van de Pas M, Nijhuis J G, Jongsma H W
Department of Obstetrics and Gynaecology, University Hospital St-Radboud Nijmegen, The Netherlands.
Early Hum Dev. 1994 Dec 16;40(1):29-38. doi: 10.1016/0378-3782(94)90097-3.
The development of fetal behaviour and of fetal behavioural states (FBS) has been well defined in preterm and term fetuses. However, FBS have not yet been studied after term, although this is a potentially very dangerous period and clinical management is controversial. We investigated fetal behaviour in normal pregnancies after 41 weeks of gestation (287 days, menstrual age, GA) as compared to control term fetuses. Furthermore, we wanted to see if the findings might have consequences for clinical management. Twelve healthy women with GA between 289 and 298 days participated. All pregnancies were reliably dated and at the time of the study, there was a normal amount of fluid. Twelve healthy women with GA 273-287 days served as controls. All subjects underwent a behavioural study using cardiotocography to record the heart rate (CTG), and two ultrasound scanners to observe body and eye movements, as described previously. All fetuses in both groups clearly exhibited FBS 1F-4F which fitted the definitions of Nijhuis et al. The median percentage of FBS 3F and 4F ('awake states') increased significantly from 6% in the term group to 21.5% in the fetuses after 41 weeks (P = 0.014). FBS 1F ('quiet sleep') and 2F ('active sleep') decreased from 92 to 78% (P = 0.014), mainly at the expense of FBS 2F which decreased from 78 to 58% (P = 0.002). This indicates increasing wakefulness in utero. The fetal heart rate patterns (FHRP) associated with FBS 3F and 4F were impressive. For example, in FBS 4F, the FHRP showed large amplitude, prolonged accelerations which fused into a sustained tachycardia with only short periods of return to the baseline, resembling tachycardia with decelerations. We conclude that in normal pregnancies after 41 weeks, the development of the fetal central nervous system continues, resulting in an increasing percentage of 'fetal wakefulness'. The CTG-patterns that result from these behaviours can easily mimic fetal distress and one should be aware of this phenomenon. Whether behavioural studies can be used to distinguish 'normal' from 'abnormal' fetuses after term awaits further study.
胎儿行为及胎儿行为状态（FBS）在早产和足月胎儿中的发育情况已得到明确界定。然而，尽管足月后是一个潜在的非常危险的时期且临床管理存在争议，但FBS在足月后尚未得到研究。我们调查了妊娠41周（月经龄287天，GA）后的正常妊娠胎儿的行为，并与足月对照胎儿进行比较。此外，我们想看看这些发现是否会对临床管理产生影响。12名月经龄在289至298天之间的健康女性参与了研究。所有妊娠的孕周均经可靠确定，且在研究时羊水适量。12名月经龄273 - 287天的健康女性作为对照。所有受试者均按照先前描述的方法，通过胎心监护记录心率（CTG），并使用两台超声扫描仪观察身体和眼睛运动，进行行为学研究。两组中的所有胎儿均清晰表现出符合尼胡伊斯等人定义的1F - 4F胎儿行为状态。3F和4F（“清醒状态”）胎儿行为状态的中位数百分比从足月组的6%显著增加至41周后胎儿的21.5%（P = 0.014）。1F（“安静睡眠”）和2F（“活跃睡眠”）从92%降至78%（P = 0.014），主要是2F减少，从78%降至58%（P = 0.002）。这表明子宫内胎儿的清醒程度增加。与3F和4F胎儿行为状态相关的胎儿心率模式（FHRP）令人印象深刻。例如，在4F胎儿行为状态中，胎儿心率模式显示出大幅度、持续时间长的加速，融合成持续性心动过速，仅有短暂的恢复到基线期，类似于伴有减速的心动过速。我们得出结论，在妊娠41周后的正常妊娠中，胎儿中枢神经系统持续发育，导致“胎儿清醒”的百分比增加。由这些行为产生的CTG模式很容易模拟胎儿窘迫，人们应该意识到这一现象。足月后行为学研究能否用于区分“正常”和“异常”胎儿还有待进一步研究。
