Almost one in 500 babies in hospitals in England is born dependent on substances their mother took while pregnant, a BBC investigation has found.
Of 72 NHS hospital trusts who responded to a Freedom of Information request, the average rate for babies born with neonatal abstinence syndrome was 0.2%.
It is caused by women taking legal and illegal drugs while pregnant.
Health experts say it is a declining trend.
BBC's Look North and the English regions data unit asked NHS hospital trusts to provide details about the number of babies born who were addicted to drugs between 2011 and 2015.
The figures show a wide geographical variation in the number of newborns who were dependent on harmful substances.
One in 100 babies born at Bedford Hospital in 2015 displayed signs of neonatal abstinence syndrome. In contrast, Leicester General had one of the lowest rates with one in every 5,000 babies born addicted to a harmful substance.
In Leeds, around one in 250 babies was born with the condition.
Lisa Batty, 37, from Bradford, gave birth to four children who were addicted to heroin.
"I didn't care that my kids were addicted to drugs, I was more concerned about where I was getting my next fix from. I know it's selfish but that's how it felt at the time," she said.
"I remember visiting my children in hospital as they suffered withdrawal symptoms from the methadone they were being given as part of their treatment. I remember seeing them trembling and shaking in their cots. I admit I was a bad mum but I've turned my life around now".
Lisa has now recovered from drug addiction and has become involved with the charity Narcotics Anonymous to help others.
The data for England also shows that over the past four years there has been general decline in the number of babies being diagnosed with neonatal abstinence syndrome.
Those working to treat mothers and babies with a drug addiction say the majority of parents they deal with come from a disadvantaged socio-economic background, with most cases involving an abuse of drugs like heroin, cocaine or alcohol.
Susan Flynn is a specialist midwife in Leeds who helps treat mothers who have a drug addiction.
"I have seen the numbers begin to fall slightly in the past three years," she said. "I don't think we can say there is one single reason for the decline but maybe the message is getting out there that it's not right to take drugs or alcohol whilst you're pregnant.
"There are of course people who say that women who take drugs whilst they're pregnant should have their children removed from them, but for me I believe everyone should have the chance to turn their life around."
Liz Butcher, from Public Health England in Yorkshire and the Humber, said: 'It is particularly important pregnant women who use drugs get supportive, collaborative care to reduce the risks to the health of their babies.
"Many places in the region have specialist staff and well-established training to make sure that happens."