Prenatal anxiety has negative effects on pregnancy and neonate. Both screening tests and invasive diagnostic tests are associated with elevated anxiety level. But a normal fetal karyotype result could improve the anxiety level in high-risk patients. We hypothesized that patients who prefer follow-up without karyotyping may experience increased anxiety and sleep impairment until delivery. Our aim was to determine the effect of invasive diagnostic test decision on anxiety and sleep quality in women with a positive screening result. 132 women were included for the study and three groups were described. The invasive group consisted of women who underwent invasive procedure after a screen-positive test result, the follow-up group consisted of women who preferred non-invasive follow-up after a screen-positive result and the control group consisted of women with screen-negative test results. Participants were evaluated with the State-Trait Anxiety Inventory (STAI) and the Pittsburgh Sleep Quality Index (PSQI) after genetic counseling. They were asked for completing the same questionnaires in the third trimester to establish the course of anxiety and sleep quality throughout pregnancy. STAI scores were significantly higher in both screen-positive groups than in the control group in the first evaluation ( < 0.001). STAI scores decreased in the invasive group and controls while PSQI scores did not significantly change during the course of the pregnancy. However, the anxiety level and sleep quality were worsened over time in the follow-up group. Screen-positive women who preferred to follow up had higher anxiety level and worse sleep quality in the later stages of pregnancy. We concluded that invasive prenatal diagnostic tests could improve anxiety and sleep quality in pregnant women with a screen-positive result for aneuploidy.