Rossavik I K
Am J Obstet Gynecol. 1980 Mar 1;136(5):579-83. doi: 10.1016/0002-9378(80)91006-6.
Resistance to the passage of the fetus during parturition has been estimated indirectly by calculation of the active contraction area during the first stage of labor until the cervix reaches a dilatation of 5 cm--the period of cervical resistance. Parturients with a high total uterine impulse in this period were studied. Two different patterns of cervical resistance with corresponding clinical pictures were found. Type I had a high frequency of cesarean sections with a good correlation to the resistance. With high resistance there also was a tendency to low Apgar scores at 1 minute. Type II had normal 1 minute Apgar scores and only vaginal deliveries.
分娩时胎儿通过产道的阻力是通过计算第一产程中直到宫颈扩张5厘米（宫颈阻力期）的有效宫缩面积来间接估计的。对该时期总子宫冲动较高的产妇进行了研究。发现了两种不同的宫颈阻力模式及其相应的临床表现。I型剖宫产率高，且与阻力有良好的相关性。阻力高时，1分钟时阿氏评分也往往较低。II型1分钟阿氏评分正常，仅经阴道分娩。
