transmission in utero (congenital infection) (5%), or while passing through an infected birth canal (intrapartum) (85%), or from contact with infected oral secretions (postpartum) (10%) Maternal HSV infection can be described as first-episode primary infection, first-episode nonprimary infection, and recurrent infection First-episode primary infections occur in mothers who have never been previously exposed to infection First-episode nonprimary infections occur when a mother has had HSV-1 previously and then becomes infected with HSV-2 (or vice versa) since HSV-1 and HSV-2 share significant cross reactivity Recurrent maternal infection implies that the mother has had a previous exposure and has formed protective antibodies that are conveyed to the baby but is having a reactivation Recurrent infections are responsible for 50% of the cases of neonatal HSV because recurrent maternal outbreaks occur more commonly than primary infections However, primary infections are more severe in nature than recurrent episodes due to the absence of maternal antibodies and shedding of higher quantities of HSV for longer periods of time About 30% of pregnant women will have serologic evidence of HSV-2, the majority without prior history of symptoms or infection Complete perinatal history may reveal the occurrence of genital outbreaks before or shortly after birth History of contact with a person who has had cold sores or presence of breast lesions in breast-feeding mothers may be helpful Maternal history of a genital infection is often unclear due to the possibility of asymptomatic or subclinical infections It is estimated that 60% to 80% of women whose infants develop HSV not have a prior history of genital infection or symptoms Mothers with a history of recurrent HSV infection have a 2% chance of transmitting infection to their newborn at delivery during active shedding The chance of transmission increases to 57% in first-episode primary maternal infection and 25% in first-episode nonprimary infection History may also reveal the presence of risk factors such as a primary infection, vaginal delivery, prolonged rupture of membranes (>4 to hours), use of fetal scalp electrode, or disruption of the skin during vacuum extraction HSV disease in neonates is usually symptomatic It can present in two forms: (a) Congenital HSV infection from an in utero transmission (characterized by vesicular skin lesions, or scarring, neurologic lesions [microcephaly, hydranencephaly, intracranial calcifications, hypertonicity, or seizures] and ocular findings [chorioretinitis, microphthalmia, cataracts, or optic atrophy]) or (b) neonatal HSV, which may present to weeks after discharge from the newborn nursery