Pregnancy outcomes of women with failure to retain rubella immunity

We sought to explore the clinical variables associated with the loss of rubella immunity during pregnancy and to determine if these changes are linked to obstetrical complications.

This is a case-control study in which women were identified whose rubella antibody titers were equivocal or non-immune and compared to those who had retained immunity. Two hundred and eighty-five cases were identified and compared to the same number of controls using Student's t test, Mann-Whitney U-test or Fisher's exact test. Univariate and multivariate logistic regressions were employed.

Subjects with diminished immunity were more likely to have public insurance and higher gravidity with a trend toward increased tobacco use. Diminished rubella immunity was not associated with adverse obstetrical outcomes, including preterm birth and pre-eclampsia and is likely not a risk factor for these pregnancy outcomes.

While no adverse pregnancy outcomes were associated with a loss of rubella immunity, women with greater number of pregnancies appear to lose their immunity to rubella. This relationship needs to be explored further and if proven, revaccination prior to pregnancy may need to be addressed.