Department of Obstetrics and Gynaecology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.
The Fetal Physiology and Neuroscience Group, Department of Physiology, Faculty of Medical and Health Sciences The University of Auckland, Auckland, New Zealand.
J Physiol. 2017 Dec 15;595(24):7441-7450. doi: 10.1113/JP275084. Epub 2017 Nov 2.
Fetal behavioural state in healthy late gestation pregnancy is significantly affected by maternal position overnight. Maternal left lateral position is the one most frequently adopted at sleep onset. The maternal position at sleep onset is maintained the longest overnight. Fetal state 1F is more common in maternal supine positions overnight. Fetal state 4F is less common in maternal supine sleep positions. Fetal state and maternal sleep position are independently associated with fetal heart rate variability. Maternal sleep position significantly affects fetal heart rate and heart rate variability and affects circadian fetal heart rate patterns.
Fetal behavioural states (FBS) are measures of fetal wellbeing. Maternal position affects FBS with supine position being associated with an increased likelihood of fetal quiescence consistent with the human fetus adapting to a lower oxygen consuming state. Several studies have now confirmed the association between sleep position and risk of late intrauterine death. We designed this study to observe the effects of maternal sleep positions overnight in healthy late gestation pregnancy. Twenty-nine healthy women had continuous fetal ECG recordings overnight. Two blinded observers assigned fetal states in 5 min blocks. Measures of fetal heart rate variability (FHRV) were calculated from ECG beat to beat data. Maternal position was determined from infrared video recording. Compared to state 2F (active sleep), 4F (active awake-high activity) occurred almost exclusively when the mother was in a left or right lateral position. State 1F (quiet sleep) was more common when the mother was supine [odds ratio (OR) 1.30, 95% confidence interval (CI) 1.11-1.52] and less common on the maternal right side with the left being the referent position (OR 0.81, 95% CI, 0.70-0.93). State 4F was more common between 21.00 and 01.00 h than between 01.00 and 07.00 h (OR 2.83, 95% CI 2.32-3.47). In each fetal state, maternal position had significant effects on fetal heart rate and measures of FHRV. In healthy late gestation pregnancy, maternal sleep position affects FBS and heart rate variability. These effects are probably fetal adaptations to positions which may produce a mild hypoxic stress.
健康晚期妊娠胎儿的行为状态受夜间母亲体位显著影响。母亲左侧卧位是睡眠起始时最常采用的体位。睡眠起始时的母亲体位整晚维持时间最长。夜间仰卧位时胎儿状态 1F 更为常见。仰卧睡眠位时胎儿状态 4F 较少见。胎儿状态和母亲睡眠体位与胎儿心率变异性独立相关。母亲睡眠体位显著影响胎儿心率和心率变异性，并影响胎儿昼夜心率模式。
胎儿行为状态（FBS）是胎儿健康的衡量标准。母亲体位影响 FBS，仰卧位与胎儿安静的可能性增加有关，这与胎儿适应低耗氧量状态一致。多项研究现已证实睡眠体位与晚期宫内死亡风险之间存在关联。我们设计了这项研究，以观察健康晚期妊娠孕妇夜间睡眠体位的影响。29 名健康孕妇进行了整晚胎儿心电图记录。两名盲法观察者每 5 分钟记录一次胎儿状态。从心电图逐搏数据计算胎儿心率变异性（FHRV）的测量值。通过红外视频记录确定母亲的体位。与状态 2F（活跃睡眠）相比，状态 4F（活跃觉醒-高活动）几乎仅在母亲处于左侧或右侧卧位时发生。母亲仰卧位时，状态 1F（安静睡眠）更为常见[比值比（OR）1.30，95%置信区间（CI）1.11-1.52]，右侧卧位时则较少见，左侧卧位为参照体位（OR 0.81，95%CI，0.70-0.93）。状态 4F 在 21.00 至 01.00 时比 01.00 至 07.00 时更为常见（OR 2.83，95%CI 2.32-3.47）。在每个胎儿状态中，母亲体位对胎儿心率和 FHRV 测量值均有显著影响。在健康晚期妊娠中，母亲睡眠体位影响胎儿行为状态和心率变异性。这些影响可能是胎儿对可能产生轻度低氧应激的体位的适应。
