Gjerris A C, Loft A, Pinborg A, Christiansen M, Tabor A
Department of Fetal Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
Ultrasound Obstet Gynecol. 2009 Jan;33(1):8-17. doi: 10.1002/uog.6254.
To determine the levels of first-trimester screening markers and to assess the false-positive rate for first-trimester combined screening for Down syndrome in a large national population of women pregnant after assisted reproductive technology (ART), in order to decide whether or not to correct risk calculation for mode of conception.
A national prospective cohort study of 1000 pregnancies achieved after ART was compared with a control group of 2543 pregnancies conceived spontaneously. All women completed a first-trimester combined screening program. Risk calculation was performed retrospectively based on the screening parameters to avoid bias due to the use of different algorithms of risk calculation.
In chromosomally normal pregnancies conceived after in-vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI), the pregnancy-associated plasma protein-A multiples of the median value was significantly decreased when compared with that of pregnancies conceived spontaneously (0.78 and 0.79 vs. 0.98), while there was no difference in the group treated by frozen embryo replacement. There was no difference in the level of free beta-human chorionic gonadotropin between groups. The median nuchal translucency thickness was smaller in the overall ART group compared with controls. The false-positive rate of first-trimester combined screening in the overall ART group, adjusted for maternal age, was significantly higher when compared with controls (9.0% vs. 6.0%).
It seems advisable to use a population of IVF/ICSI pregnancies to establish median curves for the first-trimester serum screening parameters and perhaps also for nuchal translucency thickness. However, care must be taken, as different ART treatment methods and aspects of medical history seem to alter the screening parameters in different ways.
在全国范围内大量接受辅助生殖技术（ART）后怀孕的女性群体中，确定孕早期筛查标志物水平，并评估孕早期唐氏综合征联合筛查的假阳性率，以决定是否校正受孕方式的风险计算。
对1000例ART后妊娠进行全国前瞻性队列研究，并与2543例自然受孕的对照组进行比较。所有女性均完成了孕早期联合筛查项目。基于筛查参数进行回顾性风险计算，以避免因使用不同风险计算算法而产生偏差。
在体外受精（IVF）和卵胞浆内单精子注射（ICSI）后染色体正常的妊娠中，与自然受孕的妊娠相比，妊娠相关血浆蛋白A中位数倍数显著降低（分别为0.78和0.79，自然受孕为0.98），而冷冻胚胎移植组之间无差异。各组间游离β-人绒毛膜促性腺激素水平无差异。总体ART组的颈项透明层厚度中位数低于对照组。在根据母亲年龄进行校正后，总体ART组孕早期联合筛查的假阳性率显著高于对照组（9.0%对6.0%）。
似乎可取的做法是使用IVF/ICSI妊娠群体来建立孕早期血清筛查参数以及可能的颈项透明层厚度的中位数曲线。然而，必须谨慎，因为不同的ART治疗方法和病史方面似乎以不同方式改变筛查参数。
