Which finding best indicates advanced gestational age in a newborn?

• A. Increased hip flexion and adduction
• B. Hypertonia with hyperreflexia
• C. Poor rooting reflex
• D. Weak suck

Answer: (A)

Neonatal neuromuscular maturity is best judged by the level of tone and the posture the infant naturally assumes as gestation advances. More mature, later-gestation newborns exhibit increased flexor tone with the limbs drawn in, producing a posture where the hips are flexed and the thighs adducted. This flexed, tucked-in position reflects the overall motor system maturity that comes with longer intrauterine development, so increased hip flexion and adduction is a strong sign of advanced gestational age.

In contrast, hypertonia with hyperreflexia is not a normal feature of typical maturity and can indicate central nervous system abnormalities or pathology. A poor rooting reflex and a weak suck are signs of immaturity or neurologic compromise, more commonly seen in preterm infants or those with developmental concerns, rather than in healthy, more mature newborns.