When her daughter Ember was born 13 months ago, Gina Cox-Roberts, a natal hypnotherapist from Telford, had an overwhelming sense that the placenta was part of the baby's body. "The placenta and the child came from the same cell," she says. "Her placenta was as much a part of her as her hands or her heart." So why cut the umbilical cord? Instead Cox-Roberts decided to go ahead with a "lotus birth" - a practice in which the placenta stays attached to the baby until the umbilical cord disintegrates naturally a few days later.

Cox-Roberts believes that this approach - which followed an uncomplicated home birth attended by an independent midwife - gave her baby the opportunity to "let go" of the cord and placenta in her own time. "After all, her entire existence until the moment of birth was next to this placenta, which she would snuggle up to. The placenta had been her companion, her plaything: its sounds had lulled her to sleep. Here she was in this alien world and we were going to cut away the one thing she knew. Why do we feel we have a right to do that?"

Thanks to the rise of online home birthing groups, lotus birth is enjoying a revival. The expression comes from Buddhism - meaning "holy, intact child" - and while the practice was once common in Bali and various aboriginal cultures, its origins are uncertain. Now it has the seal of approval from French birthing guru Michel Odent, who has said that "we need to relearn what birth can be like when it is not disturbed by the cultural milieu. We need a reference point from which we should try not to deviate too much. Lotus birth is such a reference point."

In Australia in particular, where there is a growing home birth support network, the practice is hotly discussed. There is a book on the topic, Lotus Birth by Shivam Rachana, and the movement even has a poster girl in Dr Sarah Buckley, a GP with four children between the ages of eight and 18, three of them lotus births.

Mothers who take this approach often personify the placenta, treating it almost like a baby itself: "Be nice, use warm water to wash it!" advises one website. Cox-Roberts feels that treating the placenta with respect makes the transition from womb to world much easier for the baby. "After two and a half days, Ember's cord fell away at the navel and she had a perfect belly button," she says. "It was a little bit red but not sore or open. It looked exactly like a baby's belly button when a cord stump [the remnant of a cut umbilical cord] comes away - and that can take up to 10 days."

She says that it is not inconvenient to carry the cord, placenta and baby around together. "We rinsed off the placenta so it was as clean as possible. We sprinkled sea salt over it - it's a chunk of meat quite like liver and has the potential to go off. We had some lavender essential oil to drip on it too in case it got smelly, but it never did. We wrapped it in a terry nappy, then wrapped the baby and the placenta up together in a sleeping bag. Every 12 hours we changed the nappy and added more salt. It worked fine." She and her partner Rae, a psychologist, are keeping the placenta in the freezer until they move house - then they will plant it beneath a tree.

Unsurprisingly, lotus birth is a minority home birth activity, says Mervi Jokinen of the Royal College of Midwives, although there is no reason you couldn't ask for it at a hospital birth. "The people who do this are happy to see the experience as a life event and a natural thing. It's difficult to make a clinical comment on this because there are no studies." Jokinen is not in a position to vouch for its total safety, she says, since, "The placenta is a blood organ and bacteria can set in quickly with a blood organ."

The usual process in a birth, of course, is to cut the umbilical cord and then deliver the placenta as quickly as possible. In the majority of today's hospital births an injection of syntometrine is administered once the cord has been cut, to speed up contractions and ensure that the placenta is delivered within minutes, minimising the risk of bleeding. If you don't have this injection, the placenta comes out at its own rate - which usually takes about an hour (in Cox-Roberts' case, it took five).

Jokinen says that the practice of cutting the cord and administering syntometrine developed because it lessened the risk of post-partum haemorrhage, which was once the most common cause of death in childbirth. "This reduced the maternal mortality rate so rapidly that it was adopted everywhere." she says. Natural birth advocates - including lotus birthers - argue that this is no longer necessary: now that women are healthier, have smaller families and are less likely to be anaemic, there is no reason to adopt these methods as standard.

Lisa Schuring, an Australian who runs the Joyous Birth website, has two children, aged three and five, both of them lotus births. She sees the approach as safe and sensible, and says there was no way she was going to sever her babies' connection to their placenta. "My first child used to sleep with her fingers curled around the cord. The cord was dried and ready to come off after three days but she kept holding on to it until about seven days after birth. Then she pulled it off herself. She also did not like anyone but me touching the placenta."

Buckley says there are health benefits to lotus birth: "The baby receives an extra 50-100ml of their own blood, known as the placental transfusion, which contains iron, red cells, stem cells and other nutrients, which will benefit the baby through the first year." Lotus birthers often talk about the importance of the "babymoon": the post-birth period when the mother and baby should be together exclusively, bonding and cocooning. Lotus birth "is an ideal start", says Buckley, "because it slows everyone down: with a lotus birth, you can't take your new baby shopping". (Or rather, you could, but the placenta would have to come as well.) This is why some see lotus birth as a way of reclaiming birth as an exclusively mother-and-baby experience. It precludes the cutting of the cord, for instance, which is one common way of involving fathers in the birth, and Schuring says that lotus birth mothers tend to get their babies completely to themselves for several days. "You can avoid the "pass the baby around" thing with visitors," she says. "People are usually put off by the cord and the placenta."

Beyond the bonding, some argue that the best thing about lotus birth is that it gives you more time to decide what to do with the placenta: bury it, eat it or freeze it. The resurgence of lotus birth coincides with a rising interest in the placenta as a nutrient, with proponents claiming that it wards off post-natal depression. Ten years ago Hugh Fearnley-Whittingstall was accused of cannibalism when he fried a placenta with shallots and garlic and spread it on foccaccia. Now, however, there are thousands of recipes online for placenta smoothie, bolognese and pizza, although most prefer to eat it the old-fashioned way: raw. Celebrity placenta fans include Tom Cruise ("very nutritious") and Matthew McConaughey (who planted it beneath a tree). There is even a placenta blog: "Thanks for helping to spread the placenta love!"

Most bizarrely of all, in the wake of lotus birth another new trend has sprung up in the US: placenta encapsulation services. This involves the placenta being baked, ground into a powder and converted into pills to be swallowed. One website offering this service suggests that, "When you have recovered from childbirth, you can freeze the capsules and save them for menopause." Now there's a treat to look forward to.