Department of Obstetrics and Gynecology, The University of North Carolina at Chapel Hill, Chapel Hill, NC.
Department of Women's Health, Dell Medical School, The University of Texas at Austin, Austin, TX.
Am J Obstet Gynecol. 2023 Oct;229(4):439.e1-439.e11. doi: 10.1016/j.ajog.2023.03.031. Epub 2023 Mar 25.
Metabolic acidemia is a known risk factor for serious adverse neonatal outcomes in both preterm and term infants.
This study aimed to evaluate the clinical significance of delivery umbilical cord gas measurements with regard to serious adverse neonatal outcomes, and to determine if distinct thresholds for defining metabolic acidemia differ in their ability to predict such adverse neonatal complications.
This is a retrospective cohort study of singleton live-born deliveries between January 2011 and December 2019. Stratification according to gestational age at birth (≥35 and <35 weeks of gestation) was performed, and comparisons of maternal characteristics, obstetrical complications, intrapartum events, and adverse neonatal outcomes were made between neonates with metabolic acidemia and those without. Metabolic acidemia (based on delivery umbilical cord gas analyses) was defined using both American College of Obstetricians and Gynecologists and Eunice Kennedy Shriver National Institute of Child Health and Human Development criteria. The primary outcome of interest was hypoxic-ischemic encephalopathy requiring whole-body hypothermia.
A total of 91,694 neonates born at ≥35 weeks of gestation met the inclusion criteria. By American College of Obstetricians and Gynecologists criteria, 2659 (2.9%) infants had metabolic acidemia. Neonates with metabolic acidemia were at markedly increased risk for neonatal intensive care unit admission, seizures, need for respiratory support, sepsis, and neonatal death. Metabolic acidemia by American College of Obstetricians and Gynecologists criteria was associated with an almost 100-fold increased risk of hypoxic-ischemic encephalopathy requiring whole-body hypothermia (relative risk, 92.69; 95% confidence interval, 64.42-133.35) in neonates born at ≥35 weeks of gestation. Diabetes mellitus, hypertensive disorders of pregnancy, postterm deliveries, prolonged second stages, chorioamnionitis, operative vaginal deliveries, placental abruption and cesarean deliveries were associated with metabolic acidemia in neonates born ≥ 35 weeks of gestation. The highest relative risk was in those diagnosed with placental abruption (relative risk, 9.07; 95% confidence interval, 7.25-11.36). The neonatal cohort born <35 weeks of gestation had similar findings. When comparing those infants born ≥ 35 weeks of gestation with metabolic acidemia by American College of Obstetricians and Gynecologists criteria vs Eunice Kennedy Shriver National Institute of Child Health and Human Development criteria, the Eunice Kennedy Shriver National Institute of Child Health and Human Development criteria identified more neonates at risk for serious adverse neonatal outcomes. In particular, 4.9% more neonates were diagnosed with metabolic acidemia, and 16 more term neonates were identified as requiring whole-body hypothermia. Mean 1-minute and 5-minute Apgar scores were similar and reassuring among neonates born at ≥35 weeks of gestation with and without metabolic acidemia as defined by both American College of Obstetricians and Gynecologists and Eunice Kennedy Shriver National Institute of Child Health and Human Development criteria (8 vs 8 and 9 vs 9, respectively; P<.001). Sensitivity and specificity were 86.7% and 92.2%, respectively, with the Eunice Kennedy Shriver National Institute of Child Health and Human Development criteria, and 74.2% and 97.2% with the American College of Obstetricians and Gynecologists criteria.
Infants with metabolic acidemia identified on cord gas collection at delivery are at considerably greater risk of serious adverse neonatal outcomes, including an almost 100-fold increased risk of hypoxic-ischemic encephalopathy requiring whole-body hypothermia. Use of the more sensitive Eunice Kennedy Shriver National Institute of Child Health and Human Development criteria for defining metabolic acidemia identifies more neonates born at ≥35 weeks of gestation at risk for adverse neonatal outcomes, including hypoxic-ischemic encephalopathy requiring whole-body hypothermia.
代谢性酸中毒是早产儿和足月儿严重不良新生儿结局的已知危险因素。
本研究旨在评估分娩脐带血气测量值与严重不良新生儿结局的临床意义，并确定代谢性酸中毒的定义是否存在不同的阈值，以预测此类不良新生儿并发症。
这是一项回顾性队列研究，纳入了 2011 年 1 月至 2019 年 12 月期间的单胎活产分娩。根据出生时的胎龄进行分层（≥35 周和<35 周），比较代谢性酸中毒新生儿和非代谢性酸中毒新生儿的产妇特征、产科并发症、产时事件和不良新生儿结局。代谢性酸中毒（基于分娩脐带血气分析）采用美国妇产科医师学会和 Eunice Kennedy Shriver 国立儿童健康与人类发展研究所的标准进行定义。主要研究结果为需要全身低温治疗的缺氧缺血性脑病。
共有 91694 名胎龄≥35 周的新生儿符合纳入标准。根据美国妇产科医师学会的标准，2659 名（2.9%）婴儿患有代谢性酸中毒。患有代谢性酸中毒的新生儿有明显更高的入住新生儿重症监护病房、癫痫发作、需要呼吸支持、败血症和新生儿死亡的风险。胎龄≥35 周的新生儿中，根据美国妇产科医师学会的标准，代谢性酸中毒与需要全身低温治疗的缺氧缺血性脑病的风险几乎增加了 100 倍（相对风险，92.69；95%置信区间，64.42-133.35）。胎龄≥35 周的新生儿中，糖尿病、妊娠高血压疾病、过期产、第二产程延长、绒毛膜羊膜炎、阴道助产、胎盘早剥和剖宫产与代谢性酸中毒有关。诊断为胎盘早剥的相对风险最高（相对风险，9.07；95%置信区间，7.25-11.36）。胎龄<35 周的新生儿队列也有类似的发现。当比较胎龄≥35 周的新生儿中美国妇产科医师学会标准和 Eunice Kennedy Shriver 国立儿童健康与人类发展研究所标准的代谢性酸中毒时，Eunice Kennedy Shriver 国立儿童健康与人类发展研究所的标准识别出更多有严重不良新生儿结局风险的婴儿。特别是，根据美国妇产科医师学会和 Eunice Kennedy Shriver 国立儿童健康与人类发展研究所的标准，更多的新生儿被诊断为代谢性酸中毒，需要全身低温治疗的足月新生儿增加了 16 例。胎龄≥35 周的新生儿中，根据美国妇产科医师学会和 Eunice Kennedy Shriver 国立儿童健康与人类发展研究所的标准，1 分钟和 5 分钟的平均 Apgar 评分相似且令人安心（分别为 8 分对 8 分和 9 分对 9 分；P<.001）。Eunice Kennedy Shriver 国立儿童健康与人类发展研究所标准的敏感性和特异性分别为 86.7%和 92.2%，美国妇产科医师学会标准的敏感性和特异性分别为 74.2%和 97.2%。
分娩时脐带血气采集发现代谢性酸中毒的婴儿发生严重不良新生儿结局的风险显著增加，包括需要全身低温治疗的缺氧缺血性脑病的风险增加近 100 倍。使用更敏感的 Eunice Kennedy Shriver 国立儿童健康与人类发展研究所标准来定义代谢性酸中毒，可以识别出更多胎龄≥35 周的新生儿存在不良新生儿结局的风险，包括需要全身低温治疗的缺氧缺血性脑病。
