延迟组术前的平均血红蛋白水平为12.0 g/L，即刻组为11.6 g/L。延迟组术后第一天平均血红蛋白水平为10.1 g/L，即刻组为9.8 g/L，与术前相比差异均不显著。延迟组新生儿的平均血红蛋白水平为18.1 g/L，显著高于即刻组（16.4 g/L）。两组中各有1例非计划子宫切除。
Title: Effect of Delayed vs Immediate Umbilical Cord Clamping on Maternal Blood Loss in Term Cesarean Delivery: A Randomized Clinical Trial
Author: Stephanie E. Purisch, Cande V. Ananth, Brittany Arditi, Logan Mauney, Barouyr Ajemian, Amy Heiderich, Tina Leone, Cynthia Gyamfi-Bannerman
Importance The American College of Obstetricians and Gynecologists recommends a delay in umbilical cord clamping in term neonates for at least 30 to 60 seconds after birth. Most literature supporting this practice is from low-risk vaginal deliveries. There are no published data specific to cesarean delivery.
Objective To compare maternal blood loss with immediate cord clamping vs delayed cord clamping in scheduled cesarean deliveries at term (≥37 weeks).
Design, Setting, and Participants Randomized clinical trial performed at 2 hospitals within a tertiary academic medical center in New York City from October 2017 to February 2018 (follow-up completed March 15, 2018). A total of 113 women undergoing scheduled cesarean delivery of term singleton gestations were included.
Interventions In the immediate cord clamping group (n = 56), cord clamping was within 15 seconds after birth. In the delayed cord clamping group (n = 57), cord clamping was at 60 seconds after birth.
Main Outcomes and Measures The primary outcome was change in maternal hemoglobin level from preoperative to postoperative day 1, which was used as a proxy for maternal blood loss. Secondary outcomes included neonatal hemoglobin level at 24 to 72 hours of life.
Results All of the 113 women who were randomized (mean [SD] age, 32.6 [5.2] years) completed the trial. The mean preoperative hemoglobin level was 12.0 g/dL in the delayed and 11.6 g/dL in the immediate cord clamping group. The mean postoperative day 1 hemoglobin level was 10.1 g/dL in the delayed group and 9.8 g/dL in the immediate group. There was no significant difference in the primary outcome, with a mean hemoglobin change of −1.90 g/dL (95% CI, −2.14 to −1.66) and −1.78 g/dL (95% CI, −2.03 to −1.54) in the delayed and immediate cord clamping groups, respectively (mean difference, 0.12 g/dL [95% CI, −0.22 to 0.46]; P = .49). Of 19 prespecified secondary outcomes analyzed, 15 showed no significant difference. The mean neonatal hemoglobin level, available for 90 neonates (79.6%), was significantly higher with delayed (18.1 g/dL [95% CI, 17.4 to 18.8]) compared with immediate (16.4 g/dL [95% CI, 15.9 to 17.0]) cord clamping (mean difference, 1.67 g/dL [95% CI, 0.75 to 2.59]; P < .001). There was 1 unplanned hysterectomy in each group.
Conclusions and Relevance Among women undergoing scheduled cesarean delivery of term singleton pregnancies, delayed umbilical cord clamping, compared with immediate cord clamping, resulted in no significant difference in the change in maternal hemoglobin level at postoperative day 1.