The Mumsnet Pregnancy Tracker by DigitasLBi aims to show that pregnancy is not a textbook process.
The free iPhone app features a weekly calendar of medical facts and advice from other mothers. It encourages mums-to-be to share images of their bump and their experiences on an online forum.
Justine Roberts, the chief executive at Mumsnet, said: "We’ve worked in partnership with DigitasLBi to create an app which brings to life the unspoken truths and diverse experiences of pregnancy, enabling pregnant women and their partners to benefit from the wisdom of our brilliant community.
"It’s another way in which we’re trying to fulfill our mission of making parents’ lives easier."
Sergio Falletti, the technology partner at DigitasLBi, said: "Mumsnet Pregnancy Tracker brings the wisdom of the crowd to a space which is currently dominated by very sanitized, one-size-fits-all content.
"We’re excited to see parents-to-be interacting with the Mumsnet community and enjoying the depth of content it offers in a safe and convenient format."