From the Guidelines
A reactive rubella IgG test during pregnancy is a good thing, as it indicates the pregnant woman has immunity against rubella, protecting her and the fetus from the risks associated with rubella infection. This immunity is crucial because rubella infection during pregnancy, especially in the first trimester, can cause congenital rubella syndrome in the developing fetus, which may lead to serious birth defects including heart problems, hearing impairment, eye defects, and developmental delays 1. The presence of serum rubella IgG antibody is the only reliable evidence of previous rubella infection, and clinical diagnosis of rubella is unreliable and should not be considered in assessing immune status 1.
Pregnant women are routinely screened for rubella immunity early in pregnancy, and if a woman is found to be non-immune (negative rubella IgG), she should be vaccinated after delivery to protect future pregnancies, as the rubella vaccine (MMR) is contraindicated during pregnancy because it contains live attenuated virus 1. No specific action is needed for women with positive rubella IgG results as they already have the necessary protection. The Centers for Disease Control and Prevention (CDC) recommends that women of childbearing age who do not have documentation of rubella vaccination or serologic evidence of rubella immunity should be vaccinated with MMR, if they have no contraindications to the vaccine 1.
Some key points to consider include:
- The importance of protecting women of childbearing age against rubella, as highlighted by the potential risks of congenital rubella syndrome 1
- The need for routine serologic testing for rubella antibody during clinic visits for routine health care, premarital evaluation, family planning, or diagnosis and treatment of sexually transmitted diseases to identify women who are not immune to rubella before they become pregnant 1
- The recommendation that postpartum rubella vaccination of all women not known to be immune could prevent up to half of CRS cases 1
- The fact that MMR vaccine coverage in the United States is high, with an estimated 91.5% of children aged 19–35 months having received 1 dose of MMR vaccine in 2010 1.
Overall, a reactive rubella IgG test during pregnancy is a desirable outcome, as it indicates the woman has immunity against rubella and is protected from the risks associated with rubella infection during pregnancy.
From the Research
Rubella Infection in Pregnancy
- Rubella infection during pregnancy can cause miscarriages, congenital defects, and Congenital Rubella Syndrome (CRS) 2, 3, 4.
- A reactive rubella IgG indicates immunity to rubella, which is generally a good thing in pregnancy as it suggests the woman is not susceptible to rubella infection 2, 5.
Immunity to Rubella
- A study found that 93.7% of pregnant women were immune to rubella, with an IgG antibody concentration ≥10 IU/ml 2.
- Another study found that individuals can have evidence of protective immunity against rubella despite negative RV-IgG, as measured by cell-mediated immunity and anti-E1 RV-IgG 5.
Congenital Rubella Syndrome (CRS)
- CRS can cause a range of abnormalities, including cardiac septal defects, pulmonary artery stenosis, microcephaly, cataract, microphtalmia, and hepatosplenomegaly 3.
- A study found that the risk of fetal damage from rubella infection is lower in the second trimester, and prenatal diagnosis can identify the rubella-infected fetus, allowing parents to make informed decisions 6.
Screening and Vaccination
- Pregnant women should be screened for rubella antibody, and susceptible women should be vaccinated after giving birth to prevent congenital rubella syndrome 4.
- A study found that vaccination campaigns can help eradicate congenital rubella syndrome, and all services related to healthcare should be aware of the significance of the problem and collaborate to prevent it 4.