Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, The Prince of Wales Hospital, Shatin, Hong Kong SAR, China.
Ultrasound Obstet Gynecol. 2009 Apr;33(4):387-93. doi: 10.1002/uog.6340.
To establish normative values and distribution parameters of first-trimester maternal serum free beta-human chorionic gonadotropin (beta-hCG), pregnancy-associated plasma protein-A (PAPP-A) and fetal nuchal translucency (NT) thickness in Chinese women and to examine the effects of covariates on their levels.
Maternal serum free beta-hCG, PAPP-A and fetal NT were measured in 9762 women presenting for first-trimester combined screening for Down syndrome at 11 to 14 weeks of gestation. Individuals' markers were converted to multiples of the median (MoM) using expected medians estimated by performing a weighted regression analysis. Multivariate regression analysis was performed to assess the influence of maternal weight, parity, ethnicity, chorionicity in twin pregnancies, smoking, insulin-dependent diabetes and mode of conception on individual marker MoM levels.
Both free beta-hCG and PAPP-A median values demonstrated an exponential relationship with gestational age in days. Multivariate regression analysis indicated that free beta-hCG MoM was statistically significantly dependent on maternal weight (P < 0.0001) and chorionicity in twin pregnancy (both monochorionic and dichorionic P < 0.0001), that PAPP-A MoM was dependent on maternal weight (P < 0.0001), parity (P < 0.0001), chorionicity in twin pregnancy (both monochorionic and dichorionic P < 0.0001) and mode of conception (P = 0.002), and that fetal NT-MoM was dependent on maternal weight (P = 0.0006) and mode of conception (P = 0.012).
Normative values have been generated to allow conversion of NT, free beta-hCG and PAPP-A to their MoM equivalents and correction factors have been determined to adjust for maternal and pregnancy characteristics for use in ethnic Chinese women undergoing first-trimester screening for aneuploidy.
建立中国孕妇早孕期母血清游离β-人绒毛膜促性腺激素（β-hCG）、妊娠相关血浆蛋白 A（PAPP-A）和胎儿颈项透明层（NT）厚度的参考值范围和分布参数，并探讨协变量对其水平的影响。
对 9762 例孕 11～14 周行早孕期唐氏综合征联合筛查的孕妇进行母血清游离β-hCG、PAPP-A 和胎儿 NT 检测。采用加权回归分析估计预期中位数，将个体标志物转换为中位数倍数（MoM）。采用多元回归分析评估孕妇体重、产次、种族、双胎绒毛膜性、吸烟、胰岛素依赖型糖尿病和受孕方式对个体标志物 MoM 水平的影响。
游离β-hCG 和 PAPP-A 中位数均与孕龄（天）呈指数关系。多元回归分析表明，游离β-hCG MoM 与孕妇体重（P<0.0001）和双胎绒毛膜性（均为单绒毛膜和双绒毛膜，P<0.0001）显著相关，PAPP-A MoM 与孕妇体重（P<0.0001）、产次（P<0.0001）、双胎绒毛膜性（均为单绒毛膜和双绒毛膜，P<0.0001）和受孕方式（P=0.002）显著相关，胎儿 NT-MoM 与孕妇体重（P=0.0006）和受孕方式（P=0.012）显著相关。
本研究建立了适用于中国孕妇的早孕期 NT、游离β-hCG 和 PAPP-A 的参考值范围和校正因子，以调整孕妇和妊娠的特征，用于唐氏综合征的早孕期筛查。
