Correlation between umbilical cord length and gross fetal movement as counted by a fetal movement acceleration measurement recorder

INTRODUCTION: The fetal movement acceleration measurement (FMAM) recorder has made it possible to count gross fetal movements over many hours. Our purpose was to examine the relationship between umbilical cord length and fetal movements as counted by the FMAM recorder. METHODS: Sixty-two pregnant women recorded fetal movements weekly from 28 weeks to term. The ratio of 10-s periods in which movement occurred to total time was calculated as a movement index. Umbilical cord length was measured at delivery. (1) Multiple linear regression analyses were conducted with six explanatory variables (primipara / multipara, anterior / posterior located placenta, placental weight, the mean movement index of 28–31, 32–35, and 36–39 week) and a response valuable (umbilical cord length). (2) All women were divided into groups of shorter, middle, and longer cord length, specifically less than 50 cm, between 50 and 60 cm, and more than 60 cm. The movement index was compared among the three groups at 28–31, 32–35, and 36–39 weeks. RESULTS: A total of 2355.6 h from 368 night records were available. (1) There were no relationships between the cord length and the movement index of 28–31, 32–35, and 36–39 weeks (p = 0.090, 0.235, 0.129, respectively). (2) There were no differences in the movement index among the three groups at 28–31 and 32–35 gestational weeks (p = 0.096, and 0.465, respectively); however, the longer cord group had a greater movement index than the other two groups at 36–39 weeks (p = 0.0008). DISCUSSION: This study suggested that fetal movement near term is an important factor in determining whether cord length becomes relatively longer in normal pregnancies.