Rubella in pregnancy: intrauterine transmission and perinatal outcome during a Brazilian epidemic

Abstract

Sixty pregnant women with clinical signs of rubella and specific rubella antibodies were studied between January 1999 and December 2002 in order to determine the intrauterine rubella transmission rate and the presence of the virus in amniotic fluid and fetal tissues by nested PCR. Thirty-three patients presented rubella before 12 weeks of gestation and 27 after 12 weeks. Gestational age at the time of acute rubella was determined on the basis of the date of last menstruation and the first trimester ultrasound scan. Thirteen patients with clinical features of rubella before 12 weeks of gestation were submitted to amniocentesis. Three products of conception were analyzed. The presence of the rubella virus was determined by nested PCR. IgM and IgG antibodies were analyzed in neonatal samples at birth and at 3 months of age using a capture immunoassay. Newborn follow-up was based on the presence of congenital rubella syndrome-compatible defects, anti-rubella antibodies, echocardiographic alterations, brainstem evoked response audiometry, and ophthalmological pathology. Five miscarriages and four fetal deaths were observed in the group of patients presenting clinical features before 12 weeks of gestation. IgM antibodies were detected in seven neonates at birth and at 3 months of age. Deafness was observed in three cases and pigmentary retinopathy in one case. Fourteen of the 16 samples (13 amniotic fluid and 3 fetal tissue samples) submitted to virological analysis tested positive. Four fetal deaths, five miscarriages (one with negative virology) and seven newborns with anti-rubella IgM at birth and/or at 3 months age were observed in the group with rubella before 12 weeks of gestation. There were three cases in which virological analysis of the amniotic fluid samples was positive (infected) while the newborn showed no signs of congenital rubella syndrome and anti-rubella IgM were absent. When maternal rubella occurred after 12 weeks of gestation, no fetal or neonatal rubella signs were observed. Eradication of congenital rubella syndrome is possible since vaccination campaigns continue and all services related to the health care of children, adolescents and women have become aware of the significance of the problem and are collaborating. All pregnant women in Brazil should be screened for the rubella antibody and the susceptible group should be vaccinated after giving birth.