Female genital mutilation (FGM) is increasingly being performed on babies and infants in the UK, the Victoria Derbyshire programme has been told.
FGM expert and barrister Dr Charlotte Proudman said it was "almost impossible to detect" as the girls were not in school or old enough to report it.
In one report, in Yorkshire, a victim was just one month old.
The National FGM Centre said it was "not surprised" that victims may be younger now.
Charity Barnardo's and the Local Government Association - which together run the centre - said its community engagement was "key to protecting girls".
Their comments follow the first UK conviction for FGM.
The mother of a three-year-old girl was found guilty at the Old Bailey on Friday of mutilating her daughter. Her partner was acquitted.
FGM includes the partial or total removal of the female external genitalia or other injury to the female genital organs for non-medical reasons.
Dr Proudman said there was "a lot of anecdotal data which shows FGM is now being performed on babies.
"These girls are not at school, they are not at nursery, and so it's very difficult for any public authority to become aware," she added.
"By performing it at such a young age, they're evading the law."
In response to a Freedom of Information request, West Yorkshire Police said a quarter of its FGM reports (17) between 2015 and 2017 involved victims aged three or under.
The National FGM Centre said there was "anecdotal evidence from some communities that FGM laws can be circumnavigated by performing the procedure on girls at a much younger age".
"The girls are unable to report, the cut heals quicker and prosecution is much harder once evidence comes to light and the girl is older.
"There needs to be much greater recognition of this issue across different areas of the UK."
'Worried about being branded racist'
Experts say authorities need a more joined-up approach when dealing with FGM.
It is claimed children's services can be unsure when to intervene. Doctors are not always reporting it to the police - and even if they do, officers do not always know what to do.
"People are concerned about cultural sensitivities, worried about being branded racist, and it's being performed on a very private area," Dr Proudman said, explaining why it has taken many years for the first UK conviction to arrive.
Figures seen by the Victoria Derbyshire programme show that 939 calls were made to emergency services to report FGM between 2014 and 2018.
But the Crown Prosecution Service has only received 36 referrals for FGM from the police since 2010.
One 2015 report by City, University of London estimated 137,000 women and girls in England have been victims of FGM.
Hibo Wadere was six when she was forced to undergo FGM.
Some may find her words distressing.
Ms Wadere said she was told a special party was being thrown for her.
She described how that morning she was "held down, your legs yanked apart and your genitals being ripped apart.
"You saw the blood, you saw the cutter with blood on her hands," she added.
"She just kept on cutting as if it was normal for her to hear the screams.
"It was the cruellest thing for a child to experience.
"It stays with you for life. It's a life sentence."
Lawyer Linda Weil-Curiel, whose work has led to more than 100 FGM convictions in France, told the Victoria Derbyshire programme the UK should follow the country's tougher stance.
In France, all children undergo regular genital checks until the age of six and doctors are expected to report any cases of physical abuse.
"In [the UK] system you need the victim to come and complain, but how can you expect a child to complain against her parents?," she asked.
"It's for society to protect children, to take the initiative as soon as mutilation is documented - and the only way that happens is to have a medical examination.
"There might be people horrified at the thought of their child undergoing a check. I don't understand that - we are talking about the health of children and babies," she added.
But the National FGM Centre said the key way to prevent instances of the abuse was to change "the views of affected communities" and to form "a huge cultural shift in groups where FGM is commonly practised".
It said it was helping to train professionals to be "aware of how to broach the topic, spot the signs and respond appropriately when there is a concern".
Home Secretary Sajid Javid said: "We will not tolerate FGM and not rest until perpetrators of this horrific crime are brought to justice.
He said the UK's first conviction for FGM came after "the government introduced tougher rules to criminalise this medieval practice."