Hashimoto's Disease And Pregnancy: What You Need To Know

Hashimoto's disease, a thyroid condition, can have several effects during pregnancy, on both the mother and the developing baby. However, taking the proper precautions to control the condition can prevent severe or lasting effects in most pregnancies. 

Here is an overview of everything you need to know about Hashimoto's disease and pregnancy.

What is Hashimoto's disease? 

Hashimoto's disease is an autoimmune disorder that primarily affects the thyroid. The body mistakes the thyroid as an enemy instead of an important organ and attacks the thyroid cells, causing them to produce an insufficient amount of thyroid hormones. Consequently,  the thyroid gland cannot function properly. This can impact:

• Metabolism

• Energy levels

• Fertility

• Digestion

• Mood

• Cognition

Although Hashimoto's disease does not have one clear cause, excessive exposure to radiation and iodine are known to make individuals more susceptible to developing the condition. Other risk factors are genetics, being female, and having other autoimmune disorders.

Hashimoto's disease can affect the body in a wide range of ways, and in pregnancy, it can cause concerning issues for both the mother and fetus. 

How does Hashimoto's disease affect fertility? 

Hashimoto’s disease can make conception more difficult for some women, although many with the condition do not report struggling to get pregnant. Carrying a healthy baby to term, however, can be more difficult because having the condition frequently leads to miscarriage, especially if the disease is severe or uncontrolled, and other complications. 

It is not uncommon for the condition to cause an irregular menstrual cycle because the condition impacts ovulation and the hormonal cycle. This can interfere with the woman’s ability to get pregnant.

Hashimoto's disease is connected to polycystic ovary syndrome (PCOS). Many studies¹ have reported a strong correlation between thyroid antibodies and specific causes of infertility such as PCOS, with a recent study² suggesting a genetic predisposition for having both conditions.

PCOS is an endocrine disorder characterized by ovarian cysts, ovarian dysfunction, hyperandrogenism (having a hairy body, acne, alopecia), and period irregularities. As a result, PCOS can lead to infertility, spontaneous abortion, preeclampsia, and gestational diabetes.³ 

Risks of Hashimoto's disease during pregnancy

Although some women with Hashimoto's disease experience fertility issues, the condition can make staying pregnant and delivering a healthy baby even more complicated for several reasons. Hashimoto's disease is a frequent cause of miscarriage, especially early in the pregnancy, and the condition can also lead to preeclampsia, placental abruption, and anemia. 

Miscarriage

Hashimoto’s disease can make carrying the baby to full term more difficult for many women. Miscarriage can occur for many reasons, but women with Hashimoto's disease are much more likely to lose a fetus⁴ before birth than an average woman who does not have the condition.

Many miscarriages related to Hashimoto's disease occur within the first eight weeks following conception, but they can occur at any stage of the pregnancy. Higher rates or recurrent miscarriages have been also reported.

Hashimoto's disease may contribute to miscarriage for several reasons. Women who are not aware that they have the condition before becoming pregnant tend to experience the most frequent miscarriages because they are unable to take preventative steps.

Once you are diagnosed with Hashimoto's disease, your doctor will prescribe a thyroid hormone replacement to ensure that your thyroid hormones are within the normal level needed for your body to function properly during pregnancy. The dosage of this medication must be precise to best support the health of the mother and baby.

Preeclampsia

Hashimoto's disease can also be associated with preeclampsia, a condition characterized by high blood pressure in pregnant women. It is more common during the second half of pregnancy. Severe cases can lead to many complications for the mother, including liver and kidney damage, and for the fetus such as:

• Fetal growth restriction

• Preterm birth

• Death

Symptoms of preeclampsia may involve:

• Headaches

• Upper abdominal pain

• Nausea and vomiting

• Shortness of breath

• Swelling in the hands and face

Women with Hashimoto's disease, as well as hyperthyroidism and other thyroid problems, are more likely to develop preeclampsia during pregnancy. Women who are obese, older than average child-bearing age, or have significant comorbidities (more than one disease or condition at the same time) during pregnancy may be more likely to develop severe preeclampsia.⁵

Women who experience preeclampsia and who do not currently have a thyroid condition may be more likely to develop one⁶ later in life. 

Placental abruption

Hashimoto’s disease is associated with higher rates⁷ of placental abruptions. Placental abruption, more common during the second half of pregnancy, occurs when the placenta detaches from the uterus too soon. 

During a healthy pregnancy, this should not happen until delivery. If the placenta is detached too early,  the baby's access to oxygen, blood, and nutrients will be blocked. Most placental abruptions lead to premature delivery unless the abruption is mild and able to repair itself, as it cannot be medically reattached. 

Moderate abruption will likely require hospitalization until the baby is born, and they may need to be delivered early. Severe abruptions will nearly always result in immediate delivery. 

Anemia

Women with Hashimoto's disease are more likely to experience anemia (low red blood cell levels) during pregnancy. Anemia, often arising due to a lack of iron or vitamin B12, can cause:

• Fatigue

• Dizziness

• Pale skin

• Lightheadedness

• Depression

• Chest pain

This can be worsened during pregnancy because Hashimoto's disease can affect the absorption of iron. Anemia during pregnancy is treated with iron supplements.

How does Hashimoto's disease affect the fetus? 

