A woman who snatched a newborn baby from a New York hospital in 1987 and raised the child as her own has been jailed for 12 years.

Ann Pettway, who pleaded guilty to the abduction in February, took three-week-old Carlina White from the Harlem hospital emergency department where she had been taken with a high fever.

Her real parents did not see her for 23 years until Carlina herself – who was brought up in Connecticut under the name Nejdra Nance – became suspicious and discovered her identity while browsing the website of the National Centre for Missing and Exploited Children.

In sentencing Pettway, Judge Kevin Castel said the defendant had been mentally ill and deeply depressed after three miscarriages when she decided to dress up as a nurse and carry out the abduction.

But he added that she had “inflicted a parent’s worst nightmare”.

Pettway, who had agreed to plead guilty in return for a more lenient sentence, apologised for her actions and said she still loved the woman she raised.

“All I can do now is ask forgiveness from her and her parents. It may not sound correct on paper but I am hopelessly sorry,” she wrote.

“My action led to such a huge loss for her parents, but there is nothing I can do to right this wrong that I committed.”

Carlina’s birth parents, who were reunited with their daughter in January 2011, said the sentence was too little for the years of anguish inflicted by Pettway.

“I’m broken into a million pieces,” Carlina’s mother, Joy White, told the court. “My daughter’s here, but she’s not home yet.”

Father, Carl Tyson, said: “For 23 years, Ann, you had me suffering. You put a stone in my heart.

“I know you have your family and friends here,” he told Pettway. “But they don’t know what you’ve done to me.”

Outside the court, he added: “I wasn’t able to take my daughter to school, take my daughter to day care, watch my daughter get on the bus and you know, have birthday parties with my daughter.”