Related Experiment Video
Updated: Jan 30, 2026

Semiconductor Sequencing for Preimplantation Genetic Testing for Aneuploidy
Published on: August 25, 2019
Reference centile charts of first-trimester aneuploidy screening & Doppler parameters for Indian population
Manisha Kumar1, Shalini Singh2, Karuna Sharma3
1Department of Obstetrics & Gynecology, Lady Hardinge Medical College, New Delhi, India.
Background & Objectives:
The risk estimation for foetal aneuploidies in the first trimester of pregnancy uses reference curves based on western data. The objective of this study was to construct the reference curves of first-trimester foetal aneuploidy screening parameters for the Indian women.
Methods:
: Cross-sectional data were obtained from 1204 singleton pregnancies between the crown-rump length (CRL) of 40-84 mm. Linear regression models were constructed; the mean, median and standard deviation were derived as a function of CRL.
Results:
The mean value of CRL was 61.3 mm. The regression analysis showed a significant correlation between all variables and CRL (P< 0.001). There was a positive correlation of CRL with nuchal translucency (NT) (y=0.010x+0.629, R2=0.116) and pregnancy-associated plasma protein-A (PAPP-A) (y=0.107x-1.079, R2=0.173), whereas inverse correlation was seen with free β-human chorionic gonadotropin (β-hCG) (y=-0.409x+75.025, R2=0.018) and Doppler parameters pulsatility index (PI) (y=-0.008x+1.924 R2=0.053). The centile charts of NT, PAPP-A, free β-hCG and uterine artery (Ut A) Doppler PI were constructed.
Interpretation & Conclusions:
The reference centile charts of first trimester aneuploidy screening along with Doppler parameters were derived in Indian pregnant women. These centile charts may be used as a reference for clinical use in Indian population.
Related Concept Videos
Distributions to Estimate Population Parameter
Run Charts
The R Chart
R charts are pivotal for pinpointing shifts in process variability. Stability is indicated when all data points remain within the defined upper and lower...
Pareto Chart
The Pareto chart is named after the Italian economist Vilfredo Pareto, who described the Pareto...
Interpreting R Charts
An R chart plots the range of subsets of measurements collected from a process. Each point on the chart represents the range—defined as the difference between the maximum and minimum...
Doppler Effect - I

