Low J A, Cox M J, Karchmar E J, McGrath M J, Pancham S R, Piercy W N
Am J Obstet Gynecol. 1981 Feb 1;139(3):306-10. doi: 10.1016/0002-9378(81)90015-6.
The effect of maternal labor, and fetal characteristics upon fetal heart rate behavior during the intrapartum period has been studied in 400 patients. Abnormal labor in comparison to normal labor has a higher baseline fetal heart rate with an increased incidence of baseline tachycardia and an increased incidence of absent or decreased baseline variability. A decreasing fetal weight gestational age percentile is associated with an increased incidence of variable decelerations. Segmental epidural and Demerol analgesia carefully administered has little effect upon fetal heart rate behavior.