The Finnegan Neonatal Abstinence Scoring System (FNASS) is a standardized tool used by healthcare professionals to assess the severity of drug withdrawal symptoms in newborns, a condition known as Neonatal Abstinence Syndrome (NAS). Developed in 1975, this system provides an objective, numerical measure of an infant’s withdrawal signs, which is a necessary step for guiding clinical care. The FNASS is the most widely validated and commonly utilized scoring system for quantifying the severity of neonatal withdrawal signs in hospital settings. Its purpose is to ensure consistent monitoring and to help determine when an infant requires pharmacological intervention to manage their withdrawal symptoms effectively.
Understanding Neonatal Abstinence Syndrome
Neonatal Abstinence Syndrome (NAS) is a condition newborns experience when they withdraw from substances, most commonly opioids, they were exposed to in the womb. During pregnancy, drugs ingested by the mother pass through the placenta and into the fetal bloodstream, causing the baby to develop a physical dependence. After birth, the infant’s continuous supply of the substance is abruptly halted, which causes their central nervous system (CNS) to become overstimulated as the drug slowly clears from their system.
The infant’s body attempts to adjust to the sudden absence of the substance, leading to a state of hyperexcitability. This withdrawal process primarily affects three major areas: the central nervous system, the gastrointestinal system, and the autonomic nervous system. Symptoms can be triggered by exposure to various substances, including prescription and illicit opioids, as well as non-opioids like selective serotonin reuptake inhibitors (SSRIs), benzodiazepines, and alcohol.
The onset and severity of NAS symptoms depend on several factors, including the type of drug used, the last time the mother used the substance, and the infant’s own metabolism. For instance, withdrawal from heroin or other short-acting opioids typically begins within the first 48 to 72 hours, while longer-acting opioids like methadone or buprenorphine may cause symptoms to appear later, often up to 5 to 7 days after birth.
The Components of the Finnegan Scoring System
The Finnegan Scoring System assesses 21 specific signs of withdrawal to produce a cumulative score. These 21 signs are organized into three distinct categories based on the physiological system they affect: Central Nervous System (CNS) disturbances, Metabolic/Vasomotor/Respiratory disturbances, and Gastrointestinal (GI) disturbances. Each symptom is assigned a point value from one to five, with higher scores reflecting greater severity and clinical significance.
The Central Nervous System disturbance category includes signs of hyperirritability and sensory overstimulation. Examples include tremors, which are scored differently based on whether they occur when the infant is disturbed or undisturbed, and the degree of increased muscle tone. Other CNS items include excessive, high-pitched crying and an exaggerated Moro reflex (the infant’s startle response). Convulsions, which represent the most severe CNS manifestation, are assigned the highest point value within this category.
The Metabolic, Vasomotor, and Respiratory disturbance section tracks signs related to the body’s autonomic instability. This includes sweating, fever, and blotchy skin coloring, known as mottling. Respiratory signs like rapid breathing (a rate greater than 60 breaths per minute) are scored, with an even higher score given if retractions (the pulling in of the chest wall with breathing) are also present. Frequent yawning and sneezing are also quantified as signs of withdrawal.
The Gastrointestinal disturbances category focuses on the infant’s feeding and digestive difficulties. Symptoms tracked here include excessive, uncoordinated sucking and poor feeding. Digestive issues such as regurgitation, vomiting, and loose or watery stools are also scored, as these can lead to dehydration and poor weight gain.
Interpreting Scores and Guiding Treatment Decisions
The calculated Finnegan score guides clinical management, helping the care team decide on the appropriate level of intervention. For all infants at risk for NAS, the first line of defense is supportive, non-pharmacological care, which includes:
- Gentle rocking.
- Swaddling.
- Skin-to-skin contact.
- Minimizing environmental stimuli like bright lights and loud noises.
Pharmacological treatment is typically initiated when the infant’s withdrawal symptoms become severe enough to interfere with their ability to feed, sleep, and be consoled. The commonly accepted thresholds for starting medication are based on consistent elevation of the score over time, not just a single high score. Intervention is generally triggered if the infant maintains three consecutive scores of 8 or higher, or if the infant records two consecutive scores of 12 or higher, despite receiving optimal supportive care. Scoring is done frequently, often every three to four hours, and may be increased to every two hours if scores are high, to closely track symptom progression.
When medication is mandated, the goal is to provide a substitute opioid to slowly wean the infant off dependence. For opioid-related NAS, morphine is considered the first-line therapy, though methadone and buprenorphine are also used. If the primary opioid does not adequately control the symptoms, a second agent like phenobarbital or clonidine may be added to manage severe CNS symptoms, such as seizures or extreme irritability.
The Finnegan score is continuously used to monitor the effectiveness of the medication. Once scores remain consistently below the treatment threshold (e.g., less than 8 for 48 hours or more), the medical team gradually decreases the medication dose in a process called weaning. This slow reduction helps the infant adjust without experiencing another surge of severe withdrawal symptoms. Scoring continues after medication is stopped to ensure the infant is stable before discharge.