Which of the following is an example of a newborn reflex?

Choice A rationale

The Babinski reflex is assessed by stroking the sole of the foot from the heel up and across the ball, which should cause the toes to curl downward (plantar flexion) in a normal infant. A positive Babinski sign in an adult (toes fanning out) indicates neurological impairment, but in a newborn, a transient fanning and dorsiflexion of the big toe is often a normal finding due to immature central nervous system myelination. This is not the reflex described.

Choice B rationale

The Glabellar reflex (or blink reflex) is elicited by gently tapping the newborn's forehead or glabella (the skin between the eyebrows). A positive response involves the newborn blinking in response to the tap. This is a brainstem-mediated, protective reflex that persists throughout life. It is tested to assess neurological integrity but is unrelated to the described startle reaction with arm and hand movements.

Choice C rationale

The Moro reflex, also known as the startle reflex, is a primitive reflex typically present from birth to about 6 months of age. It is triggered by a sudden loud noise or loss of head support. The characteristic response involves symmetrical abduction and extension of the arms, fanning of the fingers with the thumb and forefinger forming a 'C' shape, followed by adduction of the arms, sometimes accompanied by a tremor, exactly as described.

Choice D rationale

The Tonic neck reflex (or fencing posture) is observed when the infant's head is turned quickly to one side while they are supine. The reflex involves the arm and leg on the side to which the head is turned extending, and the opposite arm and leg flexing. This is a different, posture-regulating reflex, unrelated to the sudden startle response described by the nurse.

Choice A rationale

The primary mechanism for preventing postpartum hemorrhage, which is a major risk following any birth including cesarean, is effective uterine contraction (involution). Postpartum hemorrhage is defined as blood loss greater than 1000 mL. Assessing the uterus for firmness (contraction) every 15 minutes in the immediate recovery phase confirms that the myometrial muscle fibers are constricting the uterine blood vessels at the placental site, which is the most critical intervention to prevent excessive bleeding.

Choice B rationale

Monitoring urinary output is essential for assessing renal perfusion and hydration status, and a decrease in output can be an indicator of hypovolemic shock secondary to hemorrhage, but it is not the primary direct assessment for the source of the hemorrhage. The nurse must first assess the fundus to prevent the hemorrhage itself. Normal urinary output is ≥ 30 mL/hr.

Choice C rationale

Assessing the abdominal dressings is necessary to monitor for incisional bleeding, which is a local complication. However, the most life-threatening source of hemorrhage after cesarean birth, like vaginal birth, remains at the placental implantation site inside the uterus. Therefore, the fundal assessment takes precedence over the dressing check for hemorrhage risk.

Choice D rationale

Maintaining a peripheral intravenous infusion (IV) is a standard measure to ensure intravascular access for fluid resuscitation or medication administration (e.g., oxytocin). While important for supportive care, maintaining a specified infusion rate of 100 mL/hr is a therapeutic action, not an assessment for hemorrhage. The primary assessment remains the firm contraction of the uterine muscle.