Acute cardiac care & resuscitationCohort study
The relationship between umbilical arterial pH, newborn heart rate and ventilation at birth – a prospective observational study
- prospective cohort study
Authors' conclusion
There was no linear correlation between UA-pH and HR at one minute. Although HR alone was not a good indicator of acidaemia, low UA-pH is associated with bradycardia and PPV. Apgar scores reflected the degree of birth asphyxia very well.
Study context
- Population
- Newborns of gestational age ≥28 weeks at Stavanger University Hospital, Norway, June 2019-November 2021
- Participants
- 3,662 newborns
- Exposure
- Umbilical arterial pH (UA-pH) categories <7.00, 7.00-7.09, 7.10-7.19 vs reference group 7.20-7.50; outcome measures newborn HR and PPV
- UA-pH <7.00n = 20 (0.5%)
- UA-pH 7.00-7.09n = 140 (3.8%)
- UA-pH 7.10-7.19n = 833 (23%)
- UA-pH 7.20-7.50n = 2,669 (73%)reference
Main finding
As reported in the abstract
UA-pH · at birth
median (quartiles) UA-pH
7.24 (7.19, 7.29)
Observational data: associations, not effects.
Further findings
| Outcome | UA-pH <7.00 | UA-pH 7.00-7.09 | UA-pH 7.10-7.19 | UA-pH 7.20-7.50 | OR (CI) | P value | |
|---|---|---|---|---|---|---|---|
| Bradycardia (HR <100 bpm in the first minute) | 50% | Not reported in the abstract | Not reported in the abstract | Not reported in the abstract | 5.0 (1.9–12.9) | P < 0.001 | |
| PPV at birth | One-third | Not reported in the abstract | Not reported in the abstract | Not reported in the abstract | 21.9 (8.0–55.4) | P < 0.001 | |
| 0.050.21520Odds ratio (log scale) |
- PPV at birth — PPV provided to all newborns
- 117/3662 (3.2%)
Linear correlation between UA-pH and first measured HR · 16 (11, 30) s
- r
- 0.07
- p
- P < 0.001
- weak and clinically insignificant
Linear correlation between UA-pH and HR · one minute
- r
- −0.03
- p
- P = 0.07
- no linear correlation
Apgar scores
- Apgar scores were strongly associated with UA-pH
Original publication
The relationship between umbilical arterial pH, newborn heart rate and ventilation at birth – a prospective observational study. Resuscitation. Published 7 July 2026. doi:10.1016/j.resuscitation.2026.111197
Summarised from the published abstract; every number is checked against it