Thyroid cancer and pregnancy Is there a risk to the fetus

Thyroid cancer is a condition that causes a lot of concern for many women, especially those who are planning to conceive or are already pregnant. The thyroid gland plays a crucial role in regulating the body's hormones, so any problem with it can affect both the health of the pregnancy and the developing baby. In this article on Dalily Medical, we will discuss how thyroid cancer impacts pregnancy, whether it poses any risks to the mother or the fetus, and how to safely monitor the condition during pregnancy. If you're wondering, "Can I have a normal pregnancy with thyroid cancer?" then this article is for you.

Can I Get Pregnant While Having Thyroid Cancer?
Yes, it’s definitely possible, but your doctor needs to carefully evaluate your condition. If the cancer is small and not spreading quickly, treatment can often be postponed until after delivery.

Does Thyroid Cancer Harm the Baby?
Usually no, especially if the cancer is diagnosed early and hasn’t spread. This means the pregnancy can be normal without complications.

Can I Have Thyroid Surgery While Pregnant?
It’s possible, but it’s generally better to delay surgery until after delivery unless there’s an urgent risk. If surgery is necessary, it’s safest to perform it during the second trimester (months 4 to 6).

Can I Take Radioactive Iodine Treatment While Pregnant?
Absolutely not. Radioactive iodine treatment is forbidden during pregnancy because it can harm the baby’s thyroid. This treatment must be postponed until after delivery and weaning.

If I Discover Thyroid Cancer After Delivery, When Should I Start Treatment?
You can start surgery and other treatments immediately after delivery. If radioactive iodine is needed, you must stop breastfeeding for at least 6 weeks before starting it.

Can I Get Pregnant Again After Thyroid Cancer Treatment?
Yes, but it’s best to wait 6 to 12 months after radioactive iodine treatment to ensure your body has cleared the radiation and the next pregnancy is safe.

Do I Need to Monitor Thyroid Hormones During Pregnancy?
Definitely yes, especially if your thyroid was removed. You will need to take hormone replacement medicine (levothyroxine) daily and have regular blood tests (TSH) to keep your hormone levels balanced for the baby’s growth.

Can the Baby Be Affected If the Mother Has Thyroid Problems?
If hypothyroidism (underactive thyroid) is untreated or poorly managed, it can affect the baby’s brain development. That’s why it’s essential to follow your treatment carefully during pregnancy.

Can Pregnancy Cause Thyroid Cancer to Return?
Currently, there is no scientific evidence that pregnancy causes thyroid cancer to come back. However, continuous follow-up with your doctor, especially during the first 5 years after treatment, is very important.

Is Pregnancy Risky If I Had My Entire Thyroid Removed?
No, pregnancy is not risky in this case, but you must strictly adhere to your hormone replacement therapy and have regular hormone level checks throughout pregnancy.

Do I Need to Change My Diet During Pregnancy If I Have Thyroid Cancer?
Generally, maintain a healthy and balanced diet. Before radioactive iodine treatment, avoid iodine-rich foods for a period. During pregnancy, your doctor will recommend the best diet based on your condition.

Could I Have Thyroid Cancer Symptoms While Pregnant Without Knowing?
It’s possible because pregnancy symptoms can resemble thyroid issues, such as neck swelling or voice changes. If you notice any lump or pain in your neck, you should get a medical check-up promptly.

Is Ultrasound Monitoring Important During Pregnancy If I Have Thyroid Cancer?
Yes, very important. Ultrasound is safe for the baby and helps doctors monitor the size of any tumor or changes in the thyroid or lymph nodes regularly.

Do Thyroid Medications Affect Pregnancy or the Baby?
Hormone replacement drugs like levothyroxine are very safe during pregnancy and are essential to keep you and your baby healthy.

Does Thyroid Cancer Increase the Risk of Preterm Birth?
Not directly, but sometimes treatment complications or hormone imbalances can affect pregnancy. That’s why regular medical follow-up is crucial.

Are There Risks for Breastfeeding After Thyroid Cancer Treatment?
If you took radioactive iodine treatment, you must stop breastfeeding for about 6–8 weeks. However, if you had thyroid surgery and only take hormone replacement therapy, breastfeeding is completely safe.

