SAN ANTONIO – Implementing universal paternal Rh screening would be a cost-effective safety strategy among patients receiving in vitro fertilization, according to a model that used up-to-date data and accounted for ethnic variations in the prevalence of the Rh (D) antibody.
Using a universal Rh screening strategy for semen donors to Rh (D) negative women undergoing in vitro fertilization would result in a cost savings of $11.01 per patient, or $1,120,000 per 100,000 Rh negative IVF pregnancies, according to Pietro Bortoletto, MD, and his coauthors. Their findings were presented during a poster session at the annual meeting of the American Society for Reproductive Medicine.
If paternal Rh factor status is unknown, vaginal bleeding during pregnancy prompts maternal administration of anti-D immune globulin if the mother is Rh (D) negative to prevent hemolytic disease of the fetus and newborn. However, wrote Dr. Bortoletto and his colleagues, “in the IVF population, where paternity status is presumed to be certain, the Rh (D) status of the male partner can be used to triage Rh (D) negative women to more appropriate administration of anti-D globulin.”
To see whether a universal paternal Rh screening strategy would be cost effective, Dr. Bortoletto, a resident physician in obstetrics and gynecology at Harvard Medical School and Brigham and Women’s Hospital, both in Boston, and his collaborators constructed a decision tree to estimate cost savings. The model compared a universal paternal-screening strategy for Rh (D) negative women undergoing IVF with the current standard of practice, which does not involve routine Rh (D) screening for the sperm donor.
In constructing the model, the investigators drew on published data showing that first trimester bleeding is more common in women who undergo IVF: It occurs in one-third of these women, compared with about 20% of the general pregnant population.
They also established probability estimates of pregnancy loss before 20 weeks, with and without first trimester bleeding (0.34 and 0.18, respectively); third trimester bleeding, with and without first trimester bleeding (0.05 and 0.02); and trauma in pregnancy (0.08). They estimated the overall probability of the pregnancy producing an Rh positive neonate at 0.62.
An additional factor that Dr. Bortoletto and his collaborators took into account was the variable prevalence of Rh factor by ethnicity; in the United States, it’s most common in white men and least common in Asian men, with intermediate prevalence in African American and Hispanic men.
When paternal ethnicity was included in the analysis, savings were greatest with white sperm donors, at $1,889,000 per 100,000 Rh negative IVF pregnancies. The lower prevalence of Rh factor in Asian men meant that the strategy was not cost effective in this population since it would cost a net $2,323,000 per 100,000 Rh negative IVF pregnancies.
“A targeted screening approach, by paternal ethnicity, may be a targeted strategy for cost reduction,” wrote Dr. Bortoletto and his colleagues.
Figures for cost estimates were drawn from data from the Centers for Medicare & Medicaid (CMS) using 2017 dollars. The cost for tests to determine blood type and Rh status ranged from $6 to $11, so the investigators set the cost estimate of $8.20. The cost for an antibody screen was estimated at $5.25 (range, $4-$7).
The cost for a 300 mcg dose of anti-D immune globulin was estimated at $93.93 (range, $79-$109), and administration costs were $27.04 (range, $25-$28). Kleihauer-Betke testing to determine the amount of fetal blood in maternal circulation was pinned at $10.61 (range, $8-$14).
Even when the lowest end of the cost range of anti-D immune globulin was used, a universal screening model would still realize a cost savings of $820,000 per 100,000 Rh negative IVF pregnancies. When Rh screening cost was set at $11 – at the high end of the range – “the strategy still remained favorable at $981,000,” wrote Dr. Bortoletto and his colleagues.
“Universal paternal Rh screening provides a cost saving intervention by preventing nonindicated and costly administration of anti-D immune globulin in the IVF population presenting with bleeding or trauma in pregnancy,” they wrote.
Dr. Bortoletto reported no outside sources of funding and no conflicts of interest.
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