Gestational age‐related reference values for Apgar score and umbilical cord arterial and venous pH in preterm and term newborns

Abstract

Introduction Despite much literature on reference values of acid‐base status in umbilical cord blood at birth, there are as yet no studies performed to determine gestational age‐dependent references in cord venous blood and no studies on preterm acid‐base standards. Similarly, the normal reference range of Apgar scores for term and preterm infants has not yet been determined. Material and methods Data were obtained from the maternity units of Skåne University Hospital, Malmö and Lund, Sweden, from 2001 to 2010. Validated paired arterial and venous cord pH values were obtained from 27 175 newborns, of whom 18 584 had spontaneous, non‐instrumental vaginal deliveries and a 5‐minute Apgar score equal to or greater than the median value for the individual gestational week. Simple linear and polynomial regression analyses were performed. Values were reported as mean ± standard deviation and median with 2.5th and 97.5th percentiles. Results Median 5‐minute Apgar score was 7 for gestations shorter than 28 weeks, 8 for 28 weeks, 9 for 29‐30 weeks, and 10 from 31 weeks onwards. A linear decline in pH for both cord arterial and venous blood was seen with advancing gestational age (P < 0.001). Conclusions Median 5‐minute Apgar scores were <10 before 31 weeks of gestation. Both umbilical cord arterial and venous pH decreased linearly with increasing gestational age. Further studies are needed to show whether gestational age‐related pH reference ranges might be preferred to fixed cut‐offs in the estimation of umbilical cord acidemia at birth.

Gestational age reference ranges for umbilical cord blood lactate: An external validation study of post‐date pregnancies

“…Based on these concepts, one could also expect umbilical cord blood pH to change with increasing gestational age. In line with this, umbilical cord blood pH has been found to decline with gestational age 16,17 . Kitlinski et al 16 found the mean umbilical artery pH to be 7.26 at 36 gestational weeks and 7.22 at 42 gestational weeks.…”

Intrauterine vertical SARS‐CoV‐2 infection: a case confirming transplacental transmission followed by divergence of the viral genome

“…The neonate in the current case suffered from transient asphyxia attributed to intrauterine hypoxia secondary to placental dysfunction. This was signalled by the pathological CTG result, and validated umbilical cord blood gases revealed a cord arterial and venous pH below normal median reference values for 34 weeks of gestational age 3 . More notably, the neonate had abnormally high cord arterial and venous lactate values, which clearly indicated a hypoxic insult 32 .…”

“…This was signalled by the pathological CTG result, and validated umbilical cord blood gases revealed a cord arterial and venous pH below normal median reference values for 34 weeks of gestational age. 3 More notably, the neonate had abnormally high cord arterial and venous lactate values, which clearly indicated a hypoxic insult. 32 Following initial resuscitation, only standard supportive care of prematurity was needed.…”

“…At 1 minute of age, the neonate had an Apgar score of 1 (heart rate = 1, remaining items = 0), at 5 minutes of age Apgar 4 (heart rate = 2, muscular tonus = 1, reflex irritability = 1, remaining items = 0), and at 10 minutes of age Apgar 8 (heart rate = 2, respiratory activity = 2, skin colour = 1, muscular tonus = 2, reflex irritability = 1). Validated umbilical cord blood gases 3 showed a cord arterial pH of 7.20 and a venous pH of 7.22. Cord arterial lactate was 11 mmol/l and cord venous lactate 10.1 mmol/l.…”

Intrauterine SARS-CoV-2 infection – a case confirming transplacental&nbsp;transmission followed by divergence of the viral genome

“…At one minute of age, the neonate had an Apgar score of 1 (heart rate = 1, remaining items = 0), at ve minutes of age Apgar 4 (heart rate = 2, muscular tonus = 1, re ex irritability = 1, remaining items = 0), and at ten minutes of age Apgar 8 (heart rate = 2, respiratory activity = 2, skin color = 1, muscular tonus = 2, re ex irritability = 1). Validated umbilical cord blood gases 9 from both cord artery and vein were retrieved showing a cord arterial pH of 7.20 and lactate 11 mmol/L (Supplementary table 2). The birth weight was appropriate for gestational age.…”