Does Pregnancy Affect Thyroid Hormone Levels After Treatment?
Yes, pregnancy changes your body’s hormone needs, so adjusting your medication dosage based on lab results regularly is very important.

Can Doctors Differentiate Between Pregnancy Symptoms and Cancer Symptoms?
Sometimes it’s difficult, but medical exams, ultrasound, and blood tests help doctors make the correct diagnosis.

Should I Tell My Doctor If I’m Pregnant and Have Thyroid Cancer?
Absolutely yes, you must inform your doctor immediately so they can arrange the safest treatment and follow-up plan for you and your baby.

Are There Cases When Pregnancy Is Not Recommended After Thyroid Cancer?
Rarely, but if the cancer is advanced or there are serious complications, your doctor may advise postponing pregnancy for a longer time.

Does Thyroid Cancer Affect Natural Fertility?
Usually no, the cancer itself does not affect fertility, but some treatments like radioactive iodine require waiting before trying to conceive.

Do I Need Different Hormone Tests While Pregnant?
Yes, because pregnancy affects hormone levels, so it’s important to monitor them regularly.

Are There Medications Forbidden for Thyroid Cancer Treatment During Pregnancy?
Radioactive iodine is strictly forbidden during pregnancy. Levothyroxine hormone therapy is safe and must be continued.

Can Pregnancy Cause Thyroid Cancer Symptoms to Appear or Worsen?
Pregnancy changes hormone balance, but there is no strong evidence that it worsens or spreads thyroid cancer. Still, regular follow-up with your doctor is essential.

Can I Have Imaging Tests Like Ultrasound During Pregnancy?
Ultrasound is very safe and widely used for thyroid monitoring during pregnancy. Other scans like radioactive iodine or CT scans are not safe and should be postponed.

Will I Need Additional Medications During Pregnancy?
You may need dose adjustments of levothyroxine or other drugs based on your test results.

Is Natural Birth Better or C-Section If I Have Thyroid Cancer?
In most cases, natural birth is safe and possible, but the final decision depends on your health and your doctor’s advice.

Can the Tumor Return After Pregnancy?
In some cases, yes, which is why post-delivery medical follow-up is very important.

Are There Foods or Habits to Avoid During Pregnancy Due to Thyroid Cancer?
Before radioactive iodine treatment, avoid iodine-rich foods. During pregnancy, a balanced diet is best for you and your baby’s health.

Can I See a Mental Health Specialist Due to Anxiety About Cancer’s Impact on Pregnancy?
Definitely yes, psychological support is very important and helps you manage anxiety, maintain mental well-being, and improve your quality of life.

Thyroid Cancer Survival Rates: Important Simple Information

Thyroid cancer is one of the cancers with very high treatment success, especially when diagnosed early.

• Papillary Thyroid Cancer:
  This is the most common type, affecting about 8 out of 10 people diagnosed.
  If the cancer is limited to the thyroid, the 5-year survival rate is nearly 100%.
  If it spreads to other parts (metastatic), the 5-year survival rate is around 80%, which is excellent.

• Follicular Thyroid Cancer:
  5-year survival is about 100% if limited, but drops to about 63% if spread.

• Medullary Thyroid Cancer:
  5-year survival is about 100% in early stages, dropping to 40% with spread.

• Anaplastic Thyroid Cancer:
  This is rare and more aggressive. The 5-year survival rate is about 31% if localized and only 4% if spread.

Is thyroid cancer curable?

Yes, most cases of thyroid cancer are treatable and curable, especially if the disease is diagnosed early before it spreads widely.

If treatment can’t completely eliminate the cancer, your doctor will develop a management plan to control the disease, which helps reduce tumor size and prevent it from growing or spreading again.

What is thyroid cancer?

Thyroid cancer is a disease that begins in the thyroid gland — a small butterfly-shaped gland located at the base of the neck. This gland produces important hormones that regulate metabolism, meaning it helps your body use energy properly. Thyroid hormones also control body temperature, blood pressure, and heart rate.

