When can these tests be performed?

Ultrasound: Anytime during pregnancy.
First Trimester Screening: Between 11 and 13 weeks (ideally at 12 weeks); accompanied by ultrasound measurements.
Second Trimester Screening: Between 15 and 20 weeks; accompanied by ultrasound measurements.
NIPT (placental-fetal DNA) Screening: Anytime after 10 weeks.
Chorionic Villi Sampling (CVS): Between 10 and 13 weeks.
Routine Amniocentesis: Most commonly between 16 and 20 weeks.