The risk of transmission from mother to baby is highest if the mother becomes infected at around the time of delivery (transmission risk 30 to 60%), but the risk falls to 3% if it is a recurrent infection, and is less than 1% if there are no visible lesions. To prevent neonatal infections, seronegative women are recommended to avoid unprotected oral-genital contact with an HSV-1 seropositive partner and conventional sex with a partner having a genital infection during the last trimester of pregnancy. A seronegative mother that contracts HSV at this time has up to a 57% chance of conveying the infection to her baby during childbirth, since insufficient time will have occurred for the generation and transfer of protective maternal antibodies before the birth of the child, whereas a woman seropositive for both HSV-1 and HSV-2 has around a 1-3% chance of transmitting infection to her infant. HSV-1 being transmitted by oral sex as HSV-2 is not very common but there is always the risk  Women that are seropositive for only one type of HSV are only half as likely to transmit HSV as infected seronegative mothers. Mothers infected with HSV are advised to avoid procedures that would cause trauma to the infant during birth (e.g., fetal scalp electrodes, forceps, and vacuum extractors) and, should lesions be present, to elect caesarean section to reduce exposure of the child to infected secretions in the birth canal. The use of antiviral treatments, such as aciclovir, given from the 36th week of pregnancy limits HSV recurrence and shedding during childbirth, thereby reducing the need for caesarean section.