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Micropenis

What is micropenis?

Micropenis is defined as a normally structured penis that is below the normal size range for an infant. Normally, the length of a newborn boy's penis is between 2.8 to 4.2 centimeters (1.1 to 1.6 inches) with a circumference of 0.9 to 1.3 centimeters (0.35 to 0.5 inches). This measurement is taken by carefully stretching the penis and measuring from the tip of the penis to the base of the penis. A penis length of less than 1.9 centimeters (0.75 inches) is usually considered micropenis.

What causes micropenis?

Micropenis can happen alone, but usually happens along with other disorders. Hormone disorders that cause an abnormal level of the hormones involved in the development of the sexual organs may be seen in combination with micropenis. This can involve the pituitary gland or the hypothalamus.

What are the symptoms of micropenis?

The most common finding with micropenis is an infant penis size that is less than 1.9 centimeters when stretched gently. In some cases, low sperm count, resulting in infertility or decreased fertility, is found in adulthood. Micropenis may or may not be seen along with other disorders. Always talk with your child's healthcare provider for a diagnosis.

How is micropenis diagnosed?

Diagnosis is usually made by physical exam. Your child may then be referred to several specialists including a pediatric urologist (a healthcare provider who specializes in disorders and care of the urinary tract and the male genital tract) and a pediatric endocrinologist (a healthcare provider who specializes in hormones).

What is the treatment for micropenis?

Your baby’s healthcare provider will figure out the best treatment for your baby based on:

  • How old your baby is

  • His or her overall health and past health

  • How sick he or she is

  • How well your baby can handle specific medicines, procedures, or therapies

  • How long the condition is expected to last

  • Your opinion or preference

There is no cure for micropenis. Hormone therapy may be used for some children to stimulate penile growth. Other treatment choices will be discussed with you.

Medical Reviewers:

  • Adler, Liora C., MD
  • Finke, Amy, RN, BSN