PURPOSE Rational decision theory implies that explicitly trading off the pros and cons of alternatives (i.e. deliberation) leads to better decisions. Some studies, however, claim that deliberation can decrease decision quality. We studied whether deliberation is associated with better decision quality and making an informed choice about prenatal screening. METHODS In a sample of 1100 pregnant women making a decision about prenatal screening for Down syndrome we measured deliberation (on a 6-item scale, á = .81), informed choice (using the MMIC, Marteau et al., 2001), decision quality (using the Decisional Conflict Scale, O'Conner, 1995), and decision satisfaction (on a 4-item scale, á = .84). Informed choice was defined as a value-consistent choice based on sufficient knowledge. Value consistency is defined as choosing for the test when having a positive attitude towards testing or choosing to decline the test when being negative. RESULTS There was a modest positive correlation between deliberation and decision quality (r = .19, p < .001), but a low correlation with decision satisfaction (r=.09, p < .01). There was no clear cut association between deliberation and whether or not choices were informed. Those making an informed choice to accept screening reported less deliberation compared with those making an informed choice to accept screening and those making informed or uninformed choices to decline screening (F(3,773)= 18.2 (p < .001). Women who were categorized as having insufficient knowledge deliberated less than women who had sufficient knowledge (t(769) = 3.0, p <.001), and reported feeling less informed (t(777)= 4.7, p<.001). Although women who made value-consistent decisions reported a better decision quality than women who made value-inconsistent decisions (t(754) = 3.4, p <.001), there was no difference regarding deliberation. CONCLUSIONS While deliberation about a decision to undergo prenatal testing is associated with better self-reported decision quality it is not clearly related to whether the choice is classified as value consistent and informed. Experimental studies are needed to ascertain whether explicit deliberation as predicted by Rational decision theory optimises decision quality.