What Causes Infertility?

The causes of infertility are varied, yet with the extensive experience and dedication to the field that you’ll find at the New York Fertility Institute, different options and strategies are available for working through most situations. Our  fertility doctors in NYC will help you determine the very best course of treatment to pursue.

Though researchers reveal compelling new insights every year, the worldwide medical community seemingly has yet to learn everything of value there is to know about why some otherwise apparently healthy couples struggle to naturally conceive children.

On average, approximately one in seven couples cannot achieve pregnancy after more than 12 months (or less, if a woman is older than 35) of regular unprotected sex – the general definition of “infertility.” Hope lives on, however. A candid appointment with a reproductive endocrinologist can ease the lingering, unnecessary stigma of shame that often follows infertility and recurrent pregnancy loss, the occurrence of two or more spontaneous miscarriages. Many of these known causes of reproductive difficulty can be not only quickly pinpointed but, in a significant majority of instances, successfully treated. In addition to numerous other factors, infertility often stems from at least one partner’s age, weight, drinking, smoking or miscellaneous lifestyle markers.

Causes Of Female Infertility

Female infertility can be extremely complex in nature with often times multiple causes all working against each other causing fertility problems in women at any age. Below are some of the more common infertility reasons that can be explored during your visit with a fertility doctor.

  • Ovulation Problems
  • Uterine Or Cervical Abnormalities
  • Fallopian Tube Damage Or Blockage
  • Tumor Or Cyst
  • Polycystic Ovary Syndrome (PCOS)
  • Poor Egg Health
  • Uterine Fibroids
  • Ectopic Pregnancy
  • Endometriosis
  • Primary Ovarian Insufficiency (Early Menopause)
  • Pelvic Adhesions
  • Cancer And Its Treatment
  • Genetic Abnormalities
  • Delayed Puberty Or The Absence Of Menstruation (Amenorrhea)
  • Celiac Disease
  • Poorly Controlled Diabetes
  • Some Autoimmune Diseases Such As Lupus
  • Birth Defects
  • “Unexplained” Infertility
  • Lifestyle

Ovulation Problems

Many conditions that prevent a mature egg from releasing as nature intends from an ovary can be traced to hormonal issues. This potential culprit of infertility is most often revealed by an absence of periods or infrequent ones presenting with unusually light or extremely heavy bleeding.

Uterine Or Cervical Abnormalities

Difficulty conceiving often persists due to cervical or uterine abnormalities that either prevent sperm from reaching an egg through the cervical canal or make it difficult for a fertilized oocyte to implant itself in the lining of the uterus due to polyps and fibroids growing in the endometrium.

Fallopian Tube Damage Or Blockage

Around 25 percent of instances of infertility are caused by blocked or damaged fallopian tubes that won’t allow ova to successfully proceed from the ovary to the uterus, often due to ectopic pregnancy, uterine fibroids, endometriosis, pelvic inflammatory disease originating from various sexually transmitted diseases, and several other conditions.

Tumor Or Cyst

Various abnormal growths can impede the natural reproductive functions of a woman’s body in a number of ways, particularly when cysts or tumors develop within the uterus or on the cervix or ovaries. Even benign tumors in the uterine wall can hinder conception by blocking the fallopian tubes.

Polycystic Ovary Syndrome (PCOS)

If you experience irregular menstruation, unusual hair growth, frequent acne and/or pronounced weight gain over an extended time, you may be suffering from a hormonal imbalance caused by numerous small cysts developing on one or both ovaries and preventing the ripening and maturation of one egg per monthly cycle.

Poor Egg Health

If they become fertilized at all, unhealthy eggs that have sustained damage or carry abnormal chromosomes (often due to a woman’s advancing age) frequently cannot result in a term pregnancy and succumb to miscarriage. Causes may range from genetic predisposition, cancer treatment and autoimmune illness to reproductive organ damage, such lifestyle choices as smoking, drinking, diet and exercise, or a number of additional factors.

Uterine Fibroids

Several types of these non-cancerous masses can make pregnancy a virtual impossibility, due to their tendencies to make it difficult for fertilized eggs to implant inside the lining of the uterus. Though there is no clear-cut single causal explanation, there appears to be a strong relationship between development of uterine fibroids and elevated estrogen levels.

