How many months into pregnancy can Down syndrome screening be performed?

Generally, pregnant women can undergo Down syndrome screening between 15 to 20 weeks of pregnancy. Detailed analysis is as follows:

Down syndrome screening performed at 15-16 weeks of pregnancy ensures relatively stable fetal development indicators and suitable concentrations of serum biomarkers for testing. Combining gestational age, maternal age, and other information to calculate the risk value provides higher accuracy. Some pregnant women with irregular menstrual cycles may have errors in calculating gestational age and can undergo screening around 15 weeks to facilitate adjustment and evaluation in combination with subsequent ultrasound results.

Down syndrome screening conducted at 18-20 weeks falls in the later part of the screening window, where serum biomarker concentrations remain within the effective detection range. If high risk is detected at this stage, there will be sufficient time to arrange further diagnostic tests, avoiding time constraints that may affect subsequent interventions.

Before undergoing Down syndrome screening, it is necessary to confirm the gestational age and follow medical advice to complete the examination within the recommended timeframe. After receiving the results, promptly consult a doctor for interpretation and clarification of the next steps in management.