Mum considering freezing daughter's eggs after she started puberty at just 10 months

Tuesday, September 22, 2026 -A mum is considering freezing her young daughter's eggs after she started going through puberty at just 10 months old 

Sophie Dumas had no idea that anything was unusual about her daughter, Sienna, until a health visitor noticed that the baby's breast tissue appeared enlarged. 

The mum took her daughter to the GP and she was referred to paediatric endocrinologists. After a series of tests, Sienna was diagnosed with central precocious puberty (CPP) – a condition in which the brain begins sending the signals that trigger puberty early. 

She was just 10 months old at the time. 

“Sienna was a happy and healthy baby,” said Sophie, from London. “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 she underwent were horrible for all of us. She had what was referred to as Stim tests, which was a term I went on to dread, which 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. 

“They then had to draw her blood via another method from her heels with a pin-prick. 

“It was incredibly distressing. They had to carry out X-rays to determine Sienna’s bone age, which was awful as they needed her to keep her hand flat and still whilst the X-rays were taken. 

“That’s not easy for a 10-month-old to do. 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.

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. 

She said: “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. It feels very isolating, and I still have so many questions about it, mostly about how I can explain this to Sienna.”

Doctors explained that she would need regular injections of a hormone blocker known as a GnRH analogue to suppress the hormones responsible for puberty. Sienna also underwent an MRI to determine whether there was an underlying cause for her condition. 

In some cases, central precocious puberty can be linked to abnormalities in the brain. Sophie said the possibility was “terrifying”. 

Thankfully, Sienna's MRI was clear, and she was diagnosed with central precocious puberty, which has no known cause in many children and is more common in girls. 

Without treatment, Sienna, who is now five years old, would have progressed through puberty years before her mates. 

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. 

Sophie said: “The emotional impact this may have on Sienna could be devastating. 

“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. 

“However, when it’s your daughter who you have to hold down so the doctors can take bloods or give her injections, and she’s crying, ‘Mummy, please help me, please don’t let them hurt me’, it is heartbreaking. I also can’t tell her that she needs to have these injections to stop her getting sick, as this is untrue. 

“Sienna now has an injection every four weeks. Sometimes she’s absolutely fine about them, but 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.” 

The family has been told that Sienna is likely to remain on the hormone-blocking treatment until she is around 11 or 12, although this will depend on her bone age and how she develops. 

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. 

She said: “I’m currently looking into that possibility in case her condition affects her fertility later down the line. 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’s getting to an age where some of the untreatable symptoms are causing her to deal with spots on her face in the areas that are linked to hormones.

“It’s difficult explaining it to her. There’s been some teasing from her school friends who have said they think she has chickenpox. It makes me really sad. 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. I told the teacher, who said that she knew they were hormonal spots and that she would reassure Sienna and tell the other children that it’s not their job to play doctor.” 

For now, Sophie says she is determined to let her daughter enjoy being a little girl. 

She added: “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. 

"Puberty is such an abstract concept for a child, so talking to her about it is complicated for her to understand and also for me to explain. Sienna is still a little girl, obsessed with fairies and Disney princesses, and I’d love to take her to Disneyland next year to keep the magic of childhood alive for as long as possible. 

“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. 

“Our health visitor didn’t even think it would get taken seriously and, without her noticing something I never did, Sienna would not have received treatment as early as she did.”