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Houston Fertility Journal

    Can thyroid problems affect fertility?

    August 17, 2018 / by Center of Reproductive Medicine   

    Center of Reproductive Medicine


    If you have been trying to conceive for awhile now with no success, one of the possibilities is, is that your thyroid could not be functioning the way it should. There are a lot of explanations for infertility in men and women, but not a lot of people are aware that poor thyroid function is one of them. Both males and females need a healthy thyroid in order to conceive and to maintain the pregnancy.

    As thyroid dysfunction is more common than people realize, it is important that this possibility is ruled out for everyone in the early stages of searching for the cause of infertility. But before we get into exactly how the thyroid plays a part in all of this, you will first need to know what your thyroid does for you and what type of issues can arise when it stops doing what it should.

    What does the Thyroid Gland do?

    The thyroid gland is located just beneath the voice box and above the collar bones. Each and every one of a human being’s cells depends on the thyroid to regulate the body’s:

    • Metabolism
    • Blood calcium levels
    • Energy production
    • Fat metabolism
    • Oxygen utilization
    • Balance of other hormones
    • & Weight maintenance

    The hormones that the thyroid affects include:

    • The Thyroid Releasing Hormone. This hormone is released from the hypothalamus in the brain and stimulates the pituitary gland at the base of the brain to release the Thyroid Stimulating Hormone.
    • The Thyroid Stimulating Hormone. This hormone stimulates the thyroid gland to produce Thryoxine (T4) and Triiodothyronine (T3).

    What can affect the Health of the Thyroid?


    Issues with the thyroid generally stem from:

    • Infections
    • Autoimmune disorders
    • Nutrient deficiencies
    • High levels of stress
    • Genetics
    • Exposure to toxins such as electromagnetic radiation, chemicals, pesticides, mercury and fluoride

    Hypothyroidism vs. Hyperthyroidism

    Two common conditions resulting from thyroid dysfunction are hypothyroidism and hyperthyroidism. Though they both stem from the same gland, they actually have an opposite effect on your body. Hypothyroidism refers to an under-active thyroid, meaning the thyroid gland is no longer making enough thyroid hormone for the body.

    On the flip side, hyperthyroidism refers to an overactive thyroid, meaning it is making too much.

    Symptoms of Hypothyroidism include:

    • Fatigue
    • Forgetfulness
    • Dy skin
    • Dry hair
    • Hair loss and damage
    • Brittle nails
    • Feeling cold
    • Constipation
    • Weight gain
    • Muscle cramps
    • Depression
    • Decreased menstrual flow
    • Slow heart rate
    • Swelling at the front of the neck
    • Sexual Dysfunction
    • Urge to overeat

    Symptoms of Hyperthyroidism include:

    • Overheating
    • Sweating
    • Difficulty sleeping
    • Racing thoughts
    • Inability to focus on one thing
    • Constant forgetfulness
    • Loosening of the bowels
    • Elevated heart rate, including palpitations
    • Irritability and high anxiety
    • Weight loss
    • Problems with menstruation
    • Fatigue

    How poor Thyroid Health affects Conception


    Poor thyroid function will get in the way of the body’s reproductive hormones.

    In Women

    In order for a woman to conceive, a few very important events must occur. There is only a small window of time for the sperm to be able to fertilize an egg within each month. Some examples of how thyroid dysfunction can disrupt reproduction in women include:

    High Prolactin Levels. High levels of Thyroid Releasing Hormone and low levels of Thyroxine can cause too much prolactin, which is usually produced by the pituitary gland to promote lactation. This will cause issues with fertility by disrupting the ovulation cycle, making it irregular or absent altogether.

    Low Body Temperature. When the thyroid is low functioning, it will also cause the basal body temperature to lower. The cells that divide in the embryo must be at a certain temperature range in order for the division to actually take place. If the basal body temperature is not high enough, the embryo may have difficulty growing. Because of this, the mother could be at risk of an early miscarriage.

    Anovulatory Cycles. This is another way to say lack of ovulation, meaning the female is not releasing any eggs to be fertilized. In order for the ovary to release the egg, it must be stimulated by the Luteinizing Hormone. Poor thyroid hormone levels will disrupt the Luteinizing Hormone’s ability to do this. It is still possible to menstruate regularly without ovulation, so it is not necessarily obvious when this is occurring.

    Luteal Phase Problems. All fertilized eggs must be nurtured for 13-15 days. The second half of the menstrual cycle, the Luteal Phase, depends on progesterone production, which could end up being too short due to thyroid issues. In this case, the fertilized eggs will not be able to implant securely and will leave the body with the menstrual cycle. This is technically considered a very early miscarriage, though many often mistake it to be a regular period.

    Other Hormonal Imbalances. The hormone balance can be affected by a number of things, such as a reduced sex hormone binding globulin, estrogen dominance and progesterone deficiency. Estrogen can literally dominate the thyroid hormones so they are suppressed and unable to function properly. In order for the thyroid to function normally, progesterone and estrogen levels must be balanced.

