In a prolonged delivery, an abnormal Moro reflex in the newborn may be caused by:

NORCET 7 Prelims -2024

Obstetrics & Gynaecology

Hard

Appeared in: NORCET 7 Prelims -2024

Explanation

A prolonged delivery can lead to complications like umbilical cord compression or reduced placental blood flow, causing fetal distress.
Fetal distress results in a lack of oxygen and blood flow to the brain, a condition known as birth asphyxia or hypoxic-ischemic encephalopathy (HIE).
HIE causes central nervous system (CNS) depression and damage to brain cells.
This CNS depression manifests as hypotonia (poor muscle tone) and the suppression of primitive reflexes, such as an abnormal or absent Moro reflex.

Option B: Maternal hypertension is a chronic condition and a risk factor that can compromise the fetus before labor. It does not directly result from a prolonged delivery itself.
Option C: Placental insufficiency is generally a chronic issue that develops during pregnancy, reducing the fetus's tolerance to labor stress. The acute event causing the neurological sign is the asphyxia that occurs during the prolonged delivery.
Option D: Prematurity is defined by gestational age (born before 37 weeks). While premature infants may have an immature or weak Moro reflex, this condition is not caused by the duration of the delivery.

Visual 1: Diagram illustrating the mechanism of birth asphyxia, showing how umbilical cord compression during a prolonged delivery can cut off oxygen supply to the fetus.
Visual 2: Infographic comparing a normal Moro reflex (symmetric arm abduction and adduction) with an abnormal/absent reflex in a newborn.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Causes of neonatal neurological deficits after prolonged labor as background academic context rather than a clinical decision trigger.
Nurses play a critical role in monitoring fetal heart rate and uterine contractions during labor to detect early signs of fetal distress, which can prevent birth asphyxia.
Immediate assessment of a newborn's reflexes, including the Moro reflex, is a key part of the Apgar score and initial neonatal assessment to identify neurological compromise.
What if? If a newborn presents with an asymmetric Moro reflex (only one arm moves), the nurse should suspect a localized physical injury from the delivery, such as a fractured clavicle or a brachial plexus injury (e.g., Erb's palsy), rather than generalized CNS depression from asphyxia.

How to Approach the Question

First, identify the core components of the question: the cause is a 'prolonged delivery,' and the effect is an 'abnormal Moro reflex' in a newborn.
Recognize that a prolonged delivery is an acute, stressful event for the fetus that happens during birth (intrapartum).
Evaluate the options in the context of an acute intrapartum complication.
Birth asphyxia is a direct and acute consequence of complications during labor, such as lack of oxygen.
Maternal hypertension and placental insufficiency are typically chronic, pre-existing conditions that increase risk but are not the immediate event.
Prematurity is a condition related to gestational age, not the duration of labor.

Concept Tested & Keywords

Concept Tested: Causes of neonatal neurological deficits after prolonged labor.
Stem keywords: prolonged delivery, abnormal Moro reflex, newborn
Lead-in keywords: caused by
Clinical cues: The link between a specific intrapartum event (prolonged delivery) and a specific neonatal sign (abnormal Moro reflex).

QFyi0ry7K90llkxFPdDDB3