All of The following statements about congenital rubella are true except:

Ans. d. Increased risk of congenital malformation if infection occur after 16 weeks Fetal malformations are more common after maternal infection in the first trimester and tend to be more severe and to involve more organ systems. Infection in the second trimester may cause deafness but those infected after 16 weeks suffer no major abnormality.Rubella* Rubella is a teratogenic virus, can be transmitted from fetus to mother.* The fetus is at risk for congenital rubella only during primary infection.* The rate of transmission of rubella varies w ith gestational age. It is highly variable even during the first trimester.Characteristic Features:* Fetal malformations are more common after maternal infection in the first trimester and tend to be more severe and to Involve more organ systems. Infection in the second trimester may cause deafness but those infected after 16 weeks suffer no major abnormality.Risk for congenital defects is related to the gestational age at the time of infectionGestational ageRisk for congenital defectsBefore 11 weeks90%11-12 weeks33%13-14 weeks11%15-16 weeks24%Rubella* Other uncommon abnormalities are: Fetal and neonatal growth retardation, hepatosplenomegaly, thrombocytopenia, meningoencephalitis, radiolucoency of the long bones, myocardial necrosis.* Rare abnormalities: Microcephaly, brain calcifications* Late onset features appearing after 3-12 months include: Interstitial pneumonitis, chronic rubella like rash, recurrent infections, hypogammaglobulinemia, chronic diarrhoea, diabetes mellitus. progressive CNS deteriorationDiagnosis of congenital rubella:* Congenital infection is considered to have occurred if the infant has IgM rubella antibodies shortly after birth or if IgG antibodies persist for >6 months by which time maternally derived antibodies would have disappeared.