Common Causes of Infertility

A doctor describing common causes of infertility with her hands

Polycystic Ovarian Syndrome (PCOS)

PCOS is one of the most common causes of irregular menstrual cycles and infertility. In individuals with PCOS, the eggs fail to mature and ovulate, and the ovaries usually have a distinctive appearance on ultrasound.


Other symptoms associated with PCOS are acne, oily skin, excessive hair growth (hirsutism) and pattern thinning of the hair. Some people are also overweight or obese. 


Tests for PCOS include:

  • Blood hormone testing
  • Transvaginal ultrasound


Treatment options 

The first approach to treating PCOS should be changes in lifestyle, including a low carbohydrate diet to help control insulin levels, regular exercise, and weight loss if you have a BMI over 25. Sometimes just these lifestyle changes are enough to normalize your menstrual cycles and restore ovulation. 

You might also be given one of several drugs to stimulate egg production like Clomid, Letrozole, or injectable FSH. Alternatively, you might be given Metformin and/or the supplement myo-inositol to help lower your insulin levels and regularize your cycle.

Fallopian Tube Blockage

You need to have open and functioning Fallopian tubes for the sperm and the egg to meet and for natural fertilization to occur. Scarring or blockage in your Fallopian tubes can prevent the sperm from reaching the egg. Infections like chlamydia, gonorrhea, or pelvic inflammatory disease are common causes of blocked Fallopian tubes.


Tests for Fallopian tube blockage include:

  • A detailed history and examination of your uterus and Fallopian tubes with a special X-ray called a hysterosalpingogram (HSG)
  • Possibly a laparoscopy.


Treatment options 

Sometimes minor surgery like tubal cannulation or a laparoscopy can repair blocked or damaged tubes. If that is not possible IVF is an option.

Thyroid Disease

Your thyroid is a gland in your neck which produces many hormones including hormones necessary for successful pregnancy. Both an overactive thyroid (hyperthyroid) and an under-active thyroid (hypothyroid) can cause problems with conception by disrupting ovulation or disturbing the hormonal balance of the uterus. Sometimes miscarriages are linked to thyroid dysfunction.


Tests for thyroid disease include:

  • Blood tests for thyroid stimulating hormone (TSH and thyroid antibodies)


Treatment options

If your thyroid activity is too low, you will typically be treated with an oral medication which is a synthetic form of your natural thyroid hormone (e.g., Synthroid). If your thyroid activity is too high, you will be referred to a specialist in endocrinology for further tests and treatment. 

New information suggests that tight thyroid control through fertility treatments and pregnancy might reduce miscarriage and perhaps help with the neurodevelopment of the fetus.


Up to 10% of women may have some degree of endometriosis associated with pelvic pain and infertility. The condition causes inflammation in the Fallopian tubes and ovaries, producing scar tissue. If you have endometriosis, you may have pelvic pain that is worse when you menstruate and during intercourse.


Tests for Endometriosis include:

  • Transvaginal ultrasound
  • Laparoscopy


You may also be asked to keep a symptom diary.


Treatment options

If your endometriosis is relatively mild, more conservative treatments, such as a laparoscopy, may be options. However, in most cases, in vitro fertilization (IVF) offers you the best chance of getting pregnant. You can also receive separate treatment for any pain the endometriosis may be causing you.

Primary Ovarian Insufficiency

Although most women experience menopause around the age of 50, some stop menstruating at a younger age. This occurs in about 10% of women under 40 and 1% under 30. If you have had no menstrual flow for over a year, you may be checked for Primary Ovarian Insufficiency (POI). Women with POI have lost eggs at a greater than expected rate. Sometimes this condition is associated with autoimmune disease. 


Tests for POI include:

  • Blood tests (hormonal, genetic, and other tests)
  • Transvaginal ultrasound


Treatment options

If you have POI, your chances of getting pregnant naturally or with IVF using your own eggs are quite low. However, your chance of getting pregnant with donor eggs in an IVF cycle is excellent with an up to 80% success rate. Even though there is no medical treatment for POI about 5% to 10% of women with POI go on to conceive without medical intervention.

Recurrent Pregnancy Loss (RPL)

Many women experience at least one miscarriage. If you have had one or two miscarriages, it will not normally affect your chances of carrying the next baby to term. 

Some people, however, experience repetitive, consecutive miscarriages known as recurrent pregnancy loss (RPL). Recurrent pregnancy loss can be devastating, but it is important to remember that even if you have had multiple miscarriages, you still have a very good chance of eventually having a healthy pregnancy. In some cases, a cause can be identified and measures to taken to prevent future miscarriages.


Tests for RPL include:

  • A comprehensive evaluation (as there are various reasons why RPL might occur) including blood tests (hormones, blood clotting proteins, chromosome analysis) and imaging of the uterus (usually a hysteroscopy).
  • The sperm producing partner may also require testing, including blood test for chromosomal analysis. 


For at least 50% of women with RPL, a cause for miscarriage will not be found.


Treatment options 

If a cause for RPL is identified, treatment is targeted to the specific cause. This may include various medications, surgery, or genetic testing of embryos (PGT-A). If a cause for RPL is not found, your physician will discuss the best approach towards achieving a healthy pregnancy.

Unexplained Infertility

Unexplained infertility occurs in about 15% of couples and individuals trying to conceive. It doesn’t mean there is no reason for your infertility, it just means that we can’t identify the cause with any of our current testing. 


The good news is that even though we can’t determine what is preventing you from getting pregnant, we can still help you achieve a pregnancy. 


There are several treatments for unexplained infertility including:

  • Fertility drugs such as clomiphene citrate, or follicle-stimulating hormone (FSH)
  • Intrauterine insemination (IUI) (artificial insemination of sperm into the uterus)
  • In vitro fertilization (IVF)

Sperm Issues

Sperm issues account for approximately 40% of infertility. There are several heath and lifestyle factors that could be affecting the quantity and health of your sperm. 


Tests include:

  • A semen analysis to determine your sperm quantity and quality 


Treatment options 

If you are having sperm issues, eliminating lifestyle factors like smoking, excess alcohol, and recreational drugs like marijuana and maintaining a healthy BMI and taking a multivitamin with antioxidants may improve sperm parameters and allow you to conceive naturally. 

Assisted reproduction, such as IUI or IVF-ICSI can help in situations when you are not able to conceive naturally. In some instances, extraction of sperm directly from the testicles is necessary. This would be reviewed by your specialist.

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