PROVING CAUSATION IN HYPOXIC ISCHEMIC ENCEPHALOPATHY/CEREBRAL PALSY ANOXIC BIRTH INJURY CASES

January 13th, 2026

Part Two: Abnormal Apgar Scores are not Always Present when a Fetus has Suffered Hypoxic or Anoxic Birth Injury

By David A. Bowling and Lauren P. Jones

A Multipart Series from the Bowling Law Firm, APLC

I.      Introduction

In our first installment of this series, we presented an overview of the criteria for establishing a hypoxic or anoxic birth injury as published by the American College of Obstetrics and Gynecology (“ACOG”). We emphasized that to establish that a child’s cerebral palsy or other neurologic disorder was a product of the birthing process, attorneys must be prepared to address the criteria published by ACOG for establishing that the infant suffered an injurious hypoxic ischemic encephalopathy (HIE).

In ACOG’s view, a multidimensional assessment of neonatal status and potential contributing factors is utilized. The factors to be considered in assessing for an intrapartum cause of the neurological deficits include: the mother’s medical history and obstetric background, intrapartum factors like fetal heart rate and delivery complications, and placental pathology. These factors guide providers in determining whether a hypoxic ischemic event during the labor and/or delivery timeframe contributed to neonatal encephalopathy.

Neonatal encephalopathy, which is defined as the disturbed neurologic function in an infant’s earliest days of life,[1] often reveals itself as a subnormal level of consciousness or seizures. Additionally, the infant may display signs of respiratory distress. There may also be a lack of muscle tone and reflexes.

Neonatal encephalopathy due to acute hypoxia ischemia will usually be accompanied by abnormal neonatal signs and other red-flag events that were observed around the time of labor and delivery. Assessments using the below criteria aim to collect a variety of markers to determine if the clinical picture is consistent with acute hypoxia ischemia or if the infant’s condition could be explained by other etiologies.

The criteria used by providers in assessing hypoxic ischemic encephalopathy are as follows:

1. Apgar score of less than 5 at 5 minutes and 10 minutes
2. Fetal umbilical artery acidemia
3. Neuroimaging evidence of acute brain injury seen on brain MRI or magnetic resonance spectroscopy consistent with hypoxia ischemia
4. Presence of multisystem organ failure consistent with hypoxic ischemic encephalopathy

(American College of Obstetricians and Gynecologists. Executive Summary: Neonatal Encephalopathy and Neurologic Outcome. Second Edition. Obstet Gynecol. 2014; 123:896-901).

As attorneys concentrating in the representation of families or children who have suffered from cerebral palsy and/or hypoxic ischemic encephalopathy, we have seen many cases in which most or all the criteria are met, and yet the child was born with relatively normal Apgar scores. These normal Apgars will be urged by the defense to constitute proof that something other than inadequate oxygenation during the birthing process is responsible for the injury. But as will be seen, there is a scientific basis for establishing that the presence of hypoxic ischemic encephalopathy and/or cerebral palsy is not incompatible with relatively normal Apgar scores.

II.    ACOG’s Position on Apgar Scores

The Apgar score is a quick way for health professionals to evaluate the health of all newborns at one and five minutes after birth and in response to resuscitation. It was originally developed in 1952 by an anesthesiologist at Columbia University, Virginia Apgar, to address the need for a standardized way to evaluate infants shortly after birth.

Today, the categories developed by Apgar to assess the health of a newborn remain largely the same as in 1952, though the way they are implemented and used has evolved over the years. The score is determined through the evaluation of the newborn in five criteria: activity (tone), pulse, grimace, appearance, and respiration. For each criterion, newborns can receive a score from 0 to 2. The inference is scored at one- and five-minute intervals. If abnormal, the score is repeated at 10 minutes.

As stated above, the Apgar score is simply a quick way of determining whether the infant needs immediate resuscitation or other care. It is almost invariably scored by nursery unit nurses.

In ACOG’s first major work on establishing criteria for connecting the birthing process to neurologic injury, it emphasized that low Apgar scores, defined as 0-3 at five minutes, can be suggestive of a birth injury but can be also explained by other causes. ACOG’s position was that a low Apgar score does not necessarily mean that the infant has suffered from birth hypoxia as stated in Neonatal Encephalopathy and Cerebral Palsy: Defining the Pathogenesis and Pathophysiology:[2]

 A 5-minute Apgar score of 7-10 is considered “normal.” Scores of 4, 5, and 6 are intermediate and are not markers of high levels of risk of later neurologic dysfunction. A low Apgar score (<4) is a nonspecific indicator of illness in the neonate and often is the first recognizable marker of encephalopathy. However, a low 1- or 5-minute score alone does not demonstrate that later development of cerebral palsy was caused by perinatal asphyxia, and it is well established that the 1- or 5-minute Apgar score is a poor predictor of long-term neurologic outcome in the individual patient (5). Even a 5-minute score of 0-3, although possibly a result of hypoxia, is limited as an indicator of the severity of the problem and correlates poorly with future neurologic outcome (5, 6).

