More than 15,000 expectant parents have had their data compromised after a hack on a leading childbirth charity.
The National Childbirth Trust (NCT) apologised to users, informing them that their email addresses, usernames and passwords had been accessed in a data breach.
The incident, which involved 15,085 users' registration details being hacked, has been reported to police and the UK's data watchdog.
No personal or financial information was accessed.
A spokesman said: "NCT has suffered a data breach which, regrettably, has caused some users of our website to have their registration details compromised.
"These details are limited to their email address, username and an encrypted version of the password that they created to register on the site.
"We stress that no financial or personal details are held as part of this data so no financial or personal details have been accessed.
"We discovered the breach (on Wednesday), upon which we contacted everyone affected advising them of the breach and suggesting that they change their username and passwords. We have also reported the matter to the police and Information Commissioner."
The London-based charity for new and expectant parents, which supports hundreds of thousands of people, sent an email to affected users on Wednesday to inform them of the incident.
However, there are several posts on the NCT's Facebook page on April 3 from users about the hack.
To these comments the charity page responded: "Thanks for letting us know. Yes, we are aware our website went down over the weekend but it is now up and running."
There are also reports from users on social media complaining about spam emails.
On Wednesday, the site put out a statement on social media which read: "Our website is back online but there may be some further disruptions today. If you have any problems, please try again later."