Is Pregnancy Safe with Hypothyroidism?

By BSc, MSc (embryologist) and BA, MA (fertility counselor).
Last Update: 07/08/2014

Hypothyroidism is an endocrine disorder in which the thyroid gland does not produce enough thyroid hormone. This is a condition that can be successfully treated.

In some cases, the symptoms tend to be subtle and can be mistaken for another conditions or diseases. A person can remain undiagnosed for years. Both men and women are exposed to suffer from hypothyroidism, but it is more prevalent in women.

An autoimmune problem is the most typical cause of hypothyroidism. Some antibodies of the immune system attack the thyroid gland thus altering its hormone production.

Below you have an index with the 5 points we are going to deal with in this article.

Symptoms and diagnosis

Symptoms depend on each person and are difficult to spot. Sometimes they can be mistakenly identified as symptoms of depression. Common symptoms are constipation, skin dryness and paleness, swollen face, hands and feet, hoarseness, slowed speech, fatigue, unintentional weight increase, profuse menstruations, higher sensitivity to coldness, and cramps. Not all of these symptoms may appear.

Hypothyroidism can be diagnosed through a blood test, which will reflect the values of the thyroid hormones and the thyroid stimulating hormones (TSH) released by the hypophysis.

Pregnant women are fully examined. A study of free T4, TSH, and anti-thyroid autoantibodies is conducted.

Problems during pregnancy

Hypothyroidism may happen before or after pregnancy. Unfortunately, many of the symptoms can be mistaken for those of the pregnancy, so the disease is not treated nor diagnosed.

Hypothyroidism can affect fertility since it prevents egg production, causes as well irregularities in the menstrual cycle, and facilitates an increasing prolactin, an hormone whose excessive production hinders ovulation in non-pregnant women.

In pregnant women, hypothyroidism may lead to a spontaneous abortion, being the probability four times higher than the average. That is the reason why finding out if there is hypothyroidism before getting pregnant, or at least in its early stages, is crucial.

Without treatment, women are in danger of developing hypertension, having a preterm birth or having children with an incomplete intellectual development.


The problem arises when a pregnant woman is not aware she has hypothyroidism. This happens often, but nowadays more cases are diagnosed, cases that used to go unnoticed because analysis were not as accurate as today, specially analysis of TSH levels.

Once diagnosed, the mother will take a medication based on a hormone replacement therapy. In order to avoid any problem, it is essential to take this medication following the timings and the procedure.

There is a chance doctors may prescribe a slight increase of the dosage, given that during pregnancy the thyroid is asked to make an overstrain up to the 50%. A lacking thyroid is really demanded during pregnancy, and will eventually fail in the subsequent months if it's not properly treated.

The treatment is quite simple: the patient only needs to take a pill a day. That pill will replace the hormone the thyroid is not producing. The treatment does not entail any risk for both the mother and the fetus. Once the child is born, a series of tests are conducted to check everything is fine. There are very rare cases of neonatal hypothyroidism; adults are usually who suffer that condition.


It is necessary to go to the doctor as soon as the woman notices she may be pregnant. The specialist, depending on the results shown by the analysis, will make the proper adjustments in the dosage in order to have a healthy, successful pregnancy. It is crucial to take the medication as indicated by the doctor.

Thyroid medication has to be taken with an empty stomach, at least one or two hours after meals. Concomitant use with antacids or vitamins is not advised.

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 Neus Ferrando Gilabert
Neus Ferrando Gilabert
BSc, MSc
Bachelor's Degree in Biology from the University of Valencia (UV). Postgraduate Course in Biotechnology of Human Assisted Reproduction from the Miguel Hernández University of Elche (UMH). Experience managing Embryology and Andrology Labs at Centro Médico Manzanera (Logroño, Spain). More information about Neus Ferrando Gilabert
Adapted into english by:
 Sandra Fernández
Sandra Fernández
Fertility Counselor
Bachelor of Arts in Translation and Interpreting (English, Spanish, Catalan, German) from the University of Valencia (UV) and Heriot-Watt University, Riccarton Campus (Edinburgh, UK). Postgraduate Course in Legal Translation from the University of Valencia. Specialist in Medical Translation, with several years of experience in the field of Assisted Reproduction. More information about Sandra Fernández

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