Mother Sophie Dumas, 41, is considering freezing the eggs of her five-year-old daughter Sienna after she began going through puberty at just 10 months old. Sophie was unaware her daughter had any health issues as a baby until a health visitor noticed Sienna had enlarged breast tissue. A general practitioner referred them to paediatric endocrinologists, who diagnosed Sienna with central precocious puberty (CPP), a condition in which the brain begins sending the signals that trigger puberty much earlier than usual. "Sienna was a happy and healthy baby," Sophie, from London, says. "The breast buds weren't something I'd noticed before, and as babies are usually the sort of chubby that makes them that little bit more adorable, and also that she was breastfed, I didn't think anything of her appearance as being out of the ordinary." The tests Sienna had to undergo were "horrible" for the family. "She had what was referred to as Stim tests, which was a term I went on to dread," Sophie explains. "This involved blood tests to take a baseline to measure the LH level, the hormone that regulates puberty, then injecting her with a synthetic hormone to see how her blood hormones react over a period of different timeframes." "This meant a whole day in hospital. Sienna became so stressed that she sweated the cannulas out, and one of her veins collapsed." Doctors then resorted to drawing blood from her heel with a pin-prick, which Sophie said was "incredibly distressing" for her daughter. They also carried out X-rays to test Sienna's bone age, which involved trying to keep her still. "The only way I could soothe Sienna through procedures and tests was to breastfeed her in all sorts of strange positions and with one of those heavy blankets over me," Sophie explains. A few weeks later, the family received the news that Sienna's tests were positive for precocious puberty. Sophie says she'd never heard of the condition and was left desperately researching what this meant for Sienna. "I found that the lack of knowledge about it very hard, and the only parents I could find to talk to were via Facebook groups for it, but even then, they were parents of seven- to eight-year-olds, so it was never relevant," she explains. "It feels very isolating, and I still have so many questions about it, mostly about how I can explain this to Sienna." The little girl needed regular injections of a hormone blocker known as a GnRH analogue to suppress the hormones responsible for puberty, and also underwent an MRI to determine if her condition was linked to abnormalities in the brain. Without treatment, Sienna, now five, would have progressed through puberty years before her peers. While the condition is not life-threatening, doctors explained that early puberty can affect final adult height because children initially grow rapidly but their growth plates can mature sooner. "The emotional impact this may have on Sienna could be devastating," Sophie says. "Having any sorts of differences today can lead to all sorts of bullying, isolation and mental health issues." "We all want our children to remain children for as long as we can, to maintain those magical dreams and nurture vivid imaginations with fairies and princesses, so Sienna's body trying to rob her of her youth felt unfair." "CPP is certainly not life-threatening, but it is somewhat life-changing. We are incredibly lucky to have a healthy, happy daughter, so we can't complain." Sienna now has an injection every four weeks, and will do until she's 11 or 12, which she sometimes struggles with. "There are still lots of occasions where she kicks, screams, hides and as her parent, it's a labour of love, knowing it's best for her, but it does kill you inside," Sophie adds. Sophie is now looking ahead to her daughter's future and is considering whether egg freezing could give Sienna more options when she is older. "I'm currently looking into that possibility in case her condition affects her fertility later down the line," she admits. "When she was diagnosed, I was worried that she may not be able to start a family of her own one day if she wanted to, that the choice may be taken away from her." "Hopefully, the hormone blockers will prevent this from affecting her fertility." Sienna now has some untreatable symptoms like acne that are linked to her hormones and has been teased at school because classmates think she has chickenpox. "It makes me really sad," Sophie says. "No one wants to think of their child being upset, especially when it's from what someone else has said to them." "Sienna was confused because she didn't know how to explain to them that they're different kinds of spots because she doesn't even understand it." For now, Sophie wants her daughter to experience just being a child. "My main concerns are that all little girls want to grow up before they should, and the pressures around things like breast size, so I am worried that once Sienna understands what would happen if she were to refuse her treatment early so that she goes through puberty, her mental maturity wouldn't be ready for all that comes with it," she says. "The only advice I would give to another parent who is concerned about anything, even if they think it makes them look or sound neurotic, is to seek that medical advice and even get second opinions."