First-trimester combined screening is effective for the detection of unbalanced chromosomal translocations at 11 to 12 weeks of gestation

Current Perspectives of Prenatal Cell-free DNA Screening in Clinical Management of First-Trimester Septated Cystic Hygroma

First-trimester septated cystic hygroma occurs in approximately 1 in 268 pregnancies and has long been associated with a markedly increased risk of fetal aneuploidy and, among euploid fetuses, an increased risk of structural anomalies primarily affecting the cardiac and skeletal systems. Invasive prenatal diagnosis – chorionic villus sampling and/or amniocentesis – encompasses the time-honored clinical tools for the next step in management following prenatal sonographic diagnosis of first-trimester septated cystic hygroma. Currently, prenatal cell-free DNA (cfDNA) screening for fetal aneuploidy with select microdeletions is gradually replacing the considerably less sensitive, and labor-intensive combined first-trimester screening. These new technologies have opened potential new venues in the clinical management of this ominous late first-trimester sonographic diagnosis. Advances in cfDNA technologies are now permitting detection of chromosomal copy number variants (CNV) larger than 7Mb across genome and select serious single-gene disorders (mainly impacting skeletal and neurological development), affecting quality of life and may benefit from medical and/or surgical management. This commentary will address the available non-invasive prenatal screening technologies, which clearly enhance immediate genetic analysis modalities applicable in the presence of the complex sonographic finding of first-trimester septated cystic hygroma.

Strategy for Use of Genome-Wide Non-Invasive Prenatal Testing for Rare Autosomal Aneuploidies and Unbalanced Structural Chromosomal Anomalies

Atypical fetal chromosomal anomalies are more frequent than previously recognized and can affect fetal development. We propose a screening strategy for a genome-wide non-invasive prenatal test (NIPT) to detect these atypical chromosomal anomalies (ACAs). Two sample cohorts were tested. Assay performances were determined using Cohort A, which consisted of 192 biobanked plasma samples—42 with ACAs, and 150 without. The rate of additional invasive diagnostic procedures was determined using Cohort B, which consisted of 3097 pregnant women referred for routine NIPT. Of the 192 samples in Cohort A, there were four initial test failures and six discordant calls; overall sensitivity was 88.1% (37/42; CI 75.00–94.81) and specificity was 99.3% (145/146; CI 96.22–99.88). In Cohort B, there were 90 first-pass failures (2.9%). The rate of positive results indicating an anomaly was 1.2% (36/3007) and 0.57% (17/3007) when limited to significant unbalanced chromosomal anomalies and trisomies 8, 9, 12, 14, 15, 16, and 22. These results show that genome-wide NIPT can screen for ACAs with an acceptable sensitivity and a small increase in invasive testing, particularly for women with increased risk following maternal serum screening and by limiting screening to structural anomalies and the most clinically meaningful trisomies.

Relationship Between Pregnancy Complications and Serum Pregnancy Associated-Plasma-Protein-A and Free-β-Human Chorionic Gonadotropin in the First Trimester Among Iranian Women

Objective: To evaluate the relationship between maternal serum levels of pregnancy-associated-plasma-protein-A (PAPP-A) and β-human-chorionic-gonadotropin (β-hCG) and pregnancy complications. Materials and methods: This is a case-control study conducted during 2015- 2016. Women at their first pregnancy were enrolled and serum PAPP-A and free-β-hCG were measured in 9-14 weeks of gestation. They were followed till the end of pregnancylooking for complications including preterm labor, pregnancy induced hypertension (PIH), abortion, and intra-uterine growth retardation (IUGR). Results: A total of 1070 pregnant women (mean age: 28.64 ± 4.95 years) were enrolled. Low serum levels of PAPP-A were more frequent in patients developing IUGR (17.4% versus 1.2%, p < 0.001), preterm labor (13% versus 2%, p = 0.013), and PIH (17.4% versus 4%, p = 0.015) compared those without complications. The serum levels of free-β-hCG were not different in patients with and without complications (p > 0.05). Conclusion: There is an association between low serum levels of PAPP-A and developing IUGR, preterm labor, and PIH.