When is maternal serum testing typically performed?

When is maternal serum testing typically performed?

• A. 10-14 weeks
• B. 15-20 weeks
• C. 21-26 weeks
• D. 27-32 weeks

Answer: (B)

Maternal serum screening is done in mid-pregnancy, typically around 15–20 weeks gestation. This is when the common serum markers (such as AFP, hCG, estriol, and sometimes inhibin-A) provide the most informative patterns for assessing risk of neural tube defects and chromosomal conditions like Down syndrome and trisomy 18. The timing balances accuracy with the ability to act on results; earlier screening uses different markers, while later testing is less informative. If the screen suggests elevated risk, diagnostic options like amniocentesis or CVS may be discussed.

Maternal serum screening is done in mid-pregnancy, typically around 15–20 weeks gestation. This is when the common serum markers (such as AFP, hCG, estriol, and sometimes inhibin-A) provide the most informative patterns for assessing risk of neural tube defects and chromosomal conditions like Down syndrome and trisomy 18. The timing balances accuracy with the ability to act on results; earlier screening uses different markers, while later testing is less informative. If the screen suggests elevated risk, diagnostic options like amniocentesis or CVS may be discussed.