Department of Obstetrics, Amsterdam Reproduction and Development Research Institute, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.
Department of Medical Biology, Section Clinical Anatomy & Embryology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.
Prenat Diagn. 2021 Dec;41(13):1685-1693. doi: 10.1002/pd.6054. Epub 2021 Oct 8.
In this era of non-invasive-prenatal testing (NIPT), when dating scans are usually performed around 10 weeks of gestation, an increased NT before the official established timeframe (CRL between 45 and 84 mm) may be encountered. Information on management of these pregnancies is limited. Therefore, we evaluated the relationship between an early increased NT and adverse pregnancy outcome. Secondary, we evaluated the rate of chromosomal anomalies that might have been missed in first trimester should solely NIPT be performed as first-tier test, and the rate of adverse pregnancy outcome if NT normalizes before 14 weeks.
We performed a retrospective cohort study that included all pregnancies between January 1, 2007 and June 1, 2020 in Amsterdam UMC locations AMC and VUmc. We included fetuses with a crown-rump length (CRL) < 45 mm (∼11 weeks) and a nuchal translucency (NT) measurement ≥2.5 mm. Fetuses referred with an early increased NT and a major fetal anomaly at the dating scan were excluded, as were cases of parents with a family history of monogenetic disease(s) or recognized carriers of a balanced translocation.
We included 120 fetuses of which 66.7% (80/120) had an adverse pregnancy outcome. Congenital anomalies were present in 56.7% (68/120), 45.8% (55/120) had a chromosomal anomaly. The prevalence of congenital anomalies was 30.3% in fetuses with NT 2.5-3.4 mm compared to 66.7% with NT ≥ 3.5 mm (p < 0.001). 16.7% (20/120) had a chromosomal anomaly that might have been missed by conventional NIPT in first trimester. We found an adverse pregnancy outcome of 24% in the group with a normalized NT compared to 78.1% in the group with a persistently increased NT (p < 0.001).
An early increased NT should make the sonographer alert. In this selected cohort, an early increased NT was associated with a high probability of having an adverse pregnancy outcome. Regardless of CRL, we deem that an early increased NT ≥ 3.5 mm warrants referral to a Fetal Medicine Unit for an extensive work-up. NT normalization seems favorable, but a prospective study should define the appropriate work-up for NT in the lower range (2.5-3.4 mm).
在无创产前检测（NIPT）时代，当通常在妊娠 10 周左右进行超声检查时，可能会遇到在官方规定的时间范围之前（CRL 在 45 至 84 毫米之间）增大的颈项透明层（NT）。关于这些妊娠管理的信息有限。因此，我们评估了早期增大的 NT 与不良妊娠结局之间的关系。其次，我们评估了如果仅将 NIPT 作为一线检测，在第一孕期可能会错过的染色体异常的发生率，以及在 14 周之前 NT 正常化的不良妊娠结局的发生率。
我们进行了一项回顾性队列研究，纳入了 2007 年 1 月 1 日至 2020 年 6 月 1 日在阿姆斯特丹 UMC 地点 AMC 和 VUmc 的所有妊娠。纳入了 CRL<45 毫米（约 11 周）和 NT 测量值≥2.5 毫米的胎儿。排除了在约会扫描时因早期增加的 NT 和主要胎儿异常而转诊的胎儿，以及父母有单基因疾病家族史或已知平衡易位携带者的病例。
我们纳入了 120 例胎儿，其中 66.7%（80/120）有不良妊娠结局。先天性异常占 56.7%（68/120），45.8%（55/120）存在染色体异常。NT 为 2.5-3.4 毫米的胎儿先天性异常的发生率为 30.3%，而 NT≥3.5 毫米的胎儿为 66.7%（p<0.001）。在第一孕期常规 NIPT 可能会错过 16.7%（20/120）的染色体异常。我们发现，NT 正常化组的不良妊娠结局为 24%，而持续增加 NT 组的不良妊娠结局为 78.1%（p<0.001）。
早期增大的 NT 应该引起超声医师的警惕。在这个选定的队列中，早期增大的 NT 与不良妊娠结局的可能性较高相关。无论 CRL 如何，我们认为早期增大的 NT≥3.5 毫米需要转诊到胎儿医学科进行广泛检查。NT 正常化似乎有利，但前瞻性研究应确定 NT 在较低范围（2.5-3.4 毫米）的适当检查。
