Parents often have many questions about their newborn’s health and development. A routine part of a baby’s first physical examination involves checking the testes. This check-up helps ensure proper development and placement. Understanding typical testicular size in newborns can help alleviate common concerns.
Defining Normal Testicular Dimensions
For a full-term newborn, the testes have specific dimensions. The length of a testicle in a 1-4 week old infant ranges between 1.5 to 1.8 centimeters. In terms of volume, a newborn’s testicle is around 1 cubic centimeter (or 1 milliliter) at birth. These measurements are averages, and a slight variation in size between the two testes is normal.
Pediatricians assess testicular size and presence during physical examinations through gentle palpation. Visual inspection also plays a role. Sometimes, an orchidometer, a tool with beads of increasing sizes, is used to estimate testicular volume by comparison.
Factors Influencing Testicular Size
The size of a newborn’s testes can be influenced by developmental factors. Gestational age at birth is a significant determinant, as preterm infants tend to have smaller testes than those born at full term. This difference reflects incomplete development at an earlier birth.
Maternal hormones also play a role in testicular development during pregnancy. After birth, the withdrawal of these hormones can lead to a temporary decrease in testicular size during the first few months of life. This is a normal developmental process as the infant’s own endocrine system adjusts. Testicular volume increases in the first few months before a slight decrease around nine months of age.
Common Variations and When to Consult a Doctor
Parents may notice certain variations in their newborn’s scrotum. A common condition is a hydrocele, a painless swelling due to fluid around the testicle. About 10 percent of newborn infants have a hydrocele, and most cases resolve spontaneously within the first year as the fluid is reabsorbed. Some hydroceles, known as communicating hydroceles, occur when an opening to the abdominal cavity allows fluid to pass into the scrotum.
Another common variation is an undescended testicle, medically termed cryptorchidism. This condition affects approximately 3 percent of full-term male infants and up to 30 percent of premature babies. In many instances, the undescended testicle will descend on its own within the first six months of life. If a testicle has not descended by 6 months to one year of age, a medical consultation is recommended, as treatment can help prevent future complications. Parents should consult a doctor if they cannot feel one or both testes, observe significant swelling or discoloration in the scrotum, or have any other concerns regarding their baby’s testicular health.