Women who walk, sit, kneel or otherwise avoid lying in bed during early labor can shorten the first stage of labor by about an hour, according to a new Cochrane evidence review.
Women who labored out of bed during the early stages were also 17 percent less likely to seek pain relief through epidural analgesia, the review found.
"This shortens labor by about an hour and, for a lot of women, an hour would be really important," said Teri Stone-Godena, director of midwifery at the Yale School of Nursing, who had no affiliation with the review.
Fortunately, the review did not find any differences in birth outcomes for mothers or babies due to labor position. There were no differences in terms of interventions like birth by Caesarian section. "I think this means that women can be reassured that any position that they want to get into is OK," Stone-Godena said.
Overall, the review included 21 studies, examining 3,706 births.
It appears in the latest issue of The Cochrane Library, which is a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.
So why would staying out of bed shorten labor and reduce pain?
"Women who are upright and mobile are able to change their positions more easily," said Annemarie Lawrence, lead review author and a research midwife at the Institute of Women's and Children's Health at Townsville Hospital in Queensland, Australia.
"The ability to change positions, to utilize a wider variety of positions, and try other options, such as hot showers, birthing balls and beanbag supports, may help reduce overall pain and give women a greater sense of control over the progress of their labor," she said.
When women are upright, there is also more room for the baby to move downward because the diameter of the pelvis expands slightly. This puts less pressure on nerves in the spine, which could mean less pain.
"It may also be that women are more distractible when up and moving around," Stone-Godena said. "When you are lying there looking at clock, it's a lot different from being up and about."
Being upright allows gravity to help the baby make her way into the world. Lawrence said, "The physiological advantages of upright positions and mobility include the effective use of gravity, which aids in the descent of the baby's head. As the head is applied more directly and evenly against the cervix, the regularity, frequency, strength and therefore efficiency of uterine contractions are intensified."
When the mom-to-be moves, this also helps the baby to get into the best position to hasten birth. "This improves its alignment for passage through the pelvis," Lawrence said. "There is also a psychological advantage associated with the belief that being upright and mobile empowers women to actively participate in their birth experience and maintain a sense of control."
Other research has found that feeling in control and able to make choices reduces pain and psychological distress in general.
In contrast, however, lying flat on one's back during labor can put a great deal of pressure on the blood vessels in the abdomen. "There is widely accepted physiological evidence that the supine position may be harmful in late pregnancy and labor," Lawrence said.
According to the reviewers, the supine position puts the entire weight of the pregnant uterus on the blood vessels that supply oxygen to both mother and child, which could potentially lead to problems with heart functioning in the mother and reduced oxygen to the baby. These outcomes could be serious in extreme cases. Lying on one's side has no link with such problems, however.
Stone-Godena said that despite all the attention given to empowering women to have the type of birth experience they prefer, medical professionals still pressure women into lying in bed during labor, because it is more convenient this way for nurses and doctors - and makes fetal monitoring easier.
"I think this research is very vindicating of women being allowed to assume positions of comfort," she said. "Listening to their bodies is what they need to do. Most of time when we limit people's activity, it isn't for reasons that are soundly based on evidence."
She added, "This clearly shows that there are no advantages in staying in bed unless that's where you want to be."
The Cochrane Collaboration is an international nonprofit, independent organization that produces and disseminates systematic reviews of health care interventions and promotes the search for evidence in the form of clinical trials and other studies of interventions. Visit http://www.cochrane.org for more information.
Lawrence A, et al. Maternal positions and mobility during first stage of labor. Cochrane Database of Systematic Reviews. Issue 2, 2009.