[Establishment of medians for maternal serum markers in Down's syndrome screening during the second trimester of pregnancy in north-central region of Jiangxi Province].

OBJECTIVE: To establish the median databases of serum markers for Down's syndrome screening during the second trimester of pregnancy women in the north-central area of Jiangxi Province.
 Methods: Time-resolved fluorometry was used to detect the serum contents of AFP free β-hCG and uE3 in 57 548 pregnant women during 15-20 gestational weeks. Risk evaluation was conducted by LifeCycle 4.0. SAS 9.2 software was used to establish a model of the median fitted equation. The newly constructed median system was used to reassess the risk of Down's syndrome development in pregnant women.
 Results: The medianand built in medianof north-central region in Jiangxi Province are significantly different (Z=2.201, P=0.028). The relationship between the median of the triple index and the gestational age was analyzed by the weight regression model. The relationship between the MoM value and the weight was used to calculate the reciprocal model. The median of the new system was more efficiency than the built in median. In the median of the new system than the reference, the detection rate improved from 62.75% to 72.55%, false positive rate reduced by 5.84% to 4.94%.
 Conclusion: The newly constructed median system is suitable for Down's syndrome screening in the north-central region of Jiangxi Province.