THE NORMAL PRETERM FETAL HEART-RATE PATTERN

A longitudinal. study was carried out on 38 women with low risk pregna ncies. These women had cardiotocography at 27-28 wk initially, at fort nightly intervals thereafter until 36 wk and at weekly intervals there after until delivery. All cardiotocographs were analyzed by one invest igator who was not aware of the individual clinical situation. Of the 232 cardiotocographs, 12 (0.5%) of poor quality were excluded from ana lyses. The mean base-line heart rate decreased from 142.5 (SD 6.03) be ats per min at 27-30 wit to 138.2 (SD 7.4) at term. Analysis of varian ce for repeated measures showed that the decrease in foetal heart rate with gestation was statistically significant (P < 0.001). The number of accelerations increased with gestation (P = 0.002). There were no s ignificant changes in variability and decelerations with increasing ge station.