Aim: To determine the current median values for hormone parameters used in first trimester screening test for Kayseri province and to compare the median values with those in the software used for reporting of screening test and those detected for other regions found with similar studies.

Material and Methods: The data from first trimester screening tests of 1108 pregnant women admitted in 2018 were used in the study. Free β-hCG (free, beta human chorionic gonadotropin) and PAPP-A (Pregnancy-associated plasma protein A) levels were recorded together with demographic characteristics for pregnant women. We compared MoM values calculated based on weekly median values in the software and newly calculated MoM values.

Results: Median values for ß-hCG on week 12 and for PAPP-A on week 11 or 12 in the screening tests were significantly lower than current median values (p<0.001 and p<0.001, respectively). MoM values calculated according current median values were significantly higher in both parameters at all time points (p<0.001). The number of pregnant women reported to be at risk was 5 previously while of the pregnant women who were reported to have no risk, additional 8 pregnant women were considered as at risk for Down syndrome according to new median values for free ß-hCG including 2 pregnant women from week 11, 5 pregnant from week 12 and 1 pregnant women from week 13. The number of pregnant women reported to have PAPP-A value <0.5 MoM was 159 according to median values used in the software but it was decreased to 128 according to current median values. Elazığ province did not differ from Kayseri province regarding median values at all values while highest percent bias were found in Mersin regarding PAPP-A. For free ß-hCG, median values for Kayseri were found to be significantly lower from Van, Eskişehir, Mersin and İstanbul provinces at all weeks (p<0.001).

Conclusion: The use of current median values will improve performance of prenatal screening tests.