Ans. is 'd' i.e., Rubella * Rubella is one of the most teratogenic agents known. Eighty percent of women with rubella infection and a history of rash during the first 12 weeks have a fetus with congenital infection. At 13-14 weeks, the incidence is about 54%, and it is 25% by the end of the second trimester. As the duration of pregnancy increases, fetal infections are less likely to cause congenital malformations.* In order to prevent rubella during pregnancy and congenital rubella syndrome, ACOG recommends that the MMR vaccine should be offered to women of childbearing age who do not have evidence of immunity whenever they make contact with the health-care system. Vaccination of susceptible women should-1) Be part of routine general medical and gynecological care, including college health services.2) Take place in all family planning settings.3) Be provided routinely to unimmunized women immediately after hospitalization, childbirth, or abortion, unless there are specific contraindications.* Vaccination of all susceptible hospital personnel who might be exposed to patients with rubella or who might have contact with pregnant women is recommended. Rubella vaccination should be avoided 1 month before or during pregnancy because the vaccine contains attenuated live virus.* In toxoplasmosis, the incidence and severity of congenital infection depend on the gestational age of the fetus at the time of maternal primary infection. Infection increases with duration of pregnancy, with the risk the fetal infection rising from 6% at 13 weeks to 72% at 36 weeks. Fetal infection is more virulent the earlier the infection is acquired. Treatment of pregnant women is thought to prevent and reduce, but not eliminate, the risk of congenital infection. Spiramycin, used alone, is thought to reduce the risk of congenital infection but not to treat established fetal infection. When fetal infection in diagnosed by prenatal testing, pyrimethamine, sulfonamides and folinic acid are added to spiramycin to eradicate parasites in the placenta and fetus.* Transmission of syphilis from a syphilitic mother to her fetus across the placenta may occur at any stage of pregnancy, but the lesions of congenital syphilis generally develop after the fourth month of gestation, when fetal immunologic competence begins to develop.* Perinatal transmission of hepatitis B occurs primarily in infants born to HbsAg carrier mothers or mothers with acute hepatitis B during the third trimester of pregnancy or during the early postpartum period. Most infections occur approximately at the time of delivery and are not related to breast feeding.