Effect of serologic status and cesarean delivery on transmission rates of herpes simplex virus from mother to infant.
BACKGROUND
Neonatal herpes most commonly results from fetal exposure to infected maternal genital secretions at the time of delivery. The risk of transmission from mother to infant as it relates to maternal herpes simplex virus (HSV) serologic status and exposure to HSV in the maternal genital tract at the time of labor has not been quantified. Furthermore, no data exist on whether cesarean delivery, the standard of care for women with genital herpes lesions at the time of delivery, reduces HSV transmission.


OBJECTIVE
To determine the effects of viral shedding, maternal HSV serologic status, and delivery route on the risk of transmission of HSV from mother to infant.


METHODS
Prospective cohort of pregnant women enrolled between January 1982 and December 1999.


METHODS
A university medical center, a US Army medical center, and 5 community hospitals in Washington State.


METHODS
A total of 58 362 pregnant women, of whom 40 023 had HSV cultures obtained from the cervix and external genitalia and 31 663 had serum samples tested for HSV.


METHODS
Rates of neonatal HSV infection.


RESULTS
Among the 202 women from whom HSV was isolated at the time of labor, 10 (5%) had neonates with HSV infection (odds ratio [OR], 346; 95% confidence interval [CI], 125-956 for neonatal herpes when HSV was isolated vs not isolated). Cesarean delivery significantly reduced the HSV transmission rate among women from whom HSV was isolated (1 [1.2%] of 85 cesarean vs 9 [7.7%] of 117 vaginal; OR, 0.14; 95% CI, 0.02-1.08; P =.047). Other risk factors for neonatal HSV included first-episode infection (OR, 33.1; 95% CI, 6.5-168), HSV isolation from the cervix (OR, 32.6; 95% CI, 4.1-260), HSV-1 vs HSV-2 isolation at the time of labor (OR, 16.5; 95% CI, 4.1-65), invasive monitoring (OR, 6.8; 95% CI, 1.4-32), delivery before 38 weeks (OR, 4.4; 95% CI, 1.2-16), and maternal age less than 21 years (OR, 4.1; 95% CI, 1.1-15). Neonatal HSV infection rates per 100 000 live births were 54 (95% CI, 19.8-118) among HSV-seronegative women, 26 (95% CI, 9.3-56) among women who were HSV-1-seropositive only, and 22 (95% CI, 4.4-64) among all HSV-2-seropositive women.


CONCLUSIONS
Neonatal HSV infection rates can be reduced by preventing maternal acquisition of genital HSV-1 and HSV-2 infection near term. It can also be reduced by cesarean delivery and limiting the use of invasive monitors among women shedding HSV at the time of labor.
Brown
Zane A
ZA
Department of Obstetrics and Gynecology, University of Washington, Box 356460, Seattle, WA 98195-6460, USA. zbrown@u.washington.edu
Wald
Anna
A
Morrow
R Ashley
RA
Selke
Stacy
S
Zeh
Judith
J
Corey
Lawrence
L
D000914:Antibodies, Viral / Q000097:blood; D002584:Cervix Uteri / Q000821:virology; D002585:Cesarean Section; D036861:Delivery, Obstetric; D005260:Female; D006561:Herpes Simplex / Q000097:blood / Q000151:congenital* / Q000517:prevention & control / Q000635:transmission*; D018259:Herpesvirus 1, Human / Q000302:isolation & purification*; D018258:Herpesvirus 2, Human / Q000302:isolation & purification*; D006801:Humans; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000097:blood / Q000503:physiopathology*; D011446:Prospective Studies; D012307:Risk Factors; D017201:Virus Shedding
D000914:Antibodies, Viral