Thyroid cancer is a type of endocrine cancer, but the good news is it is highly treatable, with a very high cure rate when detected early.

How common is thyroid cancer?

About 53,000 people are diagnosed with thyroid cancer annually in the United States. Most cases improve significantly after treatment, but unfortunately, around 2,000 deaths occur each year.

The disease affects women about three times more often than men, commonly appearing in women in their 40s and 50s. For men, it usually shows up in their 60s and 70s. Children can get it too, but this is much less common.

Types of thyroid cancer

Thyroid cancer has different types, distinguished by the shape of cancer cells and how fast the disease spreads. Here are the most common types:

1. Papillary thyroid cancer

   • The most common type, accounting for about 70–80% of cases.

   • Grows slowly and usually starts in one part of the thyroid.

   • May spread to lymph nodes in the neck but is easy to treat, with a very high cure rate.

2. Follicular thyroid cancer

   • Makes up about 10–15% of cases.

   • Sometimes spreads to other organs like the lungs or bones.

   • If treated early, the cure rate is good but slightly lower than papillary cancer.

3. Anaplastic (undifferentiated) thyroid cancer

   • Very rare (less than 2%) but very aggressive and fast-growing.

   • Difficult to treat and rarely curable.

   • Mostly affects older adults.

4. Medullary thyroid cancer

   • Accounts for about 3–4% of cases.

   • Originates in special cells that produce calcitonin hormone.

   • Can be hereditary in some cases and linked to MEN syndrome (Multiple Endocrine Neoplasia).

5. Other rare types:

   • Thyroid lymphoma: Starts in immune system cells within the thyroid, often in people with chronic thyroid inflammation (like Hashimoto’s disease). Grows quickly but responds well to chemotherapy and radiation.

   • Metastatic thyroid cancer: Not starting in the thyroid, but spread from other cancers like breast or lung to the thyroid.

   • Thyroid sarcoma: Very rare, starts in connective tissue inside the thyroid. Grows rapidly and aggressively, usually requires urgent surgery.

   • Squamous cell carcinoma: Very rare, presents as a solid, fast-growing tumor often linked to undifferentiated cancer.

   • Mixed thyroid cancer: Combines two types, like papillary and medullary together. Rare and requires special treatment.

Stages of Thyroid Cancer

The stages of thyroid cancer vary depending on the tumor size, how far it has spread in the body, and the patient’s age. This classification is important because it helps the doctor determine the best treatment plan and estimate the chances of cure.

Classification by Age

• If you are under 55 years old:
  There are only two stages of the disease.

• If you are 55 years old or older:
  The disease is divided into four stages (Stage 1 to Stage 4).

Patients under 55 years old

• Stage 1:
  Cancer is limited to the thyroid or has spread slightly to nearby lymph nodes, with no distant metastasis.

• Stage 2:
  Cancer has spread to distant organs such as the lungs or bones.

Patients 55 years old or older

• Stage 1:
  The tumor is less than 4 cm in size and confined to the thyroid gland without spreading anywhere else.

• Stage 2:
  The tumor is larger than 4 cm or has spread to nearby lymph nodes, but only within the neck area.

• Stage 3:
  Cancer has started to spread outside the thyroid to nearby tissues such as the larynx or trachea, or to more distant lymph nodes.

• Stage 4:
  Cancer has spread to distant organs like the lungs, liver, or bones. This stage is further divided into sub-stages depending on tumor size and spread.

Warning Signs of Thyroid Cancer

Thyroid cancer often starts without clear symptoms, but there are signs you should watch for, especially if they persist or worsen over time:

• A lump or swelling in the neck:
  You may feel it when swallowing or by touching your neck. Usually painless but tends to grow over time.

• Change or hoarseness in the voice:
  If hoarseness lasts more than two weeks without clear cause, the tumor might be pressing on the nerves controlling the vocal cords.

• Difficulty swallowing:
  When the tumor presses on the esophagus.

• Difficulty breathing or feeling of choking:
  If the tumor presses on the windpipe (trachea).

• Swelling of lymph nodes in the neck:
  You may feel small lumps under the jaw or on the sides of the neck.

