Most common cause of HIV infection in infant is:

Ans. is a, Perinatal transmissionRef. COGDT 10/e, p 692, 693; Dutta Obs. 7/e, p 301, 302; Harrison 17/e, p 1145; Williams Obs. 23/e, p 1248 onwards, Dutta Obs. 7/e, p 301-302Maternal transmission of HIV to child i.e. vertical transmission can occur:Antepartum (Transplacental)Peripartum (exposure to maternal blood and body fluids at delivery)--Maximum risk periodPostpartum (breastfeeding).Maximum risk of transmission is in peripartum period followed by labour"In the absence of any intervention, an estimated 15-30% of mothers with HIV infection will transmit the infection during pregnancy and delivery, and 10-20% will transmit the infection, through breastfeeding. Vertical transmission of HIV-1 occurs mostly during the intrapartum period (50-70%)" --COGDT 10/e, p 692Note: If the choice is between intrapartum and peripartum period-better option is peripartum as the risk of transmission due to breastfeeding is also included in peripartum period. --Park 19/e, p 289, 290Vertical transmission rate to neonates is [?]14%-25%Factors increasing vertical transmission:Disease factors-Maternal viral load i.e. maternal plasma HIV RNA burden (most important risk factor)-Seroconversion in pregnancy or early disease-Advanced maternal disease-Low CD4 count (i.e. risk of vertical transmission is inversely related to maternal immune status)-Vitamin A deficiency-ChorioamnionitisObstetric factors-Vaginal delivery-Prolonged rupture of membranes (>4 hrs)-Preterm delivery-Chorioamnionitis-Coexistent STD (specially HSV) and syphilitic-Low birth weight infection of placenta-Antepartum invasive procedures (amniocentesis, CVS, etc.)-Intrapartum invasive procedures (instrumental delivery, episiotomy, scalp electrodes, etc.)