UK-based health club operator LA Fitness has agreed to waive the membership contract of a heavily pregnant woman and her out-of-work husband following pressure from social media users and a campaign by the Guardian newspaper.

The lady, who was a member at LA Fitness' Billericay club in Essex, wrote to the Guardian's "Consumer Champions" column in January complaining that she had been unable to cancel her and her husband's 24-month contracts which made them liable to pay £780.

She said their circumstances had drastically changed as she had become pregnant and her husband had lost his job. The couple were also forced to move house which meant they lived 12 miles from the LA Fitness club they were members at.

The Guardian took up the issue and contacted LA Fitness, which agreed to a compromise and said it would only charge the couple a further six months of the contract - leaving them liable to pay £360.

However, the story was then picked up by Guardian readers and the plight of the couple spread across the social media platforms - especially on Twitter where the operator's handle "@LAfitnesstips" trended for a while.

LA Fitness attracted thousands of angry and critical tweets and comments over its handling of the situation, with a number of people offering to pay the outstanding £360 owed by the couple.

Four days after the first Guardian article appeared, however, the operator backed down and waived all of the couple's outstanding fees.

LA Fitness made the announcement using its Twitter feed in the hope of calming down what had become a social media storm against the company.

The company tweeted: "We've been in ongoing dialogue with the couple since before Christmas to with regard to this matter. The Guardian Subsequently brought to our attention new circumstances we had not been made aware of by the couple themselves.

"The couple were undoubtedly going through a difficult and distressing time. Earlier this month we reduced the length of their contract from 15 months to six months. We appreciate that their circumstances have changed dramatically since they first signed with us and at 3pm this afternoon we wrote to the couple informing them we had waived all outstanding fees.

"We would never wish to cause distress to any of our members and offer a wide variety of contract terms which are explained fully on joining. We have clear terms and conditions, allowing for early termination of any contract. This extends to both redundancy and pregnancy.

"The communication breakdown has been most regrettable and we apologise for any distress this has caused."

It is the latest example of why businesses need to be aware of the power of social media. While it can be used to great effect in attracting customers and build a brand, a badly-handled complaint or query can cause significant damage to the reputation of a business.

David Stalker, chief executive of the Fitness Industry Association (FIA), said that LA Fitness' recent experience is a perfect example of how important it is for companies to react quickly to negative exposure.

"Social media has become a key part of our sector's communications," Stalker said. "It allows the FIA and its members to use platforms such as Facebook and twitter to advocate activity directly to consumers.

"Positively this informs people where they can be active and how they can be active. Unfortunately this recent example highlights the pitfalls of instant communication, as without the full evidence and legal justification, one negative experience has been voiced and created a backlash against an operator. We must be media savvy and respond as quickly as possible to public opinion through these channels."