<prompt> The maximum chances of HIV infection being transmitted to the fetus infant in an HIV infected mother are during:First trimesterSecond trimesterPeripaumDuring breastfeeding  <response>: Veical transmission of HIV out of total 100 before 36 weeks: 20 days before delivery: 50 intrapaum: 30 The risk of transmission during breast feeding may be as high as 30-40. Also note that at all stages, risk of HIV transmission is directly related to maternal HIV viral load. Therefore maximum risk , out of given options is peripaum days before delivery intrapaum immediate post paum So to bring this infection rate less than 2 all the HIV positive pregnant woman are staed on anti-retroviral A drugs irrespective of CD 4 count throughout pregnancy. 