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 of gestation attends her routine antenatal clinic visit. During the anomaly scan, a single umbilical artery is noted incidentally. Which is the most common congenital anomaly associated with single umbilical artery?
A. Renal agenesis
B. Neural tube defects
C. Cleft palate
D. Cardiac defects
Explanation
Single Umbilical Artery (SUA) and Associated Anomalies
Overview
Key Point
Single umbilical artery occurs in 0.5–1% of singleton pregnancies and is associated with congenital anomalies in 20–40% of cases.
Most Common Associated Anomalies
Table
Anomaly
Frequency
Clinical Significance
Renal agenesis / dysplasia
30–40%
Most common; bilateral agenesis incompatible with life
Cardiac defects
20–25%
VSD, ASD, TOF, PDA
GI anomalies
10–15%
Duodenal atresia, tracheo-esophageal fistula
CNS anomalies
5–10%
Anencephaly, spina bifida
Limb anomalies
5–10%
Polydactyly, syndactyly
Pathophysiology
High-YieldNEET PG
The umbilical artery develops from the paired dorsal aortae. Regression of one artery occurs early in embryogenesis (weeks 4–8), suggesting a developmental insult during this critical window. This timing correlates with organogenesis, explaining the high association with renal and cardiac anomalies.
Clinical Pearl
Key Point
Isolated SUA (without other anomalies on detailed ultrasound) carries a lower risk of adverse outcome (~10–15%), but detailed fetal anatomy survey and postnatal renal ultrasound are mandatory.
