Objective

To describe the duration, progression and patterns of first stage of labor among Swedish women.

Design

Population-based cohort study.

Population

Data from Stockholm-Gotland Obstetric Cohort 2008–2014 including ¼ of all births in Sweden, the final sample involved a total of 85,408 women with term, singleton, vertex, live fetuses experiencing spontaneous labor onset and vaginal delivery with normal neonatal outcomes.

Main outcome measures

Time to progress during first stage of labor using three approaches: 1) Traverse time in hours to progress centimeter to centimeter, 5^th, 50^th (and 95^th percentile); 2) Dilation curves for different percentiles, and; 3) Cumulative duration for the 95^th percentile by parity and dilation at admission.

Results

Variation in both the total duration and the trajectory of cervical change over time is large. Similar to the general held view, the rate of cervical dilation accelerates at 5–6 centimeters. Among nulliparous women, the median time found in our population was faster than their counterparts in studies conducted on American and African cohorts. Among nulliparous and multiparous women our data suggest that the median cervical change over time is faster than 1 cm per hour during the first stage of labor. However, traverse time of cervical change at and beyond the 95^th percentile is longer than 1 cm per hour.

Conclusions

Labor progression varies widely and labors experiencing a prolonged first stage can still result in normal outcomes. The assumption of 1 cm per hour cervical dilation rate for the first stage of labor may not be universally meaningful. There are differences in progression for women during first stage of labor in different populations. For prolonged labor progression to be more clinically meaningful, the association with adverse birth outcomes needs to be further investigated in specific populations.

中文翻译：

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自然分娩妇女的第一阶段进展：一项基于人群的大型队列研究

目的

描述瑞典妇女分娩第一阶段的持续时间，进展和方式。

设计

基于人群的队列研究。

人口

来自斯德哥尔摩-哥德兰产科队列2008-2014的数据包括瑞典所有分娩的1/4，最终样本涉及总计85,408名具有自然分娩，自发分娩和阴道分娩，正常新生儿分娩的胎儿。

主要观察指标

时间期间，使用三种方法劳动的第一阶段的进展：以小时1）遍历进展时间厘米至厘米，5^日，50^日（以及95^个百分位）; 2）不同百分位的膨胀曲线；以及 3）入学时通过奇偶校验和扩张的95^个百分位数的累积持续时间。

结果

总持续时间和宫颈变化轨迹随时间的变化都很大。与一般观点相似，子宫颈扩张的速度在5-6厘米处加快。在对美国和非洲同龄人进行的研究中，未生育妇女中的中位时间比同龄人中的时间要快。我们的数据表明，在未产卵和多胎妇女中，第一胎分娩期间随时间变化的中位宫颈变化速度超过每小时1厘米。但是，在第95^个百分位及更高百分数处，子宫颈变化的穿越时间超过了每小时1厘米。

结论

劳动进度差异很大，经历长期第一阶段劳动仍可导致正常结局。第一阶段分娩时宫颈扩张速度为每小时1厘米的假设可能没有普遍意义。在不同人群中，妇女在分娩的第一阶段的进展有所不同。为了使延长的分娩进程在临床上更有意义，需要在特定人群中进一步研究与不良出生结局的关系。