A biphasic fetal heart rate variable deceleration pattern (W-sign) was investigated and found to be significantly associated with a greater length of umbilical cord (73.07 +/- 17.1 cm) than was found in patients without this pattern (56.47 +/- 11.4 cm) during the first stage of labor (P less than .001). The possible etiology of this variable deceleration pattern and its relative benignity are discussed.
对双相型胎儿心率变异减速模式（W 波）进行了研究，发现与第一产程中无此模式的患者相比，该模式与更长的脐带长度显著相关（73.07±17.1 厘米 vs 56.47±11.4 厘米，P<0.001）。讨论了这种变异减速模式的可能病因及其相对良性。
