Trans-placental spread is least associated with?
HSV infection may be acquired in utero, during the birth process, or during the neonatal period.
Intrauterine and postpartum infections occur infrequently. 
Most cases of neonatal herpes result from maternal infection and transmission, usually during passage through a contaminated infected birth canal of a mother with asymptomatic genital herpes.
HSV
Rubella
HBV
HIV