Procedure-related miscarriages and Down syndrome-affected births: Implications for prenatal testing based on women's preferences

Objective: To determine how pregnant women of varying ages, races, ethnicit ies, and socioeconomic backgrounds value procedure-related miscarriage and Down-syndrome-affected birth. Methods: We studied cross-sectionally 534 sociodemographically diverse preg nant women who sought care at obstetric clinics and practices throughout th e San Francisco Bay area. Preferences for procedure-related miscarriage and the birth of an infant affected by Down syndrome were assessed using the t ime trade-off and standard gamble metrics. Because current guidelines assum e that procedure-related miscarriage and Down syndrome-affected birth are v alued equally, we calculated the difference in preference scores for those two outcomes. We also collected detailed information on demographics, attit udes, and beliefs. Results: On average, procedure-related miscarriage was preferable to Down s yndrome-affected birth, as evidenced by positive differences in preference scores for them (time trade-off difference: mean = 0.09, median = 0.06; sta ndard gamble difference: mean = 0.11, median = 0.02; P < .001 for both, one -sample sign test). There was substantial subject-to-subject variation in p references that correlated strongly with attitudes about miscarriage, Down syndrome, and diagnostic testing. Conclusion: Pregnant women tend to find the prospect of a Down syndrome-aff ected birth more burdensome than a procedure-related miscarriage, calling i nto question the equal risk threshold for prenatal diagnosis. Individual pr eferences for those outcomes varied profoundly. Current guidelines do not a ppropriately consider individual preferences in lower-risk women, and the p rocess for developing prenatal testing guidelines should be reconsidered to better reflect individual values. (Obstet Gynecol 2000;96:511-16. (C) 2000 by The American College of Obstetricians and Gynecologists.).