<prompt> HIV transmission is maximum during?During Caeserian sectionDuring antepartum periodDuring vaginal deliveryBreast feeding  <response>: Ans. C. During vaginal delivery Ref. Textbook of Gynaecology by D C Dutta 5thpg. 538; Dutta obstetrics 7thpg. 302.Textbook of Gynaecology b D C Dutta 5tjLpg. 149...under the heading Mode of transmission of HIV subheading Perinatal transmission...:Perinatal transmission-the vertical transmission to neonates of the infected mothers is 25-35 . The baby may be affected in utero 30 through transaplacental transfer, during delivery 70-75 by contaminated secretions and blood of birth canal and through breast milk in neonatal period 10-20. Mothers who are HIV infected can pass the virus on to their fetuses in utero or to infants via breast milk. Vaginal delivery is the most common and most effective mode of transmission. Exposures, which increase the risk of mother-to-child transmission, include -- Vaginal delivery,- Preterm delivery,- Maternal bleeding, and- Trauma to the fetal skin. In the absence of prophylactic antiretroviral therapy to the mother during pregnancy, labor, and delivery, and to the fetus following birth, the probability of transmission of HIV from mother to infantfetus ranges from 15 to 25 in industrialized and from 25 to 35 in developing countries. 