In the US, 2% of women make genital herpes during pregnancy, and 25-65% of pregnant women have genital infection with HSV1 or HSV2. Several studies reported an incidence of neonatal herpes of 8, 12, 31, 60 cases to 100,000 births and about 1500 new cases annually.
Corey L, Wald A. Maternal and Neonatal Herpes Simplex Virus infections. N Engl J Med 2009; 361:1376-1385.
The risk of transmission to the foetus is significantly higher in the case of women who acquire HSV1 or HSV2 infection during pregnancy compared to those who have a chronic infection that reactivates at birth, 25-50% vs. < 1%. Therefore, 50-80% of cases of neonatal herpes are derived from mothers who are infected during pregnancy, toward its end.
Corey L, Wald A. Maternal and Neonatal Herpes Simplex Virus infections. N Engl J Med 2009; 361:1376-1385.
The real number of people infected with HSV is much higher than those diagnosed precisely due to the existence in a high proportion of the asymptomatic infected persons.
The transmission of the infection to the fetus depends on the type of maternal infection; this distinguishes several situations encountered in medical practice with different frequencies.
Riscul de herpes neonatal în funcție de statusul mamei (după Hurraux)
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Vlădăreanu R. Medical conditions associated with pregnancy. Ed. Infomedica, Bucharest, 1999, p. 279.
If prepartum (or a month before) occurs primoinfection or a recurrence, protocol is to be performed caesarean.
Neonatal herpes is a major perinatal problem. Since 50% of newborns, to whom the infection was confirmed by obtaining cultures, do not have typical lesions on the skin or mucous membranes the estimation of the frequency of this disease is subject to errors.
Most neonatal herpes infections occur by contact of the fetus with maternal secretions during the crossing of the genital tract.
It is estimated that 70-85% of neonatal HSV is caused by HSV2, but the newborn can be infected even with HSV1, which accounts for approximately 1/3 of the etiology of genital herpes infections. HSV2 infection has a worse prognosis than HSV1.
Congenital herpes defined as a prenatal infection of the fetus with HSV2 is extremely rare and frequently occurs with the death of the fetus in the uterus. Those who survive have the following manifestations: vesicular eruption, ocular disorders (corioretinitis, microphthalmia, cataract), neurological disorders (cerebral calcification, microcephaly, convulsions, encephalomalacia), failure of growth, disorders in the psychomotor development.
In a 2003 study, based on 202 pregnant women who were infected with HSV at the time of birth, the conclusion is that in 10% of newborns the infection was transmitted. The rate of transmission was much lower in the case of Caesarean birth (1.2%) compared to vaginal childbirth (7.7%).
(Brown ZA, Wald A, Morrow RA, Hedersleben S, Zeh J, Corey L. Effect of serological status and cesarean delivery on transmission rates of herpes simplex virus from mother to infant. Jama. 2003 Jan 8; 289 (2): 203).
Studies of 2009 place the risk of neonatal infection as varying between 30-50% in the case of HSV infections that are acquired in the last trimester of pregnancy and is 1% in the early stages of pregnancy. About 85% of perinatal infections are acquired during the intrapartum period.
(Anzivino E, Fioriti D, Mischitelli M, Bellizzi A, Barucca V, Chiarini F, Pietropaolo v. Herpes simplex virus infection in pregnancy and in neon: status of Art of epidemiology, diagnosis, therapy and prevention. Virology Journal. 2009 APR 6; 6 (1): 1).
In a more recent study, which included 50 newborns with HSV, a 26% fatality risk was observed. It was observed that in all 13 cases where children died, mothers did not present active herpes lesions at the time of birth, and only 8 pregnant women presented a risk factor for herpes infection
(Lopez-Medina E, Cantey JB, Sánchez PJ. The mortality of neonatal herpes simplex virus infection. The Journal of Pediatrics. 2015 Jun 30; 166 (6): 1529-32).
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