How many weeks into pregnancy should one do the Tissue Screening for Chromosomal Abnormalities?

Patient's question:

April 6th was the last menstrual period

Doctor's answer:

It is recommended to have a 4D ultrasound between 22 weeks and 30 weeks, as this stage allows for more complete fetal development, clearer amniotic fluid, and thus the maximum extent of anomaly screening. At 4 months, you can have a prenatal screening test for anomalies.
4D ultrasound is more advanced than regular ultrasound, making anomaly screening more accurate. Generally, doctors advise patients with risk factors for prenatal complications to maintain a balanced diet, avoid spicy and stimulating foods, and stay away from cold foods. Additionally, patients should create an environment that promotes emotional stability and stress relief. Wishing you a healthy delivery.