Prevalence of viral DNA in amniotic fluid of low-risk pregnancies in the second trimester.
OBJECTIVE
The association between fetal viral infection and adverse pregnancy outcome is well documented. However, the prevalence of common viral pathogens in the amniotic fluid of normal pregnancies is not established. The purpose of this study was to determine this prevalence in asymptomatic patients.


METHODS
This was a prospective observational study of patients at low risk for viral infection who were referred for second-trimester genetic amniocentesis. In patients with normal fetal anatomy on ultrasound and a normal fetal karyotype, a 2-ml aliquot of amniotic fluid obtained at amniocentesis was analyzed by multiplex polymerase chain reaction for cytomegalovirus (CMV), parvovirus B19, adenovirus, enterovirus, herpes simplex virus (HSV), respiratory syncytial virus (RSV) and Epstein-Barr virus (EBV).


RESULTS
Among 686 patients, advanced maternal age was the most common indication for genetic testing (n = 469, 68.4%), followed by elevated aneuploidy risk on triple screen (n = 164, 23.9%), elevated maternal serum alpha-fetoprotein (n = 20, 2.9%), previous aneuploidy (n = 16, 2.3%) and family history of inheritable disease (n = 14, 2.1%). Forty-four (6.4%) amniotic fluid samples were positive for viral genome. A single genome was amplified in 41 samples (93%). In three samples, two viral genomes were identified. Adenovirus was most frequently identified (37/44), followed by CMV (5/44), EBV (2/44), enterovirus (2/44) and RSV (1/44). Parvovirus and HSV were not identified. There was a bimodal seasonal variation in prevalence, with the highest prevalence during the summer and late winter.


CONCLUSIONS
Viral genome is commonly found in amniotic fluid with a sonographically normal fetus, and the prevalence follows a seasonal pattern. The mechanism, significance and effects of this asymptomatic viral presence require further study.
Baschat
A A
AA
Center for Advanced Fetal Care, Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland, Baltimore, Maryland 21201-1703, USA.
Towbin
J
J
Bowles
N E
NE
Harman
C R
CR
Weiner
C P
CP
D000256:Adenoviridae / Q000302:isolation & purification*; D000328:Adult; D000649:Amniocentesis; D000653:Amniotic Fluid / Q000821:virology*; D000782:Aneuploidy; D000013:Congenital Abnormalities / Q000000981:diagnostic imaging / Q000235:genetics; D003587:Cytomegalovirus / Q000302:isolation & purification*; D004279:DNA, Viral / Q000032:analysis*; D004770:Enterovirus / Q000302:isolation & purification*; D005260:Female; D020022:Genetic Predisposition to Disease; D005820:Genetic Testing / Q000379:methods; D004854:Herpesvirus 4, Human / Q000302:isolation & purification*; D006801:Humans; D008423:Maternal Age; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D018566:Pregnancy, High-Risk; D015995:Prevalence; D011446:Prospective Studies; D012136:Respiratory Syncytial Viruses / Q000302:isolation & purification*; D012621:Seasons; D016216:Ultrasonography, Prenatal; D000509:alpha-Fetoproteins / Q000032:analysis
D004279:DNA, Viral; D000509:alpha-Fetoproteins