In this cohort study of neonates born at 35 weeks' gestation or later, those with initially indeterminate POS results that normalized on repeat testing had increased risks of treatable neonatal conditions and hospital care but not of CCHD.
Key Findings
Results
Most asymptomatic newborns had negative early pulse oximetry screening results, while about 2.7% had recovered or positive results.
The cohort included 16 599 newborns born at 35 weeks' gestation or later who underwent early POS at 2 to 6 hours of age.
POS results were negative in 16 160 (97.4%), recovered in 208 (1.3%), and positive in 231 (1.4%).
Setting: a tertiary-level university hospital in Eastern Finland, January 1, 2012, to December 31, 2019.
Mean (SD) gestational age was 39.8 (1.3) weeks and 8349 (50.3%) were female.
Results
Recovered and positive POS results were each associated with markedly higher risk of NICU admission than negative results.
Recovered POS: adjusted risk ratio (ARR) 5.62 (95% CI, 4.58-6.91).
Positive POS: ARR 13.04 (95% CI, 11.77-14.44).
Modified Poisson regression was adjusted for maternal age, parity, BMI, smoking during pregnancy, and newborn sex, gestational age, and birth weight Z score.
Results
Recovered and positive POS results were associated with higher risk of continued hospitalization at 7 days.
Recovered POS: ARR 4.70 (95% CI, 3.07-7.19).
Positive POS: ARR 11.97 (95% CI, 9.26-15.47).
Continued hospitalization at 7 days was a primary outcome along with NICU admission.
Results
Newborns with recovered POS had higher risk of early antibiotic exposure and need for respiratory support than those with negative results.
Antibiotic exposure before 72 hours of life: ARR 5.45 (95% CI, 3.94-7.52).
Need for respiratory support: ARR 10.16 (95% CI, 3.53-29.21).
The wide confidence interval for respiratory support suggests an imprecise estimate.
Results
Respiratory disease, sepsis, and hypoglycemia were more common among newborns with recovered POS than among those with negative POS.
Respiratory disease: 27 (13.0%) vs 214 (1.3%).
Sepsis: 10 (4.8%) vs 127 (0.8%).
Hypoglycemia: 17 (8.2%) vs 565 (3.5%).
Results
No critical congenital heart defect (CCHD) occurred among newborns with recovered POS results.
Recovered POS was defined as an initially indeterminate result that normalized to negative on repeat testing.
The authors conclude recovered results are linked to treatable neonatal conditions and hospital care, but not CCHD.
Conclusions
The authors suggest targeted assessment of newborns with recovered POS may reduce morbidity and prolonged hospitalization, but this requires prospective testing.
Recovered results signal increased risk of treatable neonatal conditions despite normalization.
The study was a retrospective population-based cohort, so it cannot show that targeted assessment improves outcomes.
What This Means
This study looked at more than 16,000 healthy-appearing newborns in Eastern Finland who had a pulse oximetry screening (a painless sensor test of blood oxygen) a few hours after birth. Most babies passed the test. About 1.3% had an initially abnormal reading that returned to normal on repeat testing ("recovered"), and 1.4% had a positive (failed) result.
Babies with recovered results were much more likely than those who passed to be admitted to the neonatal intensive care unit (about 5.6 times as likely) and to still be in hospital at 7 days (about 4.7 times as likely). They also more often received early antibiotics, needed breathing support, and were diagnosed with respiratory disease, infection (sepsis), or low blood sugar. Babies with positive results had even higher risks. None of the babies with recovered results had a critical congenital heart defect.
This research suggests that an initially abnormal oximetry reading that later normalizes may still signal a baby who has a treatable condition and could benefit from closer assessment, even though it does not point to a serious heart defect. The study was observational and conducted in one hospital, so it cannot show that extra monitoring would improve outcomes. The authors call for further prospective studies to test whether targeted assessment could reduce illness and long hospital stays.