• Pain in the neck or throat:
  Rare, but if persistent and accompanied by other symptoms, see a doctor.

Signs of Thyroid Cancer Spread (Metastasis)

When thyroid cancer spreads beyond the thyroid to other parts of the body, this is called advanced or metastatic cancer. The signs depend on where the cancer has spread:

1. Spread to lymph nodes in the neck:

   • Swelling or a hard lump on the side of the neck.

   • Usually painless but grows over time.

   • Sometimes multiple lumps appear in different neck areas.

2. Spread to the lungs:

   • Persistent cough that doesn’t improve with usual treatment.

   • Shortness of breath or feeling of insufficient air.

   • Occasionally coughing up blood (rare).

   • Chest pain or heaviness.

3. Spread to the bones:

   • Severe, persistent bone pain, especially in the spine, pelvis, or legs.

   • Bones become weak and prone to fractures.

   • Swelling in certain body areas.

4. General signs of cancer spread:

   • Unexplained fatigue and weakness.

   • Unintended weight loss.

   • Loss of appetite.

   • High blood calcium levels, especially in medullary thyroid cancer, causing:

     • Excessive thirst.

     • Frequent urination.

     • Irregular heartbeat.

     • Confusion or dizziness.

How Does Thyroid Cancer Affect Pregnancy?

Thyroid cancer can affect pregnancy, but the good news is that most cases are managed safely whether before or during pregnancy. Here are the details:

1. If thyroid cancer is discovered during pregnancy

• Does cancer affect the baby?
  Usually no, especially if it is a slow-growing type like papillary or follicular thyroid cancer.

• Is immediate surgery necessary?
  Most doctors delay surgery until after delivery if the condition is stable and no serious symptoms appear.

• Monitoring during pregnancy:

  • Regular ultrasound scans to monitor the thyroid and tumor.

  • Blood tests to check thyroid hormone levels.

  • Sometimes a fine needle biopsy if the lump looks suspicious.

  • Surgery may be considered in the second trimester (around 4th to 6th month), which is the safest time for surgery during pregnancy.

2. Effect of thyroid cancer treatment on pregnancy

• Radioactive iodine therapy:
  Absolutely contraindicated during pregnancy and breastfeeding because it can harm the baby. It must be postponed until after birth and after breastfeeding is finished.

• Surgery (thyroidectomy):
  Can be delayed if cancer is not advanced. If surgery is done during pregnancy, the safest period is the middle trimester (months 4 to 6) to minimize risks to the fetus.

3. If You Become Pregnant After Thyroid Cancer Treatment

There is no problem with pregnancy after treatment, but it is recommended to wait at least 6 to 12 months after radioactive iodine therapy.

You must closely monitor your thyroid hormone levels during pregnancy because your body might not produce these hormones naturally after thyroid removal.

You will take a hormone replacement called Levothyroxine throughout pregnancy, and the dose will be adjusted based on blood tests.

Recovery Time After Thyroid Cancer Treatment: What You Need to Know

Recovery time varies depending on the type of treatment and the individual’s condition, but here is a general overview and the typical stages:

1. After Thyroidectomy (Surgical Removal of the Thyroid)

   • Hospital stay: From 1 to 3 days depending on the case.

   • Home recovery: Most people return to normal life within 2 to 3 weeks.

   • You must care for the surgical wound well and take important medications like calcium supplements and thyroid hormone replacement (Levothyroxine).

2. After Radioactive Iodine (RAI) Therapy

   • Preparation: You may need to stop certain medications or follow a special diet for about two weeks before the dose.

   • Isolation period: After the dose, you need to isolate yourself for 3 to 7 days due to radioactive activity.

   • Fatigue and symptoms: Fatigue and weakness may last from two weeks to a month. Some people experience dry mouth or changes in taste, which gradually improve.

3. Follow-up After Treatment

   • Regular monitoring through:

     • Thyroid hormone tests (TSH).

     • Special tests like thyroglobulin to ensure cancer has not returned.

     • Imaging tests (scans or X-rays) depending on the patient’s condition.

