What Is Cryptorchidism?

By BSc, MSc (embryologist) and BA, MA (fertility counselor).
Last Update: 06/30/2015

Cryptorchidism or undescended testicle is a congenital anomaly, that is to say, a birth defect in which one or both testicles do not descend normally during fetus development.

Testicles remain in the abdominal cavity or in the inguinal canal instead of descending to the scrotum, where they should be at birth.

Below you have an index with the 6 points we are going to deal with in this article.


This anomaly is found with a frequency from 3% to 4% in full-term neonates and from 20% to 30% in prematurely born babies. In 80% of cases cryptorchidism is unilateral, i.e. only one testicle is affected and more frequently the left one.

In most cases, the descent of the testicles takes place naturally between the first 6 to 12 months of life.

Cryptorchidism is asymptomatic, the patient will only notice the empty scrotal bag.


Cryptorchidism or hidden testicle may be caused by:

  • An anatomical anomaly like a Gubernaculum anomaly (a ligament of the epididymis where the testicle is inserted).
  • A mechanic obstacle found while the testicle migrates, spermatic vessels or nerves, or if the inguinal canal is very narrow.
  • An obstruction of the scrotum orifice.
  • Hormonal defect or insufficiency, since gonadotropins are needed for a normal development of the genital apparatus.
  • Lack of abdominal pressure.
  • Genetic causes: Prader-Willi syndrome, Kallmann syndrome, etc.


Diagnosis is usually made by palpation of the scrotal bag and, subsequently, of the abdominal zone and the inguinal canal in search of the testicle or testicles. This physical examination is performed at birth or later during a routine check-up.

In 15% of cases, the testicle is difficult to locate and a supplementary test, such as an abdominal ultrasound .has to be performed. If it is not located by this test, the following tests can be made:

  • Ultrasound
  • CT (computed tomography)
  • Magnetic resonance

If the testicles are not detected by means of these tests, surgery may be made, generally a laparoscopy. This surgery is usually performed between the first and the second year of the baby’s life unless it is associated with a hernia. In such case, it would be necessary to operate later.

Risks and complications

The main risks and complications derived from cryptorchidism are:

  • Sterility: for a correct spermatogenesis to take place (sperm cells production), the temperature of testicles must be below body temperature. This is why testicles are located in the scrotal bag at 33ºC. A higher temperature may cause the death of germ cells.
  • Testicular cancer: people who have suffered from cryptorchidism have an increased risk of developing some tumours by atrophy or due to some hormonal imbalance.
  • Inguinal hernia: it can be developed in 65% of cases.
  • Smaller testicular size: due to this anomaly the testicle does not grow in a normal way. Body growth is delayed because the testicle is outside the body.
  • Testicular torsion: the spermatic cord of these children is more predisposed to suffer a torsion and to interrupt the blood supply to the testicle.
  • Psychological effects on adult male


If the testicle does not descend naturally during the first 12 months of life, it will be necessary to resort to a treatment in order to avoid future injuries.

There is a medical treatment with hormones, either beta-hCG or testosterone, that stimulates descent. However, it is falling into disuse because of its side effects.

The surgery, called orchiopexy, is the most effective and mainly used treatment. This surgery is usually performed before the age of two.

There are different studies dealing with the connection between surgery and subsequent fertility and the risk of developing a testicular tumour. In both cases, surgeries that were made at an earlier age had a better prognosis of testicular volume recovery, therefore in adult male fertility, as well as in a smaller risk of having cancer.

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 Teresa Rubio Asensio
Teresa Rubio Asensio
BSc, MSc
Master's Degree in Medicine and Reproductive Genetics from the Miguel Hernández University of Elche (UHM). Teacher of different Clinical Embryology courses at the UHM. Member and writer of scientific contents at ASEBIR and ASPROIN. Embryologist specializing in Assisted Procreation at UR Virgen de la Vega. More information about Teresa Rubio Asensio
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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