Mooney R A, Arvan D A, Saller D N, French C A, Peterson C J
Department of Pathology, University of Rochester Medical Center, New York, USA.
Obstet Gynecol. 1995 Dec;86(6):900-5. doi: 10.1016/0029-7844(95)00308-e.
To investigate the preliminary observation that primigravid women have higher hCG multiples of the median (MoM) than multigravid women.
An analysis of the effect of gravidity and parity on maternal serum alpha-fetoprotein (MSAFP) and hCG was performed using data from 20,009 consecutive singleton pregnancies of 15-20 weeks' gestation in a maternal serum screening program.
The human chorionic gonadotropin MoM for primigravid women was 0.1 MoM higher than for multigravid women. As parity or gravidity increased, maternal serum hCG decreased. The median hCG MoM for nulliparous women was 1.05, compared with 0.94 MoM for para 3 women. The decrease in hCG was similar at each gestational week from 15-20. In contrast, MSAFP and MSAFP MoM were unaffected by parity. Maternal age and race were potential contributing factors to the effect of parity. However, the decrease in hCG MoM with parity was observed within each 5-year increment of maternal age. Similarly, both black and non-black populations displayed decreases in hCG with parity, although black women had a consistently higher MoM in all matched sets. The decrease in hCG MoM with parity was also observed in 50 Down syndrome cases. Correcting patient data for parity resulted in the hCG MoM changing only 2.7% on average. The detection rate for the 50 Down syndrome cases would not have changed.
The decrease in maternal serum hCG with increasing parity demonstrates that pregnancy history influences the level of maternal serum hCG. Further studies are needed to define the contributing factors, but the impact of parity on Down syndrome screening appears to be small.
调查初产妇血清人绒毛膜促性腺激素（hCG）中位数倍数（MoM）高于经产妇这一初步观察结果。
利用一项孕中期血清学筛查项目中20009例连续单胎妊娠（孕15 - 20周）的数据，分析孕次和产次对母血清甲胎蛋白（MSAFP）和hCG的影响。
初产妇的hCG MoM比经产妇高0.1 MoM。随着产次或孕次增加，母血清hCG降低。未产妇的hCG MoM中位数为1.05，而经产3次的妇女为0.94 MoM。在孕15至20周的每个孕周，hCG的下降情况相似。相比之下，MSAFP及其MoM不受产次影响。母亲年龄和种族是产次影响的潜在因素。然而，在母亲年龄每增加5岁的范围内，均观察到hCG MoM随产次下降。同样，黑人和非黑人人群中hCG均随产次下降，尽管在所有匹配组中黑人妇女的MoM始终较高。在50例唐氏综合征病例中也观察到hCG MoM随产次下降。校正产次后的患者数据，hCG MoM平均仅改变2.7%。50例唐氏综合征病例的检出率不会改变。
母血清hCG随产次增加而降低，表明妊娠史会影响母血清hCG水平。需要进一步研究以确定其影响因素，但产次对唐氏综合征筛查的影响似乎较小。
