Ans. d (Vaginal Delivery) (Ref. Harrison 18th/ p 38, 1082)HUMAN IMMUNODEFICIENCY VIRUS (HIV)# Exposures, which increase the risk of mother-to-child transmission, include -- Vaginal delivery, Preterm delivery; Maternal bleeding, and Trauma to the fetal skin,# Additional factors that may increase the risk of transmission include:- Recent infection with high maternal viral load,- Low maternal CD4 T cell count, prolonged labor,- Prolonged length of membrane rupture, and- The presence of other genital tract infections, such as syphilis or herpes.# Maternal transmission to the fetus occurs most commonly in the perinatal period.# 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 infant/fetus ranges from 15 to 25% in industrialized countries and from 25 to 35% in developing countries.# HIV transmission from mother to the baby can be minimized by:A. Antepartum Zidovudine therapy to mother and to the neonate after birthB. Maternal Vitamin A therapyD. Avoidance of breast feeding# The rate of MOTHER-TO-CHILD TRANSMISSION IS APPROACHING 1 % OR LESS IN PREGNANT women who are receiving combination antiretroviral therapy for their HIV infection.WHO guidelines for PMTCT drug regimens in resource-limited settings:PREGNANCYLABOURAFTER BIRTH: MOTHERAFTER BIRTH: INFANT RecommendedAZT after 28 wkssingle dose nevirapine; AZT + 3TCAZT+3TC for seven daysSingle dose nevirapine; AZT for seven daysAlternative (higher risk of drug resistance)AZT after 28 wksSingle dose nevirapine-Single dose nevirapine; AZT for seven daysMinimum (less effective)-Single dose nevirapine; AZT + 3TCAZT+3TC for seven daysSingle dose nevirapineMinimum (less effective; higher risk of drug resistance)-Single dose nevirapine-Single dose nevirapineTreatment# The majority of cases of mother-to-child (vertical) transmission of HIV-1 occur during the intrapartum period.# Mechanisms of vertical transmission include infection after rupture of the membranes and direct contact of the fetus with infected secretions or blood from the maternal genital tract.# In women with HIV infection who are not receiving antiretroviral therapy, the rate of vertical transmission is approximately 25%.# Cesarean section and treatment with zidovudine, administered both before and during delivery, decrease the rate of vertical transmission.# In a meta-analysis, zidovudine treatment of both the mother during the prenatal and intrapartum periods and the neonate at birth reduced the risk of vertical transmission to 7.3%.# The combination of elective cesarean section plus zidovudine treatment reduced the risk of vertical transmission to 2%.CYTOMEGALOVIRUS INFECTION# The most common cause of congenital viral infection in the United States is cytomegalovirus (CMV).# Severe CMV disease in the newborn is characterized most often by petechiae, hepatosplenomegaly, and jaundice.# Chorioretinitis ("tomato sause & cheese" appearance), microcephaly, intracranial calcifications, hepatitis, hemolytic anemia, and purpura may also develop.# Central nervous system involvement, resulting in the development of psychomotor, ocular, auditory, and dental abnormalities over time, has been described.RUBELLA# First trimester rubella carries a high risk of fetal anomalies, though the risk decreases significantly later.# Congenital rubella may be diagnosed by PUBS with the detection of IgM antibodies in fetal blood.HERPESVIRUS# The acquisition of genital herpes during pregnancy is associated with spontaneous abortion, prematurity, and congenital and neonatal herpes.# Infection occurs equally in all three trimesters.# In women who acquired genital herpes shortly before delivery, the risk of transmission is high.# The risk of active genital herpes lesions at term can be reduced by prescribing acyclovir for the last 4 weeks of pregnancy to women who have had their first episode of genital herpes during the pregnancy.# It is recommended that pregnant women with active genital herpes lesions at the time of presentation in labor be delivered by cesarean section.PARVOVIRUS (human parvovirus B19)# It rarely causes sequelae.# But susceptible women infected during pregnancy may be at risk for fetal hydrops secondary to erythroid aplasia and profound anemia.TOXOPLASMOSIS# The diagnosis of congenital toxoplasmosis is possible through sampling of fetal umbilical blood.# If there is no evidence of placental/fetal infection, single-drug treatment with spiramycin is recommended.# Triple-drug therapy with spiramycin, pyrimethamine, and sulfa is recommended if there is evidence of fetal infection and the woman does not wish to terminate the pregnancy or cannot terminate it because of advanced gestational age.