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Acyclovir in pregnancy for primary prevention of neonatal herpes

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Randolph AG, Hartshorn RM, Washington AE
Acyclovir prophylaxis in late pregnancy to prevent neonatal herpes: A cost-effectiveness analysis.
Obstet Gynecol 1996;88:603-10.
Reviewed by
Michael N. Stiffman, M.D., M.S.P.H. and Patricia Adam, M.D., M.S.P.H.

Clinical question

Is the administration of oral acyclovir to pregnant women with recurrent herpes cost effective for preventing neonatal herpes?


Up to one third of all pregnant women have been exposed to herpes and may be at risk for transmitting the infection during childbirth. The current standard of care in many hospitals is a cesarean section for active herpes lesions present during labor. Recent evidence suggests that acyclovir late in pregnancy may decrease the frequency of recurrent active lesions. This analysis incorporates this new evidence and reassesses the data supporting the current standard of care.

Population studied

The study population consisted of a hypothetical cohort of 10,000 pregnant women at 37 weeks gestation with at least one previous clinically documented episode of genital herpes.

Study design and validity

This well designed cost-effectiveness analysis looked at four main strategies in the decision tree: A) no drug treatment but cesarean section if active herpes lesions are present at the time of delivery, B) acyclovir prophylaxis from 37 weeks and cesarean section if active lesions are present, C) acyclovir prophylaxis and vaginal delivery even if active herpes lesions are present, and D) no intervention. The decision tree considered all important outcomes, including long term costs and sequelae of neurologic damage from neonatal herpes. The evidence for all probabilities in the tree was presented and referenced. The estimates of acyclovir's benefit were based on two randomized controlled trials that evaluated its effect on prevention of active herpes lesions. Extrapolation was then made to an effect on prevention of neonatal herpes. The estimates of the benefits of cesarean section were based only on expert opinion. The authors acknowledge that there are no data to support this opinion. Appropriate sensitivity analyses (varying the probability of each intermediate step through a range of possibilities) were presented. Viral resistance was not considered in the analysis. It would be helpful to know how increasing levels of resistance would affect the analysis.

Outcomes measured

Primary outcomes measured were the frequency of infections, morbidity and mortality, the direct cost per neonatal life saved, and the direct cost for prevention of long term neurologic sequelae associated with each strategy.


In this analysis, the use of acyclovir is clearly beneficial. Cesarean section appears beneficial but the true effect is unknown because the data are inadequate. The rate of neonatal infection per 10,000 women followed for each of the four strategies listed above is: A) no drug/cesarean, 3.4; B) acyclovir/cesarean, 0.7; C) acyclovir/no cesarean, 1.2; and D) no drug/no cesarean, 6.2. Costs for each case of neonatal herpes prevented (compared to strategy D) are $1,319,457 for strategy A; $493,641 for strategy B; and $400,382 for strategy C. Costs per case of neonatal death or disability prevented are $3,012,459 for strategy A; $1,127,034 for strategy B; and $914,114 for strategy C.

Recommendations for clinical practice

A policy of routine drug prophylaxis for pregnant women with recurrent genital herpes is cost effective. The evidence for the effectiveness of acyclovir is based on trials looking at intermediate outcomes. Thus, the true effectiveness of acyclovir on neonatal infection may be greater because (theoretically) acyclovir may decrease the viral load present in active lesions and reduce the transmission rate. Acyclovir is currently not approved for use in pregnant women. Assuming that it is proven safe for use in the third trimester, providers should offer prophylactic acyclovir to pregnant women with a history of genital herpes. The data are too weak to make a strong recommendation for or against prophylactic cesarean section. Until more definitive patient-oriented evidence is available, the decision to use acyclovir prophylaxis and/or to perform a cesarean section remains a matter of informed consent.

This Web page is referenced from another page containing related information about Herpes


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