| Down' s syndrome is entitled trisomy 21 syndrome. It is the most common chromosomal disease in live birth newborns. Down' s syndrome is one of the most common causes which leads to the still-birth the abortion and the fetus birth defect. Along with social improvement and civilized development, people make further acquaintanceship with aristogenesis, so the serum prenatal screeing of Down' s syndrome has become widespread.Massive research has showed that we could detect the trisomy 21 syndrome effectively if we has carried out the prenatal screening with AFP and free β -hCG. If we could establish the different gestational weeks-median of AFP and β -hCG of the normal pregnant women in our country, we could increase the detection rate of trisomy 21 syndrome efficiencily. The median of the software applied has been different from the exact median of the countrymen because of the race, so it is necessary to establish the median of the pregnant women in our district.Objective1. To investigate the relationship between the pregnant women' s age, gestational week body weight gravidity .. parity and the maternal serum markers in the second trimester.2. To establish the different gestational weeks-median of serum AFP and freeβ-hCG in the district by serum screening of large samples and compare the high risk-proportion of different age groups to discuss the range of high risk-people.3. To investigate the relationship of maternal serum high level AFP or free β -hCG and the obstetric complications or pathological gestation for the early detection and diagnosis.Methods1. Material and Screening Index: In the course of 15-20 gestational weeks of pregnancy duration, the pregnant women accepted hemospasia in the local hospital and then the blood-serum were segregated. The samples were conserved in the condition of -20℃ by the refrigerator and delivered to the antenatal diagnosis center of the women' s hospital school of Medicine Zhejiang University to test the maternal serum markers in the second trimster including AFP and free β-hCG.2. Reagent and Apparatus: We used time-resolved fluorescence immunoassay (DELFIA ,Wallac).The double labeling kit (AFP/free-β hCG) was purchased from American Perkin Elmer Company. The checking instrument adopted Wallac fully automated immunoassay. We underwent the operation according to reagent specification critically. The risk ratios were caculated by prenatal screening risk-caculated software of trisomy 21 syndrome which was supplied was supplied by the Wallac Company.3. Statistical Methods: We utilized the SPSS 11.0 software to analyze. The statistical methods include t-test correlation analysis and the test of normality.RusultsPart I the Establishment of the Median of Maternal Serum Markers Including AFP and Free β -hCG and the Research of its Influencing Factors1. The measured value and adjusted value of serum AFP in second trimester arepositively related to gestational weeks. The correlation coefficients are 0. 281 and 0. 048, and the P values are both less than 0. 001. But the measured value and adjusted value of serum free β -hCG in second trimester are negatively related to gestational weeks. The correlation coefficients are -0.231 and -0. 037, and the P values are both less than 0.001.2. The measured values of serum AFP and the serum free β -hCG in the secondtrimester are negatively related to pregnant woman' s weight. The correlation coefficients are respectively -0.160 and -0. 130, and the P values are both less than 0.001.3. The measured and adjusted value of the serum AFP and the serum free β -hCG are not related to the age of pregnant women, and the P values are all more than 0. 05.4. The serum AFP MoM in the second trimester is positively related to gravidity. The correlation coefficient is 0. 062, and the P value is less than 0. 001. The serum β-hCG MoM in the second trimester is negatively related to gravidity. The correlation coefficient is -0. 028, and the P value is 0.02.5. The serum AFP MoM and free β -hCG MoM in second trimester are not related to parity, and the P values are both more than 0.05.6. We compare the median of the serum AFP value and free β -hCG value in different gestation weeks in the research with the median of both in the statistical software.(1) The measured value of AFP median in this research is higher than the intrinsic value in the software. And both comparison is not significantly different. The t value is 0. 889, and the P value is 0.395.(2) The measured value of free β -hCG median is higher than the intrinsic valuein the software. And both comparison is not significantly different. The t value is 1. 234, and the P value is 0.245.7. The detection rate of high risk in Down' s syndrome is gradually raised along with the increased age. And the detection rate of high risk in DS isobviously related to the pregnant women age. The correlation coefficient is 0.918, and the P value is less than 0.001.Part II the Relationgship of High Level Serum Markers in the Second Trimester and Pregnancy Complications or Pathological Gestation 1 When free β-hCG MoM value is not less than 2.0(1) When the first gestation, the MoM value of high level AFP in the second trimester is related to premature birth and infant of low-birth weight of premature birth. The P values are 0.017 and 0.001 separately. The RR values are 7. 059 and 33.545 separately.(2) When the second gestation, the MoM value of high level AFP in the second trimester is related to premature birth and mature infant of low-birth weight. The P values are 0. 021 and 0. 010 separately. The RR values are 6. 696 and 25. 667 separately.(3) When the third gestation and more, the MoM value of high level AFP in the second trimester is related to pregnancy with severe anemia. The P value is 0. 039.(4) Regardless of gravidity, the MoM value of high level AFP in the second trimester is related to complete placenta praevia and mild apnea of infant. The P values are 0. 001 and 0. 002 separately. The RR values are 21. 525 and 17.631 separately.2 When free AFP MoM value is between 0.5 and 2.0:(1) When the first gestation, the MoM value of high level free β-hCG in thesecond trimester is related to oligoamnios. The P value is 0. 009. The RR value is 5. 588.(2) When the third gestation and more, the MoM value of high level free β -hCG in the second trimester is related to prolonged pregnancy III~° nephelium of amniotic fluid and fetal distress in uterus. The P values are separately 0. 004 0. 004 and less than 0. 001, and the RR values are 4. 297 2. 088 and 2. 427 separately;(3) The MoM value of high level free β -hCG in the second trimester is related to the placenta implantation regardless of gravidity. The P value is 0.04, and the RR value is 5.581;3, When free β-hCG MoM value is between 0.5-2.0(1) When the first gestation , the MoM value of high level AFP in the second trimester is related to premature rupture of fetal membranes. The P value is 0.046. The RR value is 2.483.(2) When the second gestation , the MoM value of high level AFP in the second trimester is related to severe preeclampsia. The P value is 0. 005. The RR value is 10.904.(3) When the third gestation and more, the MoM value of high level AFP in the second trimester is related to severe preeclampsia and the P value is 0. 035. The RR value is 8.103.(4) Regardless of gravidity, the MoM value of the high second-trimester maternal serum AFP is related to complete placenta praevia. And the P value is 0. 001. The RR value is 25. 3.Conclusions1 The influencing factors of the measured values of serum AFP and free β -hCG in the second trimester are: gestational week, the pregnant women' s weight and gravidity. We should ajust the median with these influencing factors in order to establish the right median of the serum markers in the second trimester of the district.2, The measured values of the AFP MoM and free β -hCG MoM are higher than the intrinic median in the analyzed software.3 When the pregnant women' s age is younger than 35, the detection rate of the high risk of Down' s syndrome is related to the age obviously.4 The high level serum markers in the second trimester are related to some obstetric complications or pathological pregnancies including prematurelabor, infant of low-birth weight when premature labor, complete placenta praevia, infant with mild apnea oligoamnios successful tocolysis of threatened premature labor prolonged pregnancy III° nephelium of amniotic fluid, placenta implantation, fetal distress in uterus, premature rupture of fetal membranes, severe preeclampsia and FGR. |
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