Ectopic Pregnancy

Approximately one in 50 pregnancies results in a fertilized egg implanting itself somewhere other than inside the uterine lining, resulting in a potentially dangerous condition known as an ectopic pregnancy. Frequently occurring inside a fallopian tube, treating the misplaced growing embryo often results in ongoing fertility issues, although becoming pregnant later on is not impossible.


Currently affecting more than 7 million American women and often cited as the leading cause of female infertility, endometriosis causes excruciating pain when the endometrial lining of the uterus attaches itself to other organs and cannot be shed from the body during menstruation. Ongoing ovulation and menstruation will continue to aggravate the misplaced lining, causing it to bleed, break down, tear or form scar tissue. Gynecologic surgery is often the only recourse.

Primary Ovarian Insufficiency (Early Menopause)

For often-unknown reasons, some women end menstruation before reaching the age of 40. Factors often associated with early menopause include such genetic conditions as Turner syndrome or carrying Fragile X syndrome, undergoing chemotherapy or radiation treatment, smoking, and several immune system diseases. Whatever the cause, the ovaries simply quit working.

Pelvic Adhesions

In a sense, pelvic adhesions damage a woman’s reproductive system similar to endometriosis. Following such events as appendicitis, pelvic infection or pelvic or abdominal surgery, bands of scar tissue will sometimes bind organs and interfere with their normal functions.

Cancer And Its Treatment

Cancers of the female reproductive system in particular all-too-often severely impact fertility. If the cancer itself doesn’t render a woman infertile, there is still a sizable probability radiation and chemotherapy treatments will critically damage her ovaries or destroy either some or all of her finite natural egg reserves.

Genetic Abnormalities

Heartbreakingly, some women are born with the deck stacked against being able to naturally have children. A number of inherent genetic anomalies can permanently limit or even entirely rule out any chance of a woman becoming pregnant, leaving adoption or surrogacy as the leading alternative paths to parenthood.

Delayed Puberty Or The Absence Of Menstruation (Amenorrhea)

A common side effect of anorexia and exceptionally strenuous exercise among young women is delayed puberty accompanied by amenorrhea, an absence of menstruation lasting at least six months among women who experience regular periods or 12 or more months among those with irregular cycles. Though root causes vary and can include a number of chronic illnesses, this condition is typically associated with significantly decreased body fat.

Celiac Disease

Women diagnosed with Celiac disease who do eventually become pregnant are at an elevated risk of delivering babies with low birth weights and multiple studies have posited that undiagnosed or untreated Celiac disease can cause miscarriage. However, when left unchecked, the condition often results in infertility. Though a single definitive explanation has yet to surface, many doctors suspect this is a consequence of a woman’s body being unable to properly absorb nutrients.

Poorly Controlled Diabetes

Diabetes alone may not necessarily prevent pregnancy, but abnormally high glucose can severely imbalance estrogen, progesterone and testosterone levels and cause miscarriage before a woman is even aware she is pregnant by preventing an embryo from successfully implanting in the uterus. In fact, the chances of miscarriage jolt upward 30 to 60 percent.

Some Autoimmune Diseases Such As Lupus

Several autoimmune diseases such as lupus and psoriasis have been linked to a number of common causes of infertility, including premature ovarian aging (POA), endometriosis, PCOS, and idiopathic infertility, an inability to conceive that has no known explanation. When these diseases send the body’s immune system on a rampage attacking even non-foreign bodies, organs and tissue, the inflamed hostility frequently kills off sperm and embryos in its wake.

Birth Defects

Informing your doctor of any known birth defects in your medical history may paint a clearer picture of your infertility. A pre-existing condition present since infancy can severely damage a woman’s uterus or fallopian tubes by the time she reaches her reproductive years.

“Unexplained” Infertility

For all the complex individual or interlocking reasons a couple may not be able to conceive, physicians ultimately diagnose 15 percent of aspiring parents with infertility that offers no apparent explanation. This possibility presents a bittersweet conclusion: after a battery of tests, nothing is visibly wrong with either partner. Nevertheless, that also leaves no one conclusive avenue to pursue. Some experts might attribute the struggle to become pregnant to some hitherto-unexplored environmental factor, lack of regular exercise or one or both partners being over- over underweight. Ultimately, however, this is a diagnosis of exclusion.


