Descriptive Study of Rubella Titer Status in Infertility Patients

There is a 6.4 percent incidence of rubella exposure during pregnancy in the U.S. Given the severe effects rubella can have on a developing fetus, vaccination of women prior to pregnancy is important. Women seeking fertility treatment therefore present a population of patients primed for the vaccination. This study collected and analyzed rubella-specific immunoglobulin G (RV-IgG) titer statuses and corresponding demographics of infertility patients to identify patients at risk of rubella nonimmunity.

The study consisted of a retrospective review of electronic medial records (EMR) of female patients, ages 18 to 50, who were new patients receiving an infertility workup at a Midwestern reproductive endocrinology clinic from Jan. 1, 2010 through Dec. 31, 2014. Of those patients who had RV-IgG titers noted in their EMR, the following demographics were collected: age, race, gravidity and parity, state of residence, and community size.

There were 750 patients included in the study. Rubella titers were drawn on 72.7 percent of the patients. Of those drawn, 90.8 percent had a positive rubella titer. Most of the participants (92.3 percent) were identified as Caucasian/White. Caucasians/Whites, Asians, and African Americans/Blacks had the highest rates of rubella immunity, while American Indians/Alaskan Natives had the lowest rates of immunity (p=0.0006). Nulligravida participants had a positive rubella titer rate of 94.1 percent, while primigravida participants had a rate of 89.8 percent (p=0.04). Participants living in the largest sampled communities had the lowest rates of positive rubella titers, while those living in the smallest communities had the highest rates of positive rubella titers, although these findings were not statistically significant.

Of the infertility patients, 27.3 percent did not have an RV-IgG titer drawn as part of their fertility workup. Of the 72.7 percent of patients for whom titers were checked, nearly 10 percent were not immune to rubella. While there are a couple reasons why a patient may not have a positive titer, lack of immunization is the most common reason. Data analysis identified significance in the difference in titer status only with respect to race and gravidity, and those findings, particularly race, must be viewed critically in light of the study population. While the statistical significance of the study may be limited, there is clinical significance in identifying infertility patients at highest risk of rubella nonimmunity so vaccination education and efforts can be focused accordingly.