Pulse Oximetry Measures a Lower Heart Rate at Birth Compared with Electrocardiography

Objective To examine the effect of time after birth on heart rate (HR) measured by pulse oximetry (PO) (HR PO ) and electrocardiography (ECG) (HR ECG ). Study design HR ECG and HR PO (collected at maximum sensitivity) were assessed in 53 term and preterm infants at birth. ECG electrodes and a PO sensor were attached as soon as possible and HR ECG and HR PO were compared every 30 seconds from 1-10 minutes after birth. Data were compared using a Wilkinson signed-rank test. Clinical relevance (eg, HR  Results Seven hundred fifty-five data pairs were analyzed. Median (IQR) gestational age was 37 (31-39) weeks. Mean (SD) starting time of PO and ECG data collection was 99 (33) vs 82 (26) seconds after birth ( P  = .001). In the first 2 minutes after birth, HR PO was significantly lower compared with HR ECG (94 (67-144) vs 150 (91-153) bpm at 60 seconds ( P P P P = .05), 56% vs 26% at 90 seconds ( P P Conclusions In infants at birth, HR PO is significantly lower compared with ECG with clinically important differences in the first minutes.