First trimester screening is performed during the first 9-13 weeks of pregnancy. It is a non-invasive test used to determine if your baby is at an increased risk for certain chromosomal disorders, including Down syndrome, trisomy 18 or trisomy 13.
Follow the instructions given by your healthcare provider.
A first trimester screening typically takes 30-45 minutes.
The screening consists of a blood test and ultrasound exam. The blood test is taken between the gestational age of 9 weeks to 13 weeks, 6 days. The ultrasound exam is scheduled between 11 weeks to 13 weeks. 6 days.
During the blood test, a finger stick is performed to obtain a blood sample. The sample is applied to a special card and sent to a lab for analysis of two chemicals: free Beta human chorionic gonadotropin (free Beta), and pregnancy associated plasma protein-A (PAPP-A) which are normally found in the blood of all pregnant women.
The ultrasound exam records a fetal heartbeat and determines gestational age. The amount of fluid accumulation behind the neck of the baby, called nuchal translucency (NT), is also measured.
First trimester screening has been extensively studied and proven to detect 91% of Down syndrome pregnancies, and 95% of trisomy 18/13 pregnancies.
The data from the ultrasound exam will also be sent to the lab. The lab will combine the ultrasound data and the blood test data to estimate a specific risk for Down syndrome and trisomy 18 and trisomy 13.
The findings will be sent to your healthcare provider who will then contact you to discuss the results.