Antenatal Visits and Investigations MCQ — NEET PG Practice Question | NEETPGAI
Antenatal Visits and Investigations
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baby OBG
A 28-year-old primigravida at 20 weeks gestation attends her routine antenatal clinic visit. Regarding the investigations and assessments recommended at this gestational age, all of the following are standard EXCEPT:
A. Blood pressure measurement and urinalysis for proteinuria
B. Oral glucose tolerance test (OGTT) or fasting blood glucose for gestational diabetes screening
C. Detailed anatomical ultrasound (second-trimester scan) to assess fetal anatomy and placental location
D. Maternal serum screening using triple or quadruple marker test for chromosomal abnormalities
Explanation
Antenatal Investigations at 20 Weeks Gestation
Timing of Key Investigations in Pregnancy
Key Point
The 20-week visit is the second trimester milestone visit, with specific investigations appropriate to this gestational age. GDM screening is performed later (24–28 weeks), not at 20 weeks.
Screen for Down syndrome, Edwards syndrome, Patau syndrome
15–22 weeks
Blood pressure & urinalysis
Screen for hypertension, proteinuria, preeclampsia risk
Every visit
OGTT / fasting glucose
Screen for gestational diabetes mellitus
24–28 weeks
Why GDM Screening is NOT at 20 Weeks
High-YieldNEET PG
Gestational diabetes screening is performed at 24–28 weeks gestation, not at 20 weeks. This is the standard window across ICMR, WHO, and ACOG guidelines. Screening at 20 weeks is not recommended in routine low-risk pregnancies.
Mnemonic
GDSW = Gestational Diabetes Screening at Week 24–28 (not 20).
Clinical Pearl
Early fasting glucose at the first visit may identify pre-existing diabetes, but the formal OGTT for GDM is deferred to the second-trimester screening window (24–28 weeks) to allow adequate time for metabolic adaptation and to optimize sensitivity.
What IS Done at 20 Weeks
1.
Detailed fetal anatomy scan — assess all organ systems, rule out major structural defects
2.
Maternal serum screening — triple marker (AFP, hCG, uE3) or quadruple marker (adds inhibin A)
Options 0, 1, and 3 are all appropriate at 20 weeks. Option 2 (OGTT/fasting glucose for GDM) is NOT standard at this gestation — it belongs at 24–28 weeks.
Williams Obstetrics 26e Ch 9; ICMR Antenatal Care Guidelines; ACOG Practice Bulletin #229
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