Effect of later cord clamping on umbilical cord blood gas in term neonates of diabetic mothers: a randomized clinical trial

OBJECTIVE: To evaluate the effect of later cord clamping (LCC) on umbilical arterial blood gas in neonates of diabetic mothers. METHODS: This prospective study included a group of 160 diabetic mothers (DM) whose neonates were randomized to immediate cord clamping (ICC) (≤ 15 s after birth) or LCC (≥ 30 s after birth), and a group of 208 non-diabetic mothers (NDM) whose neonates were randomized to ICC or LCC as a reference. Cord arterial pH, base excess (BE), bicarbonate (HCO(3)(−)), partial pressure of carbon dioxide (pCO(2)), partial pressure of oxygen (pO(2)), lactate, hemoglobin, hematocrit and glucose were compared among groups. RESULTS: In neonates of DM, there was no significant difference in cord arterial pH between the ICC and LCC group. LCC of ≥ 30 s decreased umbilical arterial HCO(3)(−) and BE and increased lactate (ICC versus LCC, HCO(3)(−): 24.3 (22.7, 25.8) versus 23.7 (22.3, 24.7) mmol/L, P = 0.01; BE: -2.70 (-4.80, -1.50) versus − 3.72 (-5.66, -2.36) mmol/L, P = 0.006; lactate: 2.1 (1.6, 3.7) versus 2.7 (2.1, 4.3) mmol/L, P = 0.005), without the alterations of pCO(2), pO(2), hemoglobin, hematocrit and glucose. Similar results were found in neonates of NDM (ICC versus LCC, HCO(3)(−): 24.3 (23.1, 25.7) versus 23.5 (22.3, 24.8) mmol/L, P = 0.01; BE: -2.39 (-3.73, -1.51) versus − 3.40 (-4.73, -1.91) mmol/L, P = 0.001; lactate: 2.2 (1.9, 3.3) versus 2.5 (2.0, 4.3) mmol/L, P = 0.01), except for the higher level of hemoglobin in the LCC group. The majority of diabetic mothers (ICC: 92.0%; LCC: 91.8%) had good blood glucose control. No differences were observed in acid-base status and glucose between neonates of DM and neonates of NDM in both ICC and LCC, but hemoglobin and hematocrit were elevated after ICC in neonates of DM compared to neonates of NDM. CONCLUSIONS: Later cord clamping of ≥ 30 s resulted in a tendency towards metabolic acidosis of umbilical arterial blood in neonates of DM and NDM. Umbilical arterial blood gas parameters at birth were similar in neonates of DM and NDM. TRIAL REGISTRATION: ClinicalTrials.gov: NCT04369313; date of registration: 30/04/2020 (retrospectively registered).