Diagnosing, managing viral infections in pregnancy a challenge. (Some Expectant Mothers Asymptomatic).

KEY LARGO, FLA. -- Viral infections during pregnancy, such as cytomegalovirus, parvovirus B19, and smallpox, can be clinical challenges to diagnose and manage, Dr. Iffath Abbasi Hoskins said at an ob.gyn. update sponsored by the University of Miami.

* Cytomegalovirus. Although only 1% of pregnant women infected with cytomegalovirus (CMV) transmit the virus to their infants, the outcome can be serious or fatal. Of infected infants, up to one-third will die. Of the survivors, 90% will have sequelae-most often CNS effects and hearing loss," said Dr. Hoskins, executive director of women's services at Memorial Health University Medical Center, Savannah, Georgia.

One of the biggest challenges with CMV is awareness of primary infection during pregnancy because some women do not know they are infected. "Even without evidence or symptoms of infection, the mother will continue to shed the virus, particularly as the pregnancy progresses, she said. In some cases, a neonate who is symptomatic at birth--for example, a preterm infant presenting with pneumonia--is diagnosed before the mother.

Other signs and symptoms of fetal CMV infection include intrauterine growth retardation, jaundice, petechiae, hepatosplenomegaly, and microencephaly. There is no treatment for CMV, so the focus of clinical management is to control the viral shedding during pregnancy.

Viral cultures are commonly used to diagnose CMV infection but do not distinguish primary from recurrent infection. Presence of IgM antibodies in a patient's serum is an indication of active infection within the previous 6 months. A polymerase chain reaction test on amniotic fluid cells taken after 21-22 weeks of gestation is the most reliable test available, Dr. Hoskins said.

The American College of Obstetricians and Gynecologists discourages routine screening for CMV Dr. Hoskins said. "A positive antibody screen is very common because the illness is ubiquitous. Not only is [screening] economically draining, it is also very expensive emotionally for patients and their partners."

* Parvovirus B19. Infection with parvovirus B19, called erythema infectiosum and fifth disease, is also challenging to diagnose. A pregnant woman who is infected may have a fever, rash, arthralgia, or no symptoms. The rate of transplacental transmission is about 30%-50%. Fetal infection occurs in 15%-25% of formerly seronegative women who acquire the infection during ...