A postpartum woman has a quad screen with a maternal serum (MSAFP) lower than normal. What diagnosis can be expected for the newborn?

A lower-than-normal maternal serum alpha-fetoprotein (MSAFP) level on a quad screen is often associated with the risk of certain chromosomal abnormalities, most notably trisomy 21, also known as Down syndrome. The quad screen measures several markers in a pregnant woman's blood, and low levels of MSAFP, combined with other markers, can indicate an increased risk for this condition.

Trisomy 21 occurs when there is an extra copy of chromosome 21, leading to developmental delays and characteristic physical features. The strong link between low MSAFP levels and an increased likelihood of trisomy 21 is well-supported by research and clinical findings, making it an expected diagnosis in the context of low MSAFP results.

Conversely, other conditions listed, such as neural tube defects, typically are associated with elevated MSAFP levels, not lower. Conditions related to gestational age or macrosomia do not have a direct correlation with MSAFP Screening that would indicate risk; hence, they are less likely to be a correct interpretation in this scenario. Understanding the implications of the quad screen helps healthcare providers counsel patients regarding potential outcomes and necessary follow-up testing.