Fetal Hernia/Hydrocele

An inguinal hernia occurs when, during fetal development, a sac surrounding an infant's normally descending sexual organs (for boys, the testicles into the scrotum and for girls, the uterine ligament into the groin area) does not close as tightly as it should, allowing a portion of the intestine to bulge through the sac's channel-like opening. Normally the sac closes completely during the ninth month of intrauterine life or soon after birth.

When fluid collects in a baby boy's scrotum due to the same inadequate closure of the sac from the abdominal cavity, the condition in known as a hydrocele. Hydroceles are generally not harmful to the testicles and do not cause pain to the baby.

How Common Are Fetal Hernias/Hydroceles?

Hernias and hydroceles are among the most common of all pediatric surgical problems. Premature infants have a higher incidence than full-term babies, and boys more than girls.

What Causes a Fetal Hernia/Hydrocele?

Some hernias and hydroceles seem to run in families, but true hereditary factors have not been identified.

What Are the Symptoms of a Fetal Hernia/Hydrocele?

A bulge (swelling) in the groin, which at times may extend into the scrotum, is by far the most frequent sign. The bulge may appear and then disappear with some regularity, especially during straining, crying or coughing.

Although sharp pain is usually not associated with herniation, discomfort that occurs in some babies is easily overlooked. Occasionally constipation, "colicky baby" syndrome and even regurgitation are present.

In a very young baby, the initial presentation may represent more severe problems. The baby's bulge is firm and tender to touch, the groin and scrotum may be reddened, and the infant may be vomiting or feeding poorly. A history of recurring groin swelling that the parents or the pediatrician can reduce (gently pushing the organs back into place) is a strong indication that a hernia is present.

How Is a Fetal Hernia/Hydrocele Diagnosed?

A fetal hydrocele can be diagnosed by ultrasound (sonogram) examination before birth. Evaluation of the urinary system is now part of the routine ultrasound examination done by many obstetricians as part of their routine prenatal care. Hydroceles are most commonly identified in the third trimester and occur in approximately 15% of all male fetuses.

After the baby is born, only observation is necessary to make the diagnosis. Diagnostic confirmation is made when the contents of the hernia can be reduced (gently pushed back into place). Hydroceles are difficult to reduce manually, although many reduce spontaneously when the child is kept lying on his back for several hours.

If the hernia is not clearly evident during the examination, but the parents have observed it, repeated examination in two to three weeks is recommended. The parents should continue observation, be taught how to reduce the hernia and, at times, even resort to photographing the hernia so that a definite diagnosis can be established. If the hernia cannot be reduced, it is known as an incarcerated (or irreducible).

Ultrasound can be used to distinguish between a hydrocele and a hernia when the physical exam is inconclusive.

How Is a Fetal Hernia/Hydrocele Treated?

The reason for repairing an inguinal hernia is to prevent incarceration. The younger the patient, the sooner the repair should happen. Premature babies should have their hernias repaired just before discharge from the hospital. Asymptomatic school-age children can be repaired when school is in recess. 

The timing of repair is less clear with hydroceles. In most centers, hydroceles are not repaired until the baby is 12 to 18 months or older. Approximately 90–95 percent of all hydroceles resolve spontaneously in the first few months of life. If a hydrocele becomes very large and tense, earlier repair may be considered. If a hydrocele cannot be differentiated from a hernia, an operation is indicated.

Typically, the surgery is an outpatient procedure performed under general anesthesia. But premature infants and children with medical conditions, such as cystic fibrosis or hemophilia, usually need admission for 24 hours of observation.

Postoperative Care

Postoperative care is straightforward. Since absorbable sutures are used for wound closure, most of the children can be bathed within 24 to 48 hours. There are no restrictions on diet or activities. Tylenol for analgesia is all that is required. In older children, sometimes ibuprofen or codeine may be necessary.


Recurrent herniation is rare and occurs in less than 1 percent of cases. More often, residual or post-traumatic hydroceles may be noted. If these do not go away after several months, it might be helpful to examine their contents.