Department of Gynecology and Obstetrics, Peking University Third Hospital, Peking University, Beijing, China.
Department of Gynecology and Obstetrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
J Matern Fetal Neonatal Med. 2022 Dec;35(25):5506-5512. doi: 10.1080/14767058.2021.1887120. Epub 2021 Feb 17.
With computerized analysis of fetal heart rate(FHR) data from long-range monitoring, we aimed to comprehensively clarify the characteristics of FHR with increasing gestational age in low-risk pregnant women during the third trimester of pregnancy.
This was an observational study. 85 fetuses of low-risk pregnant women were included. The data covered 28 ∼ 40 weeks of gestation, and 125 cases of FHR monitoring from 85 fetuses were totally collected. The FHR baseline rate, variability, and acceleration were computationally calculated, analyzed and compared.
The average effective monitoring time for each case was 13.9 ± 4.3 h. FHR baseline gradually decreased as the gestational age progressed, and the maximum FHR baseline appeared at 28-29 weeks, which was 137.5 (133.0, 141.3) bpm, whereas the minimum FHR baseline appeared at 38-39 weeks, that was 132.8 (128.1, 138.4) bpm. FHR variability fluctuated in (4-12）bpm. It gradually increased from 28 to 33 weeks of gestation, reached the maximum of 7.6 (6.0-9.4) bpm, and then decreased until full-term pregnancy. The moderate variability proportion of FHR gradually increased from 28 weeks of gestation, peaked at 32-33 weeks as 65.8%, and then gradually decreased to 56.2% at 37 weeks, which was maintained at this level until 39 weeks. The variation tendency of minimal variability proportion was opposite to moderate variability proportion. When it reached 40 weeks, the minimal and moderate variability proportions were 50.0% and 49.0%, respectively. The FHR acceleration area showed no trend change during the third trimester, while fluctuated in (29.5-42.4) lattices/h.
This study revealed that the characteristics of FHR gradually changed with increasing gestational age, and the most obvious change was observed at 32-33 weeks, demonstrating that the specific gestational weeks may be an important period for the physiological bias of FHR tends to mature.
通过对远程监测的胎儿心率（FHR）数据进行计算机分析，我们旨在全面阐明孕晚期低危孕妇 FHR 随胎龄增加的特征。
这是一项观察性研究。纳入 85 例低危孕妇的胎儿。数据涵盖 28 周至 40 周，共采集 85 例胎儿 125 例 FHR 监测。计算、分析和比较 FHR 基线率、变异度和加速度。
每个病例的平均有效监测时间为 13.9±4.3 h。FHR 基线随胎龄的增加而逐渐降低，最大 FHR 基线出现在 28-29 周，为 137.5（133.0，141.3）bpm，而最小 FHR 基线出现在 38-39 周，为 132.8（128.1，138.4）bpm。FHR 变异度在（4-12）bpm 之间波动。它从 28 周到 33 周逐渐增加，达到最大值 7.6（6.0-9.4）bpm，然后下降直到足月妊娠。FHR 中度变异度的比例从 28 周逐渐增加，在 32-33 周达到 65.8%的峰值，然后逐渐下降到 37 周的 56.2%，并保持在这一水平直到 39 周。最小变异度比例的变化趋势与中度变异度比例相反。当达到 40 周时，最小和中度变异度比例分别为 50.0%和 49.0%。FHR 加速度区域在孕晚期无趋势变化，波动在（29.5-42.4）格/小时。
本研究表明，FHR 的特征随胎龄的增加逐渐变化，最明显的变化发生在 32-33 周，表明特定的孕龄可能是 FHR 生理偏倚趋于成熟的重要时期。