Among the various lifestyle influences that can affect fertility, age is easily the least malleable, especially among women. Reserves of healthy eggs drop off sharply after a woman passes her 35th birthday, but male potency is far from immune to trailing off as the years march onward. However, young and older partners alike can bolster their chances of conceiving by abstaining entirely from drugs and tobacco, sticking to a low-fat balanced diet and consuming alcohol in strict moderation.

Causes Of Male Infertility

While there are many reasons which may exist for male infertility issues, below are some of the more common causes of male infertility compiled for you.

  • Abnormal Sperm Production Or Sperm Health
  • Problems With The Delivery Of Sperm
  • Anti-sperm Antibodies
  • Vas Deferens Blockage
  • Vasectomy Or Failure Of Vasectomy Reversal
  • Environmental Factors
  • Damage Related To Cancer And Its Treatment

Abnormal Sperm Production Or Sperm Health

Naturally, consistent production of healthy sperm plays as vital a role in conception. Conditions such as genetic defects, diabetes, undescended testicles or various infections including HIV, gonorrhea, mumps and chlamydia can all diminish the viability and overall volume of sperm the testes can produce. Enlarged veins in the testes can also prove problematic in this regard.

Problems With The Delivery Of Sperm

Generating optimal sperm in sizable quantities accounts for only half the equation. Other sexual issues such as structural defects, testicular blockages, genital damage, premature ejaculation and genetic diseases like cystic fibrosis can also sabotage proper delivery, further complicating efforts to become pregnant.

Anti-sperm Antibodies

Semen can trigger an unwanted immune response of antibodies that actively seek out and kill sperm. An infected prostate gland, testicular injury or certain surgeries (i.e., biopsy or vasectomy) can cause a man’s immune system to produce organisms that terminate sperm on contact with his own cells, often as a result of the testes no longer being able to protect them as they otherwise naturally would. On the other hand, some women experience allergic reactions to the sperm of their partners and similarly produce these unintended antibodies while experiencing vaginal sores and rashes in addition to painful sexual intercourse.

Vas Deferens Blockage

The vas deferens is the tube through which healthy, fertile sperm are ordinarily channeled. When blocked, they simply cannot exit the body and reach their intended destination. This tube can also malfunction in this fashion due to sexually transmitted diseases including chlamydia and gonorrhea.

Vasectomy Or Failure Of Vasectomy Reversal

Obviously, male infertility is the intended outcome of a vasectomy, the surgical cutting or blocking of the vas deferens. Though it can be reversed in order to restore fertility, a failed reversal will result in continued sterility.

Environmental Factors

As with women, male fertility is subject to an array of environmental risks:

Smoking among male partners has been scientifically associated with increased miscarriage rates, reduced IVF success, lower sperm count and diminished sperm health.

Though the strength of the correlation has never exactly been clear, moderate-to-heavy alcohol consumption has been linked with impotence, lowered sperm quality and dampened libido.

Although reversible, regular prolonged hot tub use can prove detrimental to sperm production.

Some especially strong antibiotics, such as those prescribed to treat urinary tract infections, have been shown to adversely affect sperm counts and motility.

The use of anabolic steroids essentially tricks the body into thinking it no longer has to produce testosterone, eventually taking a toll on its capacity to produce sperm.

Damage Related To Cancer And Its Treatment

Men are also no different from women in the risks cancer and its most effective treatments have on fertility. Testicular and prostate cancers in particular wreak havoc on a man’s reproductive system, but radiation and chemotherapy can also weaken associated organs and eradicate sperm while attacking malignant cells.

Combination Of Both Male & Female

Infertility isn’t always an either-or issue derived from just one partner’s condition. To the contrary, in around 20 to 30 percent of cases, the inability to conceive derives from a combination of both partners’ issues. Although obviously devastating, even this diagnosis can offer hope, depending on which factors are at play. The most promising course of action is to have a frank discussion with your doctor and explore your options accordingly.