Congenital Infections

Neal P. Simon, M.D.

What is a Congenital Infection?

Congenital infections affect the unborn fetus or newborn infant.   They are generally caused by viruses that may be picked up by the baby at any time during the pregnancy up through the time of delivery.  The viruses initially infect the mother who subsequently may pass it to the baby either directly through the placenta or at the time of delivery as the baby passes through the birth canal.

Mothers generally do not feel sick with the viruses.  Sometimes they have flu-like symptoms.  Even if the mother is known to have a viral illness during her pregnancy, her immune system may prevent the virus from infecting the fetus or newborn infant.

The more common viruses linked to congenital infections include the Cytomegalovirus (CMV), Herpes, Rubella (German measles), Parvovirus, Varicella (chickenpox), and Enteroviruses.

How Do I Know If My Baby Has a Congenital Infection?

This can be very difficult initially.  Most congenital infections in the fetus and newborn baby are totally silent and asymptomatic.   However, some may be serious and cause profound damage to the body resulting in birth defects or even death. Even if the infection is silent initially, it can quietly and slowly damage the body, causing medical and developmental problems that only show up months or even years later.

Diagnosis of a congenital infection can sometimes be made by the obstetrician or pediatrician based upon the mother’s symptoms, the baby’s physical findings before (by ultrasound) or after birth, as well as by blood tests on both mother and baby.  Sometimes, in spite of a complicated medical workup, a congenital infection cannot be proven.

What Medical Complications are Associated with Congenital Infection?

Calcifications in the brain associated with brain damage may be seen with CMV infections.  The brain grows poorly and the head subsequently appears small (microcephaly).  Hydrocephalus ("water on the brain") and groin hernias may also occur.  Diabetes mellitus and heart problems can be seen with congenital Rubella infections.  Recurrent eye and skin infections are typical for Herpes.

What Developmental Complications are Associated with Congenital Infections?

Babies with congenital infections may suffer particular damage to the developing brain and sensory organs. The subsequent effects of the infection are quite diverse, resulting in a broad range of developmental outcomes.

Hearing loss is the most common developmental disability, especially from CMV and Rubella infections.  It may be present at birth or develop later in childhood and be progressive.  Hearing loss may be difficult to detect in infancy.

Visual impairments are common, especially with Herpes and Rubella infections.  The impairments result from the development of cataracts or from actual destruction of the tissues of the eye.

Mild to severe brain damage may occur, resulting in various degrees of mental retardation, learning and behavioral disorders, and autism.  Special education is frequently required.

What Can I Do After My Baby Goes Home?

Babies born with an obvious congenital infection will frequently exhibit a serious developmental disability early in life.  Babies born with silent congenital infections may not exhibit disabilities for months or years.  For this reason, it is important that all babies born with known or suspected congenital infections be followed closely to detect signs of developmental problems at the earliest possible age.  Early vision and hearing screens are particularly important.  Close, early follow-up will permit the introduction of necessary interventional therapies at the earliest time possible.