The Primesight and Clear Channel billboards, which were booked through Signposter.com, feature the images to highlight the stigma and perceptions about pregnancy and birth.
The childbirth charity's campaign was launched today (18 November) by TV presenter Kate Garraway and aims to encourage people to discuss the pregnant form and the lack of drug-free birth options available to mothers.
The photographs used in the billboards were taken by society photographer Joth Shakerley, whose mother committed suicide after suffering from post-natal depression, and are taken from his forthcoming book Pregnant Women.
The billboards include the slogans Pregnant Women: Beautiful?, Pregnant Women: Be Proud? and Pregnant Women: A celebration?, along with the profile of a naked pregnant woman in front of a natural landscape.
Jenny Smith, midwife, mother of four and founder of The Jentle Childbirth Foundation, said these posters were "beautiful portraits of the most natural and essential experience that life can offer".
The Foundation provides information and advice to parents about pregnancy and researches methods and environments that support positive pregnancy and birth experience.