Last updated January 24, 2018 at 11:08 am
Dilation rate may be ‘unrealistically fast’ for some women
The guidelines for how long is “normal” for women in labour were established in the 1950s, and set the expectation that the cervix dilates 1 cm per hour.
A study published today in PLOS Medicine set out to find out if this rate is still relevant to the current generation of women giving birth, or whether there might be differences in different populations around the world.
The study, funded by the Bill and Melinda Gates Foundation and part of the World Health Organisations Better Outcomes in Labour Difficulty (BOLD) program, looked at 5,606 women who had spontaneous, complication-free vaginal births in Nigeria and Uganda.
This was the first attempt to assess labour patterns in African women.
They found that labour progressed more slowly that previously reported for women, no matter how many times they’d given birth previously.
The variability of how long labor takes was much greater than previously reported. Women giving birth to their first child and progressing at the slowest rates may take up to seven hours to progress from 4 cm to 5 cm, over three hours to progress from 5 cm to 6 cm, and up to nine hours to progress from 6 cm to 10 cm.
“Our labour progression data clearly demonstrate that a minimum cervical dilatation rate of 1 cm/hour throughout the period traditionally described as active phase may be unrealistically fast for some women and should therefore not be universally applied as a threshold for identifying abnormally progressing labour,” the authors say.
The classic sigmodial curve that has shaped labour management for decades was not seen at all in this data. The authors suggest that these average curves of labor time are “merely useful for illustrative purposes.”
Provided all other signs of foetal and maternal monitoring are progressing normally, simply taking a long time is not enough justification for starting to intervene to speed things up.
For long labours the authors do stress it’s important to keep monitoring to ensure that there are no complications that develop, and that the woman’s needs both physically and emotionally are being met.