    Loss of libido. As the thyroid can affect both the male and female’s sex drive, the lack of sexual desire will no doubt make it difficult to find the time to achieve conception. With other hormone imbalances combining with fatigue and mood changes, the libido can be greatly affected.

    In Men

    Men can have just as much of an effect on the health of the pregnancy as the woman do. Commonly, thyroid problems in males are often due to lifestyle factors that end up messing with the quality of their sperm, in turn, making it difficult for the couple to conceive.

    Thyroid activity plays a large role in spermatogenesis/sperm production. The nurture cells for sperm within the testicles, steroli cells, are covered with a large amount of thyroid hormone receptors. T3 (the active thyroid hormone) helps the sperm to produce and swim.

    Poor thyroid health in men can mean:

    • Reduced testosterone production
    • Lowered libido
    • Erectile dysfunction
    • Poor testicular function
    • Reduced sperm numbers and motility
    • Both hyper and hypothyroidism can make increased levels of oxidative stress with can harm the sperm

    Hypothyroidism In Pregnancy

    It is extremely important that hypothyroidism is diagnosed immediately if the woman is already pregnant. The fetus will not be able to make its own thyroid hormone until it nears the 10th week of gestation. Meanwhile, it will be dependent on the mother’s hormone production.

    Severe hypothyroidism existing within the 1st trimester has been known to be responsible for many serious complications including:

    • Pre-eclampsia (high blood pressure during pregnancy)
    • Placental abruption (separation of the placenta from the wall of the uterus)
    • Preterm bird
    • Low birth rate
    • & Fetal death

    Babies that are born can suffer from:

    • Neurological impairment
    • Mental retardation
    • & Intellectual impairment

    Though it is rare for a woman to be able to achieve pregnancy with hypothyroidism, the potential risk factors that result from it are enough to be sure that it is nonexistent within both couples.

    Treatments for Hypothyroidism

    Hypothyroidism treatment consists of medicine that will boost your levels of the thyroid hormone. It will not cure the issue, but it can keep it under control. The most commonly used treatment is levothyroxine (Levoxyl, Synthroid, Tirosint, Unithroid, Unithroid Direct), which is medicine made to replace the thyroid hormone thyroxine. It is meant to behave just like the hormone normally would within your body, and should make you feel much better.

    Treatments for Hyperthyroidism

    There are a few different ways to treat an overactive thyroid. Your doctor will determine which one is best for you based on your age, what is causing the issue, and the state of your overall health. Examples of medicines that are typically used are:

    Radioactive Iodine. This is a medication taken by mouth that is meant to help lessen the size of the thyroid. It is expected to take 3 to 6 months to have an affect. Though, due to the fact that it slows down the the thyroid, there is a risk of hypothyroidism as a result. If this does occur, a change in medicine will be required. Radioactive iodine has been used to treat hyperthyroidism for over 60 years and is used to treat more than 70% of adults with the condition today.

    Antithyroid Drugs. Sometimes, medicines that block the thyroid’s ability to produce thyroid hormones may be used. Methimazole and propylthiouracil have been used for this to control symptoms and handle the issue on a long term basis. These medicines typically relieve symptoms within 3 months, but should be used for up to 18 months to avoid the chance of a relapse.

    When to Visit a Doctor & Testing for Thyroid Dysfunction


    If you are having trouble conceiving, it is recommended that you speak to a fertility specialist after 12 months of trying. However, if you are 32 years or older, you should speak to one after 6 months. If you are concerned that you may have a thyroid issue, this is something to investigate immediately. Consider the common signs and symptoms and make a checklist for yourself before speaking to doctor. 

    Body Temperature

    Know that routine blood tests may appear to be “normal” because the issue will be occurring within the cells and not the blood. In order to assess thyroid function, oral temperature can be taken in the morning before moving from the bed for 7-10 days. For best results, it should be done within 14 days of the menstrual cycle. A body with a healthy thyroid will produce a  temperature between 36 degrees and 37 degrees C, but it should ideally be above 36.5 degrees C.

    Blood Tests

    To fully test the thyroid, you will need to get readings for TSH, T4, T3, rT3 and Thyroid Antibodies. It may also be necessary to get a reading of TRH. When it comes to fertility health, the Thyroid Stimulating Hormone level should be between 1 and 2 mIU/L, Thyroxine between 16-20 pmoI/L,Trilodiothyronine between 4.5-6.0 pmoI/L, reverse T3 below 250 pmoI/L and O IU/ml for thyroid antibodies. These tests will can be done by your personal physician.

    Diet and Lifestyle

    Because of the popular diet in America, many are suffering thyroid health problems. Food has a large affect on the thyroid. Examples of foods and habits that are not good for your thyroid include:

    • Refined grains
    • Simple sugars
    • Soy products
    • Peanuts/peanut products
    • Caffeine
    • Hydrogenated oils
    • Cigarette smoking
    • & Alcohol

    After your doctor assesses the health of your thyroid, they can give you adequate advice on how to address your condition. For anymore advice or information pertaining to your thyroid health and the state of your fertility please contact us!

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