Pregnancy Outcome Following Inadvertent Rubella Vaccination in 1-4 Weeks Periconceptional Period in 60 Pregnant Women

Rubella virus is a potent teratogen. Risk of rubella virus induced multisystem fetal malformation is highly dependent on the gestational age at the time of infection. Because the rubella vaccine is an attenuated live virus, its use is contraindicated during pregnancy. Our objective was to examine whether exposure to rubella vaccine during 1-4 weeks periconceptional period can cause any adverse pregnancy outcome or Congenital Rubella Syndrome (CRS).

This prospective study was performed in 60 pregnant women who received rubella vaccine inadvertently 1-4 wks pre or post conception. Time of conception was determined by last menstrual period (LMP) and first trimester sonography. In addition to gathering mother's obstetric and demographic information, all neonates were evaluated for CRS signs by systemic physical examination and anti rubella IgG and IgM antibody levels in cord blood samples.

Mean maternal age was 21.8±2.9 years and 58.3% of pregnancies were unintended. In 90% of mothers there were no post vaccination side effects. None of the mothers had a history of drug abuse, smoking or teratogenic exposures. Mean neonatal weight was 3108±581 gr and 6.7% of them were premature. There was no increase in the rate of adverse pregnancy outcome, (abortion, preterm labour, post term pregnancy, fetal demise, obstetric hemorrhage, pregnancy related major malformation). No signs of CRS were found in the neonates based on systemic physical exam. Mean value of cord blood anti-rubella IgG level was 143.9±69.5 IU/mL. Cord blood anti-rubella IgM was negative in all of the neonates.

It seems that inadvertent rubella vaccination 1-4 weeks before and after conception does not cause CRS in neonate and therapeutic abortion is not indicated however since in rare instances clinical manifestations of rubella have appeared years after the congenital infection, women planning to get pregnant should not be vaccinated against rubella one month before and throughout pregnancy.