All women should be offered additional carrier screening prior to pregnancy, regardless of their ethnic background, according to a new opinion issued by the American College of Obstetricians and Gynecologists’ (ACOG) Committee on Genetics (Obstet Gynecol 2017;129:e35–40). The opinion also suggests that if a woman requests a test or type of screening not offered by her physician, the test should be made available to her after she receives counseling on its limitations, benefits, and alternatives.
In the past ACOG recommended ethnic-based screening targeted toward specific populations known to have a higher risk for certain disorders, like women of Ashkenazi Jewish descent at increased risk for Tay-Sachs disease. However, in today’s multiracial society an individual’s ancestry may not be so clear-cut, and “the pretest probability of being a carrier for a specific disorder may not be consistent with previous assumptions about the prevalence of that disorder in the various ethnic and racial groups with which a patient identifies,” according to the opinion.
Given this reality, the opinion suggests that ethnic-specific, panethnic, and expanded carrier screening all are acceptable strategies for prepregnancy and prenatal carrier screening. Physicians should adopt a standard approach and offer it to each patient, preferably before pregnancy. Once counseled, patients have the right to decline any or all carrier screening.
Expanded carrier screening does not replace any prior risk-based screening recommendations, and all patients who already are pregnant or are considering pregnancy should be offered carrier screening for cystic fibrosis, spinal muscular atrophy, thalassemias, and hemoglobinopathies, according to the opinion.
The authors emphasized that women should undergo carrier screening for any particular condition just once in their lifetimes, in order to avoid repeat screens and unnecessary costs.