Gestational age‐related reference values for Apgar score and umbilical cord arterial and venous pH in preterm and term newborns
Open accessAbstract
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.
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In another study (N=18,584), the 2.5th percentile values at 37, 40, and 42 weeks' gestation were 7.11, 7.10, and 7.09, respectively.
“In another study (N¼18,584), we found that the 2.5th percentile values (which is close to but not identical to mean À2 SD) at 37, 40, and 42 weeks' gestation were 7.11, 7.10, and 7.09, respectively.58”
From Umbilical cord pH, blood gases, and lactate at birth: normal values, interpretation, and clinical utility. (2023) · cites this paper as [58]
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- Authors
- Zaigham, M., Källén, K., & Olofsson, P.
- Affiliations
- Lund University (SE)
- Corresponding author
- Zaigham, Mehreen
- Venue
- Acta Obstetricia Et Gynecologica Scandinavica
- Publisher
- Wiley
- Published
- 2019-08-12
- Volume
- 98
- Issue
- 12
- Pages
- 1618-1623
- ISSN
- 0001-6349 (ISSN-L)
- 1600-0412
- OpenAlex
- W2960013749
- Cited by
- 31
- References
- 30
- Citations by year
- 2026: 8 · 2025: 4 · 2024: 3 · 2023: 10 · 2022: 4 · 2021: 1 · 2020: 1
- FWCI
- 1.11
- Type
- journal article
- Language
- en
- Open access
- hybrid
- doi.org
- Licence
- Locations
- Acta Obstetricia Et Gynecologica Scandinavica (publishedVersion, cc-by-nc)
- PubMed (publishedVersion)
- Lund University Publications (Lund University) (submittedVersion)
- Funders
- Region Skåne
- Topics
- Health Sciences › Medicine › Pulmonary and Respiratory Medicine › Neonatal Respiratory Health Research
- Health Sciences › Medicine › Pediatrics, Perinatology and Child Health › Infant Development and Preterm Care
- Health Sciences › Health Professions › General Health Professions › Maternal and Neonatal Healthcare
- Keywords
- Apgar score, umbilical cord pH, gestational age, reference values, preterm infants, term infants, acid-base status
- MeSH terms
- Apgar Score, Arteries, Fetal Blood, Gestational Age, Humans, Hydrogen-Ion Concentration, Infant, Newborn, Reference Values, Veins, Premature Birth, Term Birth
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