In addition to the above risks of Hashimoto's disease during pregnancy, if the condition goes untreated, the developing fetus can experience:

• Low birth weight

• Premature birth

• Stillbirth

The baby’s brain and nervous system are at particularly high risk of developmental problems because the thyroid hormone plays a major role in their development. 

Can Hashimoto's disease be diagnosed during pregnancy? 

It is not unusual for pregnancy to interfere with your hormone and thyroid levels,⁸ which can make diagnosing Hashimoto's disease or other thyroid issues somewhat more difficult during pregnancy. 

Other potential symptoms of Hashimoto's disease are also common side effects of pregnancy, such as:

• Fatigue

• Difficulty dealing with cold

• Constipation

• Muscle cramps

• Problems concentrating

This can make it difficult to tell the difference between a normal, healthy pregnancy and something more concerning.

However, pregnancy is a common time for the condition to be diagnosed because a woman may not know she has the condition until it interferes with her ability to get pregnant, causes a miscarriage, or leads to other pregnancy complications.

Testing to determine the cause of one or more of these problems can lead to a diagnosis of Hashimoto's disease. Hypothyroidism occurs in approximately 0.5%–3.5% of all pregnancies,⁹ with Hashimoto’s disease being the most common cause.

Hashimoto's disease is typically diagnosed by testing the thyroid function and antibody levels. Specific types of blood tests often used to diagnose Hashimoto's disease include:

• TSH (thyroid-stimulating hormone) test

• T-4 test

• Testing for the presence of an antibody to thyroid peroxidase (TPO)

Potential complications of Hashimoto's disease after giving birth

Hashimoto's disease causes plenty of challenges before and during pregnancy, but the potential for complications does not end when the baby is born. Even if the baby is healthy at birth, the mother is still at a high risk of postpartum hemorrhage, and recovery may be more difficult than for a woman who does not have Hashimoto's disease. 

Finding an OB-GYN who is experienced in working with patients with Hashimoto's disease and related disorders is an important step in managing potential complications related to the condition before, during, and after your pregnancy. 

Postpartum hemorrhage

Although any woman can experience postpartum hemorrhage, patients with Hashimoto's disease are at particularly high risk of hemorrhaging after giving birth. A recent study¹⁰ reported that postpartum hemorrhage was the most frequent maternal outcome, occurring in 38.8% of all studied cases.

Postpartum hemorrhage most commonly occurs during the first 24 hours following delivery. It involves heavy bleeding that can be difficult to control. This condition is most common when the contractions that deliver the placenta are not strong enough to adequately stop surrounding blood vessels from bleeding, and other organs can also tear during and after birth. 

Blood that does not clot adequately can also contribute to hemorrhaging, and Hashimoto's disease can significantly elevate the risk of experiencing bleeding that is heavy and difficult to control, leading to dangerously high levels of blood loss.

Postpartum hemorrhage can lead to several concerns beyond bleeding itself, such as:

• A drop in blood pressure

• Elevated heart rate

• Lowered red blood cell levels

• Fatality in some cases

Because this condition typically occurs within a short window of giving birth, most women who experience it are still in the hospital when they begin to hemorrhage, so access to medications and other treatment options is relatively easy.

Specific circumstances can vary, particularly if other health concerns may interfere with treatment. However, most hemorrhaging is treated with medications that help clot the blood and seal blood vessels, in addition to procedures that repair tissues or remove any pieces of placenta left in the uterus.

Uterine massage or other techniques may help to stimulate contractions or put pressure on the area to slow the bleeding. Surgery (laparotomy) may be used if the location of the bleeding cannot be found, and a hysterectomy may be used as a last resort if the bleeding cannot be stopped with other treatment options. 

Impact on recovery 

For the majority of women, the most significant links between Hashimoto's disease and pregnancy occur before and during pregnancy, but it is also possible to have a more complicated recovery process than someone who does not have the condition.

Occasionally, the elevated dose of thyroid hormone replacement medication, often given during pregnancy, could have a temporary negative impact after delivery, including:

• Frequent weakness

• Mood swings

• Irritability

• Difficulty swallowing

• An irregular heartbeat

It is, therefore, important to discuss any symptoms you may have with your doctor so they can readjust the dose if needed. 

Does Hashimoto's disease affect breastfeeding? 

Hashimoto's disease and other thyroid issues can impact a mother's ability to produce enough milk, and the milk may not flow well enough to reach the baby.

Although you may have treatment options to help improve milk production, using formula may be helpful or necessary until you can produce enough milk to provide your baby with enough nutrition.

When should I seek medical attention? 

Hashimoto's disease is generally an ongoing condition that simply requires frequent monitoring rather than immediate medical attention. However, there are certain circumstances under which seeking medical attention immediately may be necessary.

Symptoms of preeclampsia, bleeding, cramping, or fever may indicate a more significant problem that could severely harm you or your baby if left untreated.

The lowdown

Although Hashimoto's disease can make conceiving, carrying, and delivering a healthy baby more challenging, adequate medical interventions throughout the process can make a successful pregnancy possible for the vast majority of women.

Most concerns linked to the condition should merely be viewed as setbacks, rather than permanent infertility or reasons to avoid having children, as medications and other treatments can generally control them for the majority of women.

However, the complications that Hashimoto's disease can lead to are valid concerns that should be discussed frequently with your doctor, OB-GYN, or another medical professional before, during, and after pregnancy. This will provide every chance that both the mother and baby are kept healthy throughout the pregnancy, and during and after delivery.