
The redesign includes new content across such areas as conception, pregnancy, babies, information on toddlers and books, with further new content planned in the future.
The company, set up by sport's journalist Justine Roberts and TV producer Carrie Longton, claims the redesign has made navigating around the site easier for users.
Roberts said: "We've had pretty much the same design since we launched in 2000 and we felt it was time for a fresher, less cluttered look."
Coinciding with the redesign, the company has decided to bring the majority of its sales operation in-house, having previously worked with OTP Media.
Sales to agencies including OMD and Manning Gottleib OMD, Carat and Starcom will now be moved in-house, headed Jules Kendrick. Roberts said the four-strong team is likely to double. OTP Media will continue to be responsible for remaining agency sales.
Mumsnet claims to reach 850,000 unique users, generating16 million page impressions each month.