From the Guidelines
There is an association between genital herpes and preterm birth, as evidenced by a trial showing decreased risk of preterm birth with suppressive acyclovir therapy starting at 28 weeks' gestation 1. The relationship between genital herpes and preterm birth is complex, with various factors influencing the risk. Women with a history of genital herpes have a decreased risk of viral shedding, recurrences, and cesarean deliveries when given suppressive antiviral therapy, such as acyclovir 400 mg TID or valacyclovir 500 mg BID, starting at 36 weeks' gestational age 1. Key findings from recent studies include:
- A trial of 200 HSV-2–seropositive, HIV-seronegative women in Uganda randomized to receive acyclovir 400 mg BID or placebo starting at 28 weeks' gestation showed decreased risk of preterm birth and a trend toward decreased risk of premature rupture of membranes at 36 weeks among the acyclovir group 1.
- The American College of Obstetrics and Gynecology recommends against routine screening for HSV serostatus during pregnancy based on a lack of evidence for cost-effectiveness 1. To reduce the risk of preterm birth associated with genital herpes, suppressive antiviral therapy, such as acyclovir 400 mg BID, may be considered starting at 28 weeks' gestation for women with HSV-2 infection 1. However, additional data are needed to replicate this finding among a larger sample size.
From the Research
Association Between Genital Herpes and Preterm Birth
- There is evidence to suggest an association between genital herpes and preterm birth, particularly if the infection is left untreated 2, 3.
- A study published in 2019 found that women with untreated genital herpes had a modest increased risk of spontaneous preterm birth (sPTB), with an odds ratio (OR) of 1.22 [1.14,1.32] 2.
- Another study published in 2014 found that having untreated genital herpes during the first or second trimester was associated with more than double the risk of preterm delivery (PTD), with an OR of 2.23 [1.80,2.76] 3.
- In contrast, undergoing antiherpes treatment during pregnancy was associated with a lower risk of PTD, with an OR of 1.11 [0.89,1.38] 3.
Effect of Antiviral Treatment on Preterm Birth
- Antiviral treatment has been shown to reduce the risk of preterm birth in women with genital herpes 2, 3.
- A study published in 2019 found that women with treated genital herpes had an OR of 0.91 [0.85,0.98] for sPTB, indicating a reduced risk of preterm birth 2.
- Another study published in 2014 found that antiherpes treatment during pregnancy was associated with a lower risk of PTD, with an OR of 1.11 [0.89,1.38] 3.
Prevention of Neonatal Herpes
- Prevention of neonatal herpes depends on preventing acquisition of genital HSV infection during late pregnancy and avoiding exposure of the infant to herpetic lesions during delivery 4, 5.
- Elective cesarean section before the onset of labor is the choice mode of delivery for women with genital lesions or with prodromal symptoms near the term, even if it offers only a partial protection against neonatal infection 4, 5.
- Antiviral suppressive therapy is used from 36 weeks of gestation until delivery in pregnant women with recurrences to prevent genital lesions at the time of labor so reducing the need of caesarean sections 6, 5.