Health visitor saw change in baby, doctors said it was puberty at 10 months old

A mum is considering freezing her young daughter’s eggs after she started going through puberty at just 10 months old. Sophie Dumas was unaware anything was unusual about her daughter, Sienna, until a health visitor noticed that the baby's breast tissue appeared enlarged.

The 41-year-old 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.