Objective: To identify predictors of prenatal genetic testing decisions and explore whether racial or ethnic and socioeconomic differences are explained by knowledge, attitudes, and preferences.
Methods: This was a prospective cohort study of 827 English-, Spanish-, or Chinese-speaking pregnant women presenting for care by 20 weeks of gestation at 1 of 23 San Francisco Bay-area obstetrics clinics and practices. Our primary outcome measure for women aged less than 35 years was any prenatal genetic testing use compared with none, and for women aged 35 years or older, prenatal testing strategy (no testing, screening test first, straight to invasive diagnostic testing). Baseline questionnaires were completed before any prenatal test use; test use was assessed after 30 gestational weeks.
Results: Among women aged less than 35 years, no racial or ethnic differences in test use emerged. Multivariable analyses yielded three testing predictors: prenatal care site (P = .024), inclination to terminate pregnancy of a Down-syndrome-affected fetus (odds ratio 2.94, P = .002) and belief that modern medicine interferes too much in pregnancy (odds ratio .85, P = .036). Among women aged 35 years or older, observed racial or ethnic and socioeconomic differences in testing strategy were mediated by faith and fatalism, value of testing information, and perceived miscarriage risk. Multivariable predictors of testing strategy included these 3 mediators (P = .035, P < .001, P = .037, respectively) and health care system distrust (P = .045). A total of 29.5% of screen-positive women declined amniocentesis; 6.6% of women screening negative underwent amniocentesis.
Conclusion: Racial or ethnic and socioeconomic differences in prenatal testing strategy are mediated by risk perception and attitudes. Screening is not the best choice for many women. Optimal prenatal testing counseling requires clarification of risks and consideration of key attitudes and preferences regarding the possible sequence of events after testing decisions.