In the second edition, ACOG characterized an Apgar score of less than five in five minutes and 10 minutes as a “neonatal sign consistent with an acute peripartum or intrapartum event.” But it said this:

1. Low Apgar scores at 5 minutes and 10 minutes clearly confer an increased relative risk of cerebral palsy. The degree of Apgar abnormality at 5 minutes and 10 minutes correlates with the risk of cerebral palsy. However, most infants with low Apgar scores will not develop cerebral palsy.
2. There are many potential causes for low Apgar scores. If the Apgar score at 5 minutes is greater than or equal to 7, it is unlikely that peripartum hypoxia-ischemia played a major role in causing neonatal encephalopathy.

(ACOG Second Edition, page E1484).

To take a cynical view, ACOG is saying that a low Apgar score is not very good evidence of birth hypoxia as a cause for neonatal depression, but a high Apgar score is evidence that no hypoxic birth injury occurred. In other words, the Apgar score is only valuable in assessing the causation issue if it is a high score and therefore helpful to the obstetrician and/or the hospital nursing staff in defending a birth injury case. As stated above, there is a scientific basis[3] for establishing that the cause of a patient’s neurologic devastation is due to failures to maintain a well oxygenated fetus during the birthing process.

III.    The Medical Literature’s  Position on Apgar Scores

Much of the published medical literature agrees that “a normal Apgar score does not definitively rule out HIE and should not be relied upon to establish a newborn as healthy.”[4] It is incumbent upon physicians to recognize that Apgar scores are limited – a screening tool designed to assess if a newborn is physiologically stable.

Apgar scores are influenced by gestational age, maturity, drugs, and other factors. And Apgar scores assigned during resuscitation and intubation efforts cannot provide specific information about an infant’s broader clinical condition. These limitations prompted researchers to come up with alternatives to the conventional Apgar score. The Specified-Apgar and Expanded-Apgar scores were developed to allow for the assessment of a newborn’s condition independent of interventions and gestational age. An even further improved and comprehensive scoring system was then developed to aid in predicting adverse neonatal outcomes – the Combined Apgar score.[5]

Clinical studies comparing the different versions of the Apgar score found that the conventional test had a low sensitivity of 81% for birth asphyxia. The American collaborative perinatal project of 1959-66 also confirmed the conventional Apgar test’s poor sensitivity:[6] only 27% of children who later developed cerebral palsy scored below 7 at 5 minutes. Per the medical literature, “given that up to 20% of birth asphyxia cases may be missed on Apgar screening, practitioners providing follow-up care must consider HIE even in infants whose Apgar scores were normal.” The Combined-Apgar score has shown superiority to the conventional Apgar score in birth asphyxia diagnoses, with a higher sensitivity in birth asphyxia cases observed.[7]

Because the newer versions of the Apgar score have been found to be the most reliable, more providers are advocating for the phasing out of the conventional Apgar test and the universal adoption of the more advanced Apgar versions.

IV.    Conclusion

Apgar scores are a useful tool for quickly assessing whether a newborn needs resuscitation or other immediate medical attention. And Apgar scores have at least some place in the assessment of whether neonatal encephalopathy in a particular case was due to a lack of oxygen during the birthing process. But the scientific evidence shows that there can be significant hypoxic ischemic encephalopathy which causes anoxic brain injury that simply is not revealed by the Apgar score. Accordingly, practitioners handling medical malpractice birth injury cases need to be prepared to challenge defense theories that a relatively normal Apgar score can “rule out” brain injury from hypoxia in the birthing process.

[1] This definition applies when the infant is born at 35 weeks or older.

[2] The American College of Obstetricians and Gynecologists. Neonatal Encephalopathy and Cerebral Palsy: Defining the Pathogenesis and Pathophysiology. 2003.

[3] In almost every malpractice case, and invariably in birth injury malpractice cases, expert testimony must be offered to establish causation between the errors committed by the obstetrician and/or obstetrical nurses during the labor and delivery of the infant and the neurological injury. Expert testimony must follow the methods of science to be admissible into evidence under the Daubert evidentiary standards which have emerged from the United States Supreme Court’s interpretation of Rule 702 of the Federal Rules of Civil Procedure. The Daubert standards have essentially been adopted by every jurisdiction in the United States.

[4] Sheikh, T. Late Diagnosis of Hypoxic-Ischemic Encephalopathy in a Child with Normal Apgar Scores. J Pediatr Neurol Med. 2017.

[5] Dalili, H. Comparison of the Four Proposed Apgar Scoring Systems in the Assessment of Birth Asphyxia and Adverse Early Neurologic Outcomes. PLOS ONE. 2015.

[6] Ruth, V. Perinatal brain damage: predictive value of metabolic acidosis and the Apgar score. BMJ. 1988.

[7] Njie, A. A comparative analysis of APGAR score and the gold standard in the diagnosis of birth asphyxia at a tertiary health facility in Kenya. PLOS ONE. 2023.