During a prenatal check-up at 16 weeks of gestation, a pregnant client's blood test shows elevated levels of maternal serum alpha-fetoprotein (MSAFP). This finding is most indicative of which potential fetal condition?

1. A

   Down syndrome

2. B

   Gestational diabetes

3. C

   Preeclampsia

4. D

   Neural tube defect

Appeared in: NORCET-6 mains-2024

Explanation

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• Elevated MSAFP is most strongly associated with open neural tube defects such as spina bifida and anencephaly.
• AFP leaks into maternal serum when there is a defect in the fetal neural tube or abdominal wall.
• Screening is performed between 15 and 20 weeks; a value above 2.0 or 2.5 MoM is considered elevated.
• Nearly all cases of anencephaly and many cases of spina bifida are detected by elevated MSAFP.
• Other causes of elevated MSAFP include incorrect gestational age, multiple gestation, and fetal demise, but neural tube defect is the most clinically significant.

Why Other Options Were Wrong

• Option A: Down syndrome is typically associated with decreased (not elevated) MSAFP levels on second-trimester screening.
• Option B: Gestational diabetes is not detected or indicated by MSAFP levels. Diagnosis relies on glucose tolerance testing.
• Option C: Preeclampsia is not associated with elevated MSAFP. It is diagnosed based on hypertension and proteinuria after 20 weeks gestation.

Related Visual

Clinical Relevance

• Nursing practice connection: Use the key finding related to Interpretation of elevated maternal serum alpha-fetoprotein (MSAFP) in pregnancy to guide bedside assessment, documentation, and the next nursing action.
• Nurses play a key role in counseling pregnant women about the purpose and implications of MSAFP screening.
• Early detection of neural tube defects allows for timely counseling, further diagnostic testing, and multidisciplinary planning for delivery and neonatal care.
• What if? If MSAFP is low instead of high, the nurse should consider the possibility of chromosomal abnormalities such as Down syndrome and ensure appropriate follow-up.

How to Approach the Question

• Identify the key laboratory finding (elevated MSAFP) and the gestational age (16 weeks).
• Recall the main fetal conditions associated with elevated MSAFP, focusing on neural tube defects.
• Eliminate options that are not linked to MSAFP changes (e.g., gestational diabetes, preeclampsia).
• Use knowledge of prenatal screening protocols to select the most likely fetal condition indicated by the abnormal result.
• For similar questions, always match the specific marker (e.g., AFP, hCG, estriol) to the condition it screens for.

Concept Tested & Keywords

• Concept Tested: Interpretation of elevated maternal serum alpha-fetoprotein (MSAFP) in pregnancy
• Stem keywords: prenatal check-up, 16 weeks gestation, elevated maternal serum alpha-fetoprotein, blood test
• Lead-in keywords: most indicative of, potential fetal condition
• Clinical cues: Elevated MSAFP at 16 weeks is a key marker for open fetal defects

Question ID

QvrxYtUMn3GaJlYExrpfIs

Copy ID

Reference Book

E6 Obstetrics Williams p. 29-48

E6 Pathology-Vandana Puri & Kavita Gaur Textbook of Pathology and Genetics p. 537-539