Preferences of pregnant women for amniocentesis or chorionic villus sampling for prenatal testing: comparison of patients' choices and those of a decision-analytic model.

Decision analytic models have suggested that the choice of amniocentesis or chorionic villus sampling for prenatal genetic testing is a utility-driven decision. We compared preferences for prenatal testing among 156 pregnant women who had chosen either amniocentesis (n = 82) or chorionic villus sampling (n = 74) for the indication of maternal age. We also compared their choices with those of a decision-analytic model based on their preferences, and age-specific rates of spontaneous abortion and chromosomal abnormalities. Preferences were assessed using written scenarios describing potential outcomes of prenatal testing, and were recorded on linear rating scales. The differences in preference ratings for first- vs second-trimester prenatal diagnosis of a normal child (4.2 vs -1.6, p = 0.0004), and for first- vs second-trimester abortion of an abnormal fetus (4.4 vs -1.6, p = 0.01), were significantly greater among women choosing chorionic villus sampling than among women choosing amniocentesis. There were no significant differences between chorionic villus sampling and amniocentesis patients in their preference ratings for test-related miscarriage, disconfirmed results at pregnancy termination, or maternal morbidity from therapeutic abortion. After adjusting for demographic and obstetric factors, the difference in preferences for early vs late prenatal diagnosis was an independent predictor of the choice of chorionic villus sampling in a multivariate model. Among women whose decision analyses selected amniocentesis, 56.8% had chosen amniocentesis, and among women whose analyses selected chorionic villus sampling, 63.2% had chosen chorionic villus sampling (p = 0.05). We conclude that the preferences of pregnant women for the outcomes of prenatal testing were associated with their choice of amniocentesis or chorionic villus sampling. In addition, the choice of prenatal test made by the majority of women was concordant with that of a decision-analytic model that incorporated their preferences. Nevertheless, because many women made choices that were discordant with their decision-analytic results, further research into the bases for their choices is warranted.