A simulation study using regression techniques.
We created a simulated data set for 500 000 labours with clearly defined latent and active phases using the parameters described by Friedman. Additionally, we created a data set comprising 500 000 labours with a progressively increasing rate of cervical dilatation.
Repeated-measures polynomial regression was used to create summary labour curves based on simulated cervical examinations. Interval-censored regression was used to create centimetre-by-centimetre estimates of rates of cervical dilatation and their 95th centiles.
Labour summary curves and rates of cervical dilatation.
Repeated-measures polynomial regression did not detect the rapid acceleration in cervical dilatation (i.e. acceleration phase) and overestimated lengths of labour, especially at smaller cervical dilatations. There was a two-fold overestimation in the mean rate of cervical dilatation from 4 to 6 cm. Interval-censored regression overestimated median transit times, at 4- to 5-cm cervical dilatation or when cervical examinations occurred less frequently than 0.5- to 1.5-hourly.
Repeated-measures polynomial regression and interval-censored regression should not be routinely used to define labour progress because they do not accurately reflect the underlying data.
Repeated-measures polynomial and interval-censored regression techniques are not appropriate to model first stage of labour.
使用回归技术的模拟研究。
我们使用Friedman描述的参数为500.000劳动力创建了一个模拟数据集,该数据集具有明确定义的潜在和活动阶段。此外,我们创建了一个数据集,该数据集包含50,000个劳动,宫颈扩张率逐渐增加.
根据模拟宫颈检查,使用重复测量多项式回归来创建总结产程曲线。间隔删失回归用于创建对宫颈扩张率及其第95百分位数的逐厘米估计。
产程总结曲线和宫颈扩张率。
重复测量多项式回归没有检测到宫颈扩张的快速加速(即加速阶段)和高估的产程长度,尤其是在较小的宫颈扩张时。宫颈扩张的平均速率从4到6cm高估了两倍。区间删失回归高估了过境时间中位数,在宫颈扩张4至5厘米或宫颈检查发生频率低于0.5至1.5小时时。
重复测量多项式回归和区间删失回归不应常规用于定义劳动进度,因为它们不能准确反映基础数据。
重复测量多项式和区间删失回归技术不适合对第一产程进行建模。