my CGC

Prenatal Screening

Knowing clinical information about the baby, as quickly as possible, is the desire of any pregnant woman.

2-3% of babies are born with several development anomalies that may be a result of chromosomal alterations, congenital malformations, genetic diseases or caused by extern agents (as infections or pharmaceutics). Prenatal screening detects high risk pregnancies for some chromosome abnormalities.

CGC Genetics developed an Early Prenatal Combined Screening:

Nowadays, 1st trimester screening is considered to be the best prenatal screening approach for Down syndrome (trisomy 21), with high detection rates (90 to 97%) and a reduced false positive rate (3 to 5%). This test includes biochemical parameters (free ß-hCG and PAPP-A) and ultrasound markers (nuchal translucency and fetal nasal bone). This test also evaluates risk for Trisomy 18 and Trisomy 13.

1. Blood sample for biochemical analysis (filter card):

Performed between week 9 and 12 (preferentially at week 9 and 10). The discriminative power of PAPP-A, between regular and irregular values, is higher in this gestation period, increasing the detection capacity. The biochemical result is retained until reception of the ultrasound data.


2. Ultrasound for nuchal translucency evaluation (NT):

Performed between week 11 and 12. Period of time in which NT has more discriminative power between regular and irregular parameters. With this screening approach it is possible to obtain the most accurate results for each marker used, at an early pregnancy stage.


2 nd Trimester Prenatal Screening

A blood sample (filter card), performed between week 14 and 22 of gestation, is used for biochemical analysis of Alpha-fetoprotein (AFP) and free Human Chorionic Gonadotropin (free β-hCG). Prenatal Screening during 2nd Trimester detects more than 98% of anencephalic babies, 90% of spina bifida cases and 80% of Down syndrome and Trisomy 18.

Please not that a lower risk in Prenatal Screening tests does not exclude Down syndrome, Trisomy 18 or other chromosomal alterations, congenital defects, mental retardation or disorders by Prenatal screening test, only indicates a lower risk for these conditions.

If you have any questions, please don´t hesitate to contact us or your physician.