[Studies on the safe limit of variable decelerations during labor].

Ninety neonates who presented variable decelerations during labor were divided into two groups, according to the one-minute Apgar scores of greater than or equal to 8 and 7 less than or equal to. Only neonates of singleton pregnancies and cephalic presentations of 34 weeks gestation or more were included in the study. Several parameters of this fetal heart rate (FHR) pattern and the presence or absence of meconium staining were compared. Followings were found to be statistically significant. 1) The duration of the variable deceleration (less than 2 hours). 2) The FHR deceleration/uterine contraction ratio (less than 80%). 3) The absence of meconium staining. An effort was made to establish safe limits of variable decelerations. These are shown in parentheses. Based on both these data and findings of others, a multifactorial scoring system named a variable deceleration score was proposed for the proper management of this FHR pattern. Five variables were selected for the system. These were: The duration of variable decelerations, the FHR deceleration/uterine contraction ratio, the duration and amplitude of dips, and the presence or absence of meconium staining. The system scores from 0 to 2 for each of five factors, and was designed to be able to predict depressed neonates with the numerical increase of the score.