Background Umbilical cord blood gas analysis is recommended to be taken when there has been concern about the baby in labour or immediately following birth and cord arterial lactate (CAL) has become a standard measurement on blood gas reports. However, evidence regarding thresholds for concern or appropriate management remains limited. Within our unit, guidance on further management of infants following detection of potentially ‘raised’ CAL was ratified based on available literature.

Objectives This study reports on the clinical correlates of a raised cord arterial lactate following introduction of a guidance to manage newborns with raised CAL.

Methods A single-centre retrospective review of all term neonates (>35 weeks gestational age) with a recorded CAL over a 6-month period (July 2018 to December 2018). Babies were identified from maternity monthly statistics and data extracted from electronic medical records. Clinical course and adverse events were evaluated between risk groups: Low-risk CAL ≤5 mmol/L, moderate-risk CAL 5–10 mmol/L and high-risk CAL ≥10 mmol/L. Adverse events include therapeutic hypothermia, mechanical ventilation, neonatal death and usage of non-invasive ventilation.

Results Among 2591 infants born ≥35 weeks gestation, 658 (25%) had a recorded CAL (44% had a CAL <5 mmol/L, 49% had CAL 5–10 mmol/L and 7% had CAL ≥10 mmol/L). Gender gestation and birth weight were in equal proportions in all 3 groups. The high-risk group with CAL ≥10 mmol/L required more resuscitation at birth, NICU admission and had more adverse events compared to groups with CAL ≤10 mmol/L. There was no difference in these events in infants where CAL <5 mmol/L compared to those with a CAL 5–10 mmol/L.

A repeat blood lactate level was taken in 48% and 98% of CAL 5–10 mmol/L and CAL ≥10 mmol/L groups respectively. The time range for first repeat varied widely and babies who had increased lactate level after repeat did not receive more treatment than those where the lactate fell. Routine repeat of blood lactate levels in clinically well babies with CAL 5–10 mmol/L did not appear to change management.

Conclusions A large number of babies are currently labelled as moderate to high risk based on a single raised CAL which may lead to unnecessary medical interventions. Better evidence is needed to determine the significance of a raised CAL, define clinically important thresholds for concern and optimal interventional strategies.