[The effect of the uterine contraction on the fetal heart rate pattern].

The relationship between uterine contraction and the change in the FHR pattern was investigated in term deliveries with cephalic presentation in the first stage of labor and immediately before fetal expulsion and the following results were obtained. In the first stage of labor, when the increase in the planimetric value over the value in the preceding period was defined as the increment ratio of uterine contraction (IRUC), its upper rejection limit was 22%. When IRUC was higher than the upper rejection limit, late deceleration was more frequently found than when it was within the normal range. Even in the presence of late deceleration, the fetal outcome was fairly good when IRUC was above the upper rejection limit. Melchoir's classification of the terminal bradycardia pattern immediately before fetal delivery was modified by the author and the UApH and Apgar scores were studied in accordance with the newly modified contraction types. The significance of the new classification of fetal outcome is discussed.