Infertility overview

# Overview
Infertility primarily refers to the biological inability of a man or a woman to contribute to conception. It is defined as the failure to conceive after 1 or more years of unprotected sex. Infertility may also refer to the state of a woman who is unable to carry a pregnancy to full term.  There are many biological causes of infertility, some which may be bypassed with medical intervention. Women who are fertile experience a natural period of fertility before and during ovulation, and they are naturally infertile during the rest of the menstrual cycle.  Fertility awareness methods are used to discern when these changes occur; by tracking changes in cervical mucus or basal body temperature.

# Historical perspective
Infertility has always led to social and emotional impairment for the woman involved. In addition, most cultures had their own myths and beliefs around fertility which made it even more challenging for women who could not conceive. The male role in infertility was only brought to light after the discovery of the spermatozoa.

# Classification
Infertility is broadly classified into primary and secondary, where primary infertility is seen in women who have never conceived and secondary infertility is the inability to conceive after a previous pregnancy. Infertility can also be classified based on etiology such as endocrine, metabolic, genetic etc.

# Pathophysiology
Disorders of ovulation make up at least 25% of the cases of infertility worldwide, according to a study done by WHO. Other pathologies such as genital tract infections, pelvic inflammatory disease, endometriosis make up the bulk of female infertility cases.

# Causes
A wide range of physical and emotional factors can cause infertility. Infertility may be due to problems in the woman, man, or both. The most common cause of male infertility is sperm abnormalities such as oligospermia, azoospermia etc. Causes of infertility in females are divided into endocrine, ovarian, tubal, uterine, cervical and other anatomical defects.

# Differentiating Infertility from Other Diseases
There are strict definitions of infertility used by many doctors. However, there are also similar terms, e.g. subfertility for a more benign condition and fecundity for the natural improbability to conceive.

# Epidemiology and demographics
Infertility is more commonly seen in women >35 years of age. Associated conditions such as diabetes mellitus, endometriosis, PCOS also cause infertility in women.

# Risk factors
Old age is the most important non modifiable risk factor determining fertility in women. Other risk factors include being overweight, endocrine disorders such as diabetes mellitus and PCOS. Smoking and drug abuse may also cause infertility.

# Screening
Routine screening for infertility is not usually done, but fertility evaluation is recommended for women who are above 35 years of age and have not already conceived.

# Natural history, Complications and Prognosis
Infertility may cause marital discord among couples who wish to conceive. Infertility treatment such as IVF and AI are associated with risks such as multiple gestations and preterm labour. Prognosis is generally good in women who receive treatment for infertility.

# Diagnosis
Diagnosis of infertility usually involves a battery of tests including blood and urine tests along with radiographic imaging. Hormone levels are checked via blood and urine tests whereas patency and abnormalities in the genital tract are detected with hysteroscopy, hysterosalpingography and gynecologic ultrasonography.

# Treatment

## Medical Therapy
Treatment of infertility usually starts with medication. In vitro fertilization (IVF) in addition to various forms and developments of it (ICSI, ZIFT, GIFT) is another solution. All these come under the gamut of assisted reproductive technology. They all include that the fertilization takes place outside the body. On the other hand, an insemination can make a fertilization inside the body. Other techniques are assisted hatching and PGD.

## Surgical therapy
Surgical therapy mainly aims at resolving any anatomical defects in the genital tract. Tuboplasty is done for any defects in the fallopian tubes such as scarring due to pelvic inflammatory disease or tuberculosis. When fibroids are the cause of infertility, myomectomy can be done. Other surgical methods include metroplasty, polypectomy, adhesiolysis.

# Primary Prevention