Can bicarbonate of soda help speed up a slow labour?

I'm nearing my pregnancy due date and I've read that bicarbonate of soda could help speed up a slow labour. Why is this, and is it safe for me to take it during labour?

Susan Wray, a professor of cellular and molecular physiology at the University of Liverpool, has just led a study into the effect of bicarbonate of soda on labour.

She says: "The news about bicarbonate soda comes from a study we conducted at the University of Liverpool with the Karolinska Institute, Sweden.

"Our previous work had found that women who were progressing too slowly in labour had a uterine environment that was much more acidic than that found in any other women. This was of interest because we knew acid made uterine contractions weaken. This gave us the idea of using bicarbonate to neutralise the acid and test whether this would help speed up the labours which had arrested.

"The results were extremely encouraging - drinking a bicarbonate-rich, off-the-shelf preparation significantly helped improve labour outcome, and around 20% of these women avoided an emergency C-section.

"We always need to be extremely careful when treating pregnant women, but giving bicarbonate in the low amounts used in this study is considered a safe intervention, and many pregnant women take similar preparations as antacids. It should be noted that this was a single, small-scale study on 200 women, and we now need to test the acid neutralising idea in more women and different maternity settings," she adds. "We are also only advocating this for the 10% of women whose labours are failing, and not for the remaining 90% who will not have the misfortune of a difficult labour."