[Vertical trasmission of human immunodeficiency virus (HIV) and other sexually transmitted infections (STI)]

Infectious agents which are sexually transmitted determine considerable morbidity in women during the gestational period. Connatal and perinatal infection of the newborn, miscarriage, and low birthweight have all been described. Vertical transmission of HIV and other STD may occur via the placenta during gestation (the major mechanism for syphilis) or at birth during the passage through the cervico-vaginal channel (the major mechanism for HIV, HBV, HSV, gonorrhoea and chlamydia). High serum viral loads of HIV significantly increase the likelihood of newborn infection, while the presence of lesions in the genital tract at birth increases the odd for transmission for HSV. Breast feeding is a well described route of transmission for HIV infection, but it is irrelevant to the transmission of HBV. Cutaneous lesions of the breast and nipples carry a risk of transmission of syphilis and HSV through breast-feeding. Treatment of the etiologic agent is considered an effective means for the prevention of vertical transmission and is recommended for all STI agents except for HBV. HIV infected women on antiretroviral therapy should continue the same treatment regimen if they become pregnant (with the exception of indinavir and efavirenz, which should be replaced as soon as possible); women who did not assume antiretroviral drugs at the time they became pregnant, should start treatment as soon as they reach the second trimester of gestation. Delivery should be performed by elective cesarian section in all HIV infected women. Delivery should also be performed by cesarian section in women who develop a primary HSV infection and have cervico-vaginal lesions. Recurrent episodes of genital herpes are associated to a much lower risk of vertical transmission and do not represent a criterium for cesarian section. Women with documented cervical chlamydia infection should receive a full treatment regimen at the 36th week of gestation. Women with chronic HBV infection do not require etiologic treatment; however, their newborns should receive concomitant doses of HBV immunoglobulins and HBV vaccine soon after birth. Standard practices of prevention of vertical transmission of STI agents applies to women regardless their native country. However, the feasibility of implementation of the guidelines in poor resource countries is a matter of great concern: an unresolved debate is ongoing on optimal strategies for the prevention of vertical transmission of HIV in such countries.