MMR vaccine should be ofered to nonpregnant women of childbearing age who do not have evidence of immunity whenever they make contact with the health-care system. Vaccination of all susceptible hospital personnel who might be exposed to patients with rubella or who might have contact with pregnant women is important. Rubella vaccination should be avoided 1 month before or during pregnancy because the vaccine contains attenuated live virus. No observed evidence links the vaccine and induced malformations, although the overall theoretical risk is up to 2.6 percent (McLean, 2013;
Swamy, 2015). MMR vaccination is not an indication for pregnancy termination.
Prenatal serological screening for rubella is indicated for all pregnant women. Women found to be nonimmune are ofered the MMR vaccine postpartum.
More than 200 antigenically distinct respiratory viruses cause the cominon cold, pharyngitis, laryngitis, bronchitis, and pneumonia. Rhinovirus, coronavirus, and adenovirus are major causes of the common cold. The RNA-containing rhinovirus and coronavirus usually produce a trivial, self-limited illness characterized by rhinorrhea, sneezing, and congestion. he DNA-containing adenovirus is more likely to produce cough and lower respiratory tract involvement, including pneumonia.
The potential teratogenic efects of respiratory viruses are controversial. In a case-control study using data from the Finnish Register of Congenital vlalformations, 393 gravidas with a common cold had a four-to ivefold greater risk of fetal anencephaly (Kurppa, 1991). In another population study of California births from 1989 to 1991, low attributable risks for neural-tube defects were associated with many illnesses in early pregnancy (Shaw, 1998). Adams and colleagues (2012) performed amnionic fluid viral PCR studies in 1191 women undergoing amniocentesis for fetal karyotyping. Viral PCR was positive in 6.5 percent, with adenovirus being the virus most frequently identified. There was an association with fetalgrowth restriction, nonimmune hydrops, foot/hand abnormalities, and neural-tube defects. Adenoviral infection is a known cause of childhood myocarditis. T owbin (1994) and Forsnes (1998) and their associates used PCR tests to identiy and link adenovirus to fetal myocarditis and nonimmune hydrops.
hese RNA viruses are members of the family Bunyaviridae. They are associated with a rodent reservoir, and transmission involves inhalation of virus excreted in rodent urine and feces. Outbreaks of hantaviruses including Sin Nombre virus and Seoul virus have been reported in the United States, the most recent in early 2017 (Centers for Disease Control and Prevention, 2017b). Hantaviruses are a heterogenous group of viruses with low and variable rates of transplacental transmission. Howard and associates (1999) reported the Hantavirus pulmonay syndrome to cause maternal death, fetal demise, and preterm birth. hey found no evidence of vertical transmission of the causative Sin N ombre virus.
hese viruses are a major subgroup of RNA picornaviruses that include coxsackievirus, poliovirus, and echovirus. They are trophic for intestinal epithelium but can also cause widespread maternal, fetal, and neonatal infections that may include the CNS, skin, heart, and lungs. Most maternal infections are subclinical yet can be fatal to the fetus-neonate (Tassin, 2014). Hepatitis A is an enterovirus that is discussed in Chapter 55 (p. 1063).