Krantz David A, Hallahan Terrence W, Macri V James, Macri James N
Research Division, NTD Laboratories, Huntington Station, New York 11746, USA.
Prenat Diagn. 2005 Aug;25(8):635-40. doi: 10.1002/pd.1188.
OBJECTIVE(S): To estimate weight and ethnic group correction factors for first-trimester screening markers.
Ethnic-specific median MoM free beta hCG and pregnancy associated plasma protein A (PAPP-A) and delta nuchal translucency values were calculated for cohorts of maternal weight (20 lb each) using data from 51,206 patients undergoing first-trimester screening. False-positive rates for Down syndrome and trisomy 18 were evaluated both prior to and after weight and ethnicity adjustment.
Free beta hCG and PAPP-A significantly decreased with increasing maternal weight while nuchal translucency increased by a clinically insignificant amount. For free beta hCG the regression formula indicated that after accounting for maternal weight MoM values were 16% higher for African Americans, 6% higher for Asians and 9% lower for Hispanics compared to Caucasians (p < 0.001, p = 0.001, p < 0.001, respectively) but there was no significant difference for Asian Indians. For PAPP-A, MoM values were 35% higher for African Americans (p < 0.001) but were not significantly different for the other ethnic groups compared to Caucasians. Down syndrome false-positive rates did not vary with maternal weight prior to (p = 0.291) or after weight adjustment of biochemistry (p = 0.054). Trisomy 18 false-positive rates varied significantly with weight both before (OR = 1.455 per 20-pound increase, p < 0.001) and after (OR = 1.066 per 20-pound increase, p = 0.01) weight adjustment of biochemistry; however, the odds ratio was greatly reduced after weight adjustment.
CONCLUSION(S): The first-trimester screening markers, free beta hCG, PAPP-A and nuchal translucency vary with maternal weight and ethnicity. Adjustment of free beta hCG and PAPP-A is indicated but adjustment of nuchal translucency results may not be necessary.
估算孕早期筛查标志物的体重及种族校正因子。
利用51206例接受孕早期筛查患者的数据，针对不同体重队列（每20磅一组）计算特定种族的游离β-人绒毛膜促性腺激素（β-hCG）中位数倍数（MoM）、妊娠相关血浆蛋白A（PAPP-A）以及颈部透明带厚度差值（delta）。在进行体重和种族调整前后，分别评估唐氏综合征和18三体综合征的假阳性率。
随着孕妇体重增加，游离β-hCG和PAPP-A显著降低，而颈部透明带厚度虽有增加，但临床意义不大。对于游离β-hCG，回归公式表明，在考虑孕妇体重后，非裔美国人的MoM值比高加索人高16%，亚洲人高6%，西班牙裔低9%（p值分别<0.001、=0.001、<0.001），但印度裔亚洲人无显著差异。对于PAPP-A，非裔美国人的MoM值比高加索人高35%（p<0.001），但其他种族与高加索人相比无显著差异。在生化指标进行体重调整前（p=0.291）及调整后（p=0.054），唐氏综合征假阳性率均不随孕妇体重变化。18三体综合征假阳性率在生化指标体重调整前（每增加20磅，优势比=1.455，p<0.001）及调整后（每增加20磅，优势比=1.066，p=0.01）均随体重显著变化；然而，体重调整后优势比大幅降低。
孕早期筛查标志物游离β-hCG、PAPP-A和颈部透明带厚度随孕妇体重和种族而变化。游离β-hCG和PAPP-A需要进行调整，但颈部透明带厚度结果可能无需调整。
