Parer J T, King T, Flanders S, Fox M, Kilpatrick S J
Department of Obstetrics, Gynecology and Reproductive Sciences, University of California San Francisco, CA 94143-0132, USA.
J Matern Fetal Neonatal Med. 2006 May;19(5):289-94. doi: 10.1080/14767050500526172.
Despite the ubiquity of electronic fetal monitoring, the validity of the relationship between various fetal heart rate (FHR) patterns and fetal acidemia has not yet been established in a large unselected series of consecutive pregnancies. The aim of this study was to examine the published literature for evidence of such a relationship.
Four hypotheses based on assumptions in common clinical use were examined. The literature was searched for relationships between certain aspects of FHR patterns (e.g., degree of FHR variability, depth of decelerations), and fetal acidemia, or fetal vigor (5-minute Apgar score >or=7). We also attempted to relate duration of these patterns to the degree of acidemia. Using standardized FHR nomenclature we defined patterns based on baseline FHR variability, baseline rate, decelerations, and accelerations.
The following relationships were observed: (1) Moderate FHR variability was strongly associated (98%) with an umbilical pH >7.15 or newborn vigor (5-minute Apgar score >or=7). (2) Undetectable or minimal FHR variability in the presence of late or variable decelerations was the most consistent predictor of newborn acidemia, though the association was only 23%. (3) There was a positive relationship between the degree of acidemia and the depth of decelerations or bradycardia. (4) Except for sudden profound bradycardia, newborn acidemia with decreasing FHR variability in combination with decelerations develops over a period of time approximating one hour. Most studies identified were observational and uncontrolled (grade III evidence of US Preventive Services Task Force); however, there was general agreement amongst the various studies, strengthening the validity of the observations.
The validity of the relationship between certain FHR patterns and fetal acidemia and/or vigor, is supported by observations from the literature. In addition four assumptions commonly used in clinical management are supported. These conclusions need to be confirmed by a prospective examination of a large number of consecutive, unselected FHR patterns, and their relationship to newborn acidemia. Pending the completion of such studies, these observations can be used to justify certain aspects of current clinical management, and may assist in standardizing the diversity of opinions regarding FHR pattern management.
尽管电子胎儿监护已广泛应用，但在大量未经筛选的连续妊娠病例中，各种胎儿心率（FHR）模式与胎儿酸血症之间关系的有效性尚未确立。本研究的目的是检索已发表的文献，寻找这种关系的证据。
对基于临床常用假设的四个假说进行了检验。检索文献，查找FHR模式的某些方面（如FHR变异性程度、减速深度）与胎儿酸血症或胎儿活力（5分钟Apgar评分≥7）之间的关系。我们还试图将这些模式的持续时间与酸血症程度联系起来。使用标准化的FHR命名法，我们根据基线FHR变异性、基线率、减速和加速来定义模式。
观察到以下关系：（1）中度FHR变异性与脐动脉血pH>7.15或新生儿活力（5分钟Apgar评分≥7）密切相关（98%）。（2）在存在晚期或变异减速的情况下，无法检测到或最小的FHR变异性是新生儿酸血症最一致的预测指标，尽管关联度仅为23%。（3）酸血症程度与减速或心动过缓的深度之间存在正相关关系。（4）除了突然严重心动过缓外，伴有FHR变异性降低和减速的新生儿酸血症在大约一小时的时间内逐渐发展。大多数纳入研究为观察性且无对照（美国预防服务工作组III级证据）；然而，各研究之间普遍存在共识，加强了观察结果的有效性。
文献观察结果支持某些FHR模式与胎儿酸血症和/或活力之间关系的有效性。此外，临床管理中常用的四个假设也得到了支持。这些结论需要通过对大量连续、未经筛选的FHR模式及其与新生儿酸血症的关系进行前瞻性研究来证实。在完成此类研究之前，这些观察结果可用于证明当前临床管理的某些方面合理，并可能有助于规范关于FHR模式管理的不同观点。
