True regarding rubella infection in pregnancy is: March 2010
Ans. C: IgM antibodies in fetus reflects immunity Fetal rubella syndrome is a congenital disorder resulting from primary maternal infection with the rubella virus. It is characterized mainly by deafness, mental retardation, congenital cataract, hea defects, and other structural anomalies that may be found with variable severity and frequency. During acute rubella in pregnancy, the rate of congenital infection is over 90% in the 12 first weeks of pregnancy, approximately 60% in weeks 13 to 17, 25% in weeks 18 to 24 and then increases again during the last month of pregnancy. Etiology: It is caused by a RNA togavirus, which is the only member of the genus Rubivirus. The fetus is infected by transplacental transmission. Administration of rubella vaccine has significantly reduced the incidence of maternal infection, although reinfection after vaccination is possible. The development of fetal infection reaches 50% among those exposed during the first trimester and 20% during the second trimester. Diagnosis: The most frequent sonographic findings are cardiac malformations (in paicular, septal defects), eye defects (cataracts, microphthalmia, and retinopathy), microcephaly, hepatomegaly, splenomegaly and growth restriction. Deafness and mental retardation are expected after bih. Test for rubella specific antibody (IgM) should be done within 10 days of the exposure to know whether patient is immune or not. Associated anomalies: Occasionally the following anomalies can be associated with the classic findings of fetal rubella syndrome: renal disorders, hypospadias, cryptorchidism, meningocele, glaucoma, patent ductus aeriosus, and peripheral pulmonary stenosis. Differential diagnosis: All the conditions that can be associated with congenital hepatomegaly and/or cataract should be excluded. It includes congenital infections (TORCHS), fetal anemia, fetal liver tumor, chondrodysplasia punctata, NeuLaxova syndrome, Smith-Lemli-Opitz syndrome, and Walker-Warburg syndrome. Prognosis: Intrauterine death may occur. Postnatal impact of the intrauterine infection varies from absence of any defect to all the anomalies mentioned above with variable severity. The agent may remain for years in the tissues, causing chronic infection and its complications (such as diabetes mellitus due to chronic viropathy of the pancreas). Management: Termination of pregnancy should be considered every time fetal infection is detected during the first trimester, due to the severity of the condition in this group. After bility, monthly sonographic monitoring for growth and follow-up of the anomalies is recommended. Prevention: Women found to be susceptible during pregnancy should be offered vaccination postpaum and before discharge from the hospital (vaccine is not recommended in pregnancy). Breastfeeding is not a contraindication to receiving the rubella vaccine.
Risk of congenital infection is more in last trimester
Vaccination is indicated in pregnancy for protection
IgM antibodies in fetus reflects immunity
It is caused by DNA virus