   • Follow-up may continue for years (5 years or more) for reassurance, but this does not mean recovery hasn’t happened.

4. When Can You Return to Normal Life?

Effects of Thyroid Cancer on Pregnant Women and the Fetus: What You Need to Know

Thyroid cancer affects the health of both mother and fetus in different ways, especially if not managed properly. Here are the main effects explained simply:

1. Effects on the Pregnant Mother

   • It can cause severe fatigue, weight loss, or breathing and swallowing difficulties if the tumor is large.

   • Treatments like surgery or radioactive iodine are not always safe during pregnancy, which can complicate things.

   • Thyroid hormone imbalances during pregnancy can worsen pregnancy symptoms and harm the mother’s health.

2. Effects on Fetal Development

   • Untreated maternal hypothyroidism (low thyroid hormones) may cause problems in fetal brain development and general growth delay.

   • Radioactive iodine is forbidden during pregnancy because it can damage the fetal thyroid and cause serious problems.

3. Risk of Preterm Birth and Pregnancy Complications

   • Cancer or its treatments may increase the risk of premature birth or fetal growth restriction.

   • Pregnancy-related high blood pressure (preeclampsia) may occur, threatening both mother and fetus.

4. Psychological Impact on the Mother

   • Anxiety and stress due to the illness and its effects on pregnancy can negatively affect both mother and fetus.

5. Immune System Issues

   • Cancer weakens the immune system, and pregnant women naturally have reduced immune activity, increasing infection risk.

6. Neurological Development Problems in the Fetus

   • Low thyroid hormones can delay brain and nervous system development, affecting the child’s intelligence and mental growth.

7. Fetal Growth Restriction and Low Birth Weight

   • The baby may be born smaller than normal, leading to health problems after birth.

8. Effects of Treatments on Pregnancy

   • Some treatments, especially in the first trimester, may stress the body and reduce its ability to support pregnancy.

9. Emotional and Psychological Effects on Pregnancy

   • Continuous stress and anxiety may raise stress hormones, leading to complications like premature birth or low fetal weight.

Treatment of Thyroid Cancer During Pregnancy and Fetal Considerations

Managing thyroid cancer during pregnancy requires great care to protect both mother and fetus. Here is a simple explanation of treatment steps and important precautions:

1. Diagnosis and Monitoring

   • The first step is diagnosis using ultrasound (which is safe and has no harmful radiation).

   • Sometimes a needle biopsy is needed to confirm the tumor type.

   • Tumor size and the condition of mother and fetus are monitored continuously.

2. Surgical Treatment

   • If surgery is necessary, it is preferably postponed to the second trimester (months 4 to 6), which is the safest period for the fetus.

   • In very rare cases where the cancer threatens the mother’s life, surgery can be done anytime with careful medical monitoring.

3. Radioactive Iodine Therapy

   • Completely forbidden during pregnancy because it harms the fetal thyroid and can cause severe problems or fetal death.

   • This treatment is postponed until after delivery.

4. Medication (Thyroid Hormone Replacement)

   • After thyroid removal or during follow-up, you will take Levothyroxine to replace thyroid hormone.

   • This medication is very safe during pregnancy, and the dose is adjusted based on regular blood tests.

5. Regular Follow-up

   • Pregnancy should be regularly monitored by an obstetrician.

   • Endocrinologists or oncologists also follow-up on thyroid function and cancer status.

   • Fetal growth and health are monitored continuously.

6. Delivery and Postpartum Follow-up

   • After delivery, radioactive iodine or other treatments can be safely started.

   • If you plan to breastfeed, you must stop breastfeeding 6–8 weeks before starting radioactive iodine treatment to protect your baby.

Specialists Involved in Treating Thyroid Cancer During Pregnancy

• Endocrinologist: Specialist in thyroid diseases and hormone regulation, monitors hormone levels and treatment.

• Oncologist: Handles chemotherapy, radiotherapy, and overall cancer management.

• Head and Neck Surgeon or Endocrine Surgeon: Performs thyroidectomy or surgeries related to thyroid tumors.

• Obstetrician: Monitors pregnancy and fetal health, coordinating with other specialists.