Screening for fetal trisomy 21 in the first trimester of pregnancy: maternal serum free β-hCG and fetal nuchal translucency thickness

Introduction. Aneuploidies are the major cause of perinatal death and early psychophysical disorders. Objective. In this study, we analyzed detection and false-positive rates of screening for aneuploidies in the first trimester by the combination of maternal age, fetal nuchal translucency (NT) thickness and maternal serum free beta-human chorionic gonadotrophin (?-hCG), and pregnancy-associated plasma protein-A (PAPP-A) at 11-13+6 weeks of gestation, using the appropriate software developed by the Fetal Medicine Foundation. Methods. Our screening study for aneuploidies analyzed 4172 singleton pregnancies from January 2006 to December 2010. The sensitivities and false-positive rates using the combined aneuploidies determination for the risk cut-off of 1:275 were evaluated. Results. In the trisomy 21 pregnancies, the fetal NT was higher than 95th centile, in 72.8%, serum free b-hCG concentration it was above the 95th centile in 55% and serum PAPP-A was below the 5th centile in 47% of the cases. In the trisomy 18 and 13, the fetal NT was above 95th centile in 66.6% and 44.4% of the cases, respectively. The serum free b-hCG concentration was above the 95th centile in 0 and 10%, but serum PAPP-A was below 5th centile in 80.9% and 88.8% of pregnancies. In the trisomy 21 pregnancies the median free beta-hCG was 2.3 MoM and the median PAPP-A was 0.45 MoM. Chromosomal abnormalities were detected in 169 fetuses: trisomy 21 (97), Turner syndrome (19), trisomy 18 (28), trisomy 13 (11) and others (14). Detection rate of combined screening for aneuploides were 86.0% with false positive rate of 5.3% (mean age 33?4.9 years, >35 years in 35% of pregnancies). Conclusion. Our study suggests that the strategy of first-trimester combined screening of biochemical values and ultrasonographic parameters at 12 gestational weeks identifies higher percentage of aneuploidies with a lower false-positive rate than a single parameter strategy.

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First trimester prenatal diagnosis of trisomy 21 in discordant twins using fetal nuchal translucency thickness and maternal serum free ?-hCG and PAPP-A

Prenatal Diagnosis ◽

10.1002/1097-0223(200008)20:8<683::aid-pd847>3.0.co;2-m ◽

2000 ◽

Vol 20 (8) ◽

pp. 683-684 ◽

Cited By ~ 13

Author(s):

Kevin Spencer ◽

Kypros H. Nicolaides

Keyword(s):

Prenatal Diagnosis ◽

Trisomy 21 ◽

First Trimester ◽

Nuchal Translucency ◽

Maternal Serum ◽

Serum Free ◽

Discordant Twins

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First-trimester screening for chromosomal abnormalities by integrated application of nuchal translucency, nasal bone, tricuspid regurgitation and ductus venosus flow combined with maternal serum free β-hCG and PAPP-A: a 5-year prospective study

Ultrasound in Obstetrics and Gynecology ◽

10.1002/uog.10051 ◽

2012 ◽

Vol 39 (5) ◽

pp. 528-534 ◽

Cited By ~ 21

Author(s):

S. R. Ghaffari ◽

A. R. Tahmasebpour ◽

A. Jamal ◽

S. Hantoushzadeh ◽

L. Eslamian ◽

...

Keyword(s):

Chromosomal Abnormalities ◽

Nasal Bone ◽

First Trimester ◽

Nuchal Translucency ◽

Maternal Serum ◽

Ductus Venosus ◽

First Trimester Screening ◽

Serum Free ◽

Trimester Screening ◽

Β Hcg

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Stability of maternal serum free β-hCG following whole blood sample transit: First trimester Down’s syndrome screening in Scotland

Annals of Clinical Biochemistry International Journal of Laboratory Medicine ◽

10.1177/00045632211045250 ◽

2021 ◽

pp. 000456322110452

Author(s):

Angela Ballantyne ◽

Lorna Rashid ◽

Rebecca Pattenden

Keyword(s):

Transit Time ◽

Down's Syndrome ◽

Down’S Syndrome ◽

First Trimester ◽

Maternal Serum ◽

Dependent Manner ◽

Serum Free ◽

Β Hcg ◽

In Transit ◽

The Impact

Background Maternal serum free beta human chorionic gonadotrophin (free β-hCG) is used as a biomarker in first trimester screening for fetal Down’s syndrome. Production of free β-hCG can occur in vitro in a time- and temperature-dependent manner; thus, the current Scottish screening protocol states samples must be received by the laboratory within 72 h. To assess the validity of the protocol, an audit was conducted to determine the impact of transit time on maternal serum free β-hCG multiple of median (MoM) values in the Scottish screened population. Methods Corrected MoM values from antenatal screening carried out over one year (April 2017 to March 2018) were stratified according to sample transit time and compared. To investigate possible environmental temperature effects, the data were split according to season and maternal serum free β-hCG concentrations from summer and winter compared. Results Of the 28,368 samples included in the study, 24,368 were received on the day of phlebotomy or after one day in transit. Only 1.5% of samples were received after 3 days in transit. The difference in maternal serum free β-hCG MoM values due to transit time was not significant. No statistical difference was found between maternal serum free β-hCG concentrations from samples collected in summer and winter months. Conclusion The current sample receipt protocol in use by the Scottish Down’s syndrome screening programme is fit for purpose.

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