Objective To assess whether defined reference ranges of oxygen saturation (SpO₂) and heart rate (HR) of term infants after birth also apply for infants born after midwifery supervised uncomplicated vaginal birth, where delayed cord clamping (DCC) and immediate skin to skin contact (ISSC) is routine management.

Design Prospective observational study.

Setting and patients Infants born vaginally after uncomplicated birth, that is, no augmentation, maternal pain relief or instrumental delivery.

Interventions Midwives supervising uncomplicated birth at home or in hospital in the Leiden region (The Netherlands) used an oximeter and recorded SpO₂ and HR in the first 10 min after birth.

Main outcome measures SpO₂ and HR values were compared to the international defined reference ranges.

Results In Leiden, values of 109 infants were obtained and are comparable with previously defined reference ranges, except for a higher SpO_{2 (}p<0.05) combined with a slower increase in the first 3 min. The Leiden cohort also had a lower HR (p<0.05) during the first 10 min with a slower increase in the first 3 min. In the first minutes after birth, tachycardia (HR>180 bpm) occurred less often, and a bradycardia (<80 bpm) more often (p<0.05).

Conclusions Defined reference ranges can be used in infants born after uncomplicated vaginal birth with DCC and ISSC, but higher SpO₂ and lower HR were observed in the first minutes.