Objectives To explore women's decisional conflict in the pathway of prenatal screening and testing (PreST) in Finland and to evaluate a counseling service. Methods Self-completion surveys were conducted at two medical settings (screening and further testing) of PreST. Decisional Conflict Scale (DCS) was the main measure. Different types of statistical tests were used to compare women's decisional conflict at different medical settings of PreST, and before-after pre-test counseling. Multivariable linear regressions analyzed the influences of the medical settings and other factors on women's decisional conflict. Results Compared to women in population-based screening, women in further testing (before pre-test counseling) were more likely to feel well informed (P < 0.001), had increased values clarity (P < 0.001), but more likely experienced uncertainty (P = 0.040). Besides medical settings, maternal age, gravidity and previous experience of fetal aneuploidy significantly influenced decisional conflict. After counseling, screen-positive women felt better informed (P < 0.001), had increased values clarity (P < 0.001), perceived more support (P < 0.001), and had better decision certainty (P < 0.001) than before counseling. Conclusions Medical settings influence women's decisional conflict during PreST. Individual counseling is effective in improving screen-positive women's decisional conflict. This research adds knowledge and experience on developing decision-making supports across the pathway of PreST.