Holzmann Malin, Wretler Stina, Cnattingius Sven, Nordström Lennart
J Perinat Med. 2015 Jul;43(4):473-9. doi: 10.1515/jpm-2014-0105.
To identify cardiotocography (CTG) patterns associated with increased risk of intrapartum fetal acidemia.
A prospective observational cohort study of 1070 women with fetal scalp blood sampling (FBS) during labor was conducted at Karolinska University Hospital, Stockholm, Sweden. Women with a nonreassuring CTG pattern underwent FBS, and lactate concentration was measured at the bedside. Lactate concentrations >4.8 mmol/L were defined as fetal acidemia. A senior obstetrician, blinded to the lactate concentration at FBS, visually interpreted the CTG tracings that had prompted FBS.
There were 2134 FBSs performed on 1070 laboring women, constituting 11% of all deliveries at this labor ward. The CTG patterns with the highest frequency of lactacidemia at FBS were late or severe variable decelerations combined with tachycardia (20%-25% at first FBS and 33%-49% at last FBS). With a normal baseline fetal heart rate, normal variability, and absence of serious decelerations, the fetal scalp blood lactate concentration at the first FBS was normal in 97.5% of cases. The group with isolated reduced variability had no increased prevalence of acidemia and median lactate concentration did not differ from the normal group.
Isolated reduced variability is in most cases not a sign of hypoxia. If development of hypoxia is ruled out with one FBS, this pattern does not require monitoring with repetitive FBSs throughout labor. Late decelerations and severe variable decelerations increase the risk for intrapartum fetal metabolic acidemia to the same extent. The combination of these decelerations and tachycardia was associated with the highest rate of fetal metabolic acidemia.
确定与产时胎儿酸血症风险增加相关的胎心监护（CTG）模式。
在瑞典斯德哥尔摩的卡罗林斯卡大学医院，对1070名分娩时进行胎儿头皮血采样（FBS）的女性进行了一项前瞻性观察队列研究。CTG模式异常的女性接受FBS检查，并在床边测量乳酸浓度。乳酸浓度>4.8 mmol/L被定义为胎儿酸血症。一位资深产科医生在不知道FBS时乳酸浓度的情况下，对引发FBS的CTG描记图进行视觉解读。
对1070名分娩女性进行了2134次FBS检查，占该分娩病房所有分娩的11%。FBS时乳酸血症发生率最高的CTG模式是晚期或重度可变减速合并心动过速（首次FBS时为20%-25%，末次FBS时为33%-49%）。在胎儿心率基线正常、变异性正常且无严重减速的情况下，97.5%的病例首次FBS时胎儿头皮血乳酸浓度正常。单纯变异性降低组的酸血症患病率没有增加，乳酸浓度中位数与正常组无差异。
在大多数情况下，单纯变异性降低不是缺氧的迹象。如果一次FBS排除了缺氧的发生，这种模式在整个分娩过程中不需要重复进行FBS监测。晚期减速和重度可变减速在相同程度上增加了产时胎儿代谢性酸血症的风险。这些减速与心动过速的组合与胎儿代谢性酸血症的发生率最高相关。
