited, certain thyroid conditions can have a genetic component. If you have a history of thyroid disease in your family, it may increase the likelihood of your child developing thyroid issues later in life. However, the immediate concern is managing your current hyperthyroidism to minimize risks during pregnancy.

Conclusion
In summary, it is crucial to adhere to your physician's recommendations regarding medication and monitoring. Discontinuing medication without medical advice can lead to significant risks for both you and your baby. Regular follow-ups with both your obstetrician and endocrinologist are essential to ensure that your thyroid levels are managed effectively throughout your pregnancy. If you have concerns about the medication or its effects, discussing these with your healthcare provider can help you make informed decisions about your treatment plan.

Similar Q&A

Managing Hyperthyroidism During Early Pregnancy: Risks and Considerations

Three weeks ago, I was diagnosed with hyperthyroidism, and a week ago, I found out that I am 25 days pregnant. My husband and I really want to have a child, and after trying for three months, I discovered my hyperthyroidism. The doctor advised us to wait until my hyperthyroidism ...

Dr. Yang Hongzhi reply Internal Medicine
Hyperthyroidism during pregnancy is a relatively common condition. Although it does increase some risks, in most cases, it does not necessitate the termination of the pregnancy. In the majority of situations, medication can still yield favorable outcomes.

Managing Hyperthyroidism: Key Considerations for Pregnancy and Infant Health

As a patient with hyperthyroidism who has been receiving treatment at National Taiwan University Hospital for nearly five years, what precautions should I take when preparing for pregnancy? What effects does hyperthyroidism have on the baby?

Dr. Zeng Fenyu reply Internal Medicine
Hello Bobo! 1. If maternal hyperthyroidism is left untreated, the fetus is at risk for low birth weight and there is also a possibility of miscarriage. 2. Thyroid function should be monitored during pregnancy, and if there is still hyperthyroidism, treatment should follow the ...

Thyroid Dysfunction During Pregnancy: Risks and Treatment Options

I just found out that I have thyroid dysfunction at 30 weeks of pregnancy, and I have many red spots on my palms. I would like to ask the doctor: 1. What impact will this have on the baby, and what preventive measures should I take? 2. Can I receive treatment during pregnancy, an...

Dr. Yang Hongzhi reply Internal Medicine
Uncontrolled hyperthyroidism can affect both the mother and the fetus, so treatment is necessary. Currently, the primary treatment for hyperthyroidism during pregnancy is medication. Antithyroid drugs can impact the fetal thyroid, but they do not significantly increase the risk o...

Thyroid Hyperactivity: Key Considerations for Pregnancy Planning

What precautions should patients with hyperthyroidism take before preparing for pregnancy? Will hyperthyroidism during pregnancy have any effects on the fetus?

Dr. Lin Zhemin reply Surgery
The thyroid gland affects the fetus, and hyperthyroidism can lead to infertility. It is necessary to treat the thyroid condition first, and only after returning to normal levels can there be a chance of conception. During pregnancy, it is essential to maintain normal thyroid leve...