Ms Begum was 15 when she and two other schoolgirls went to join the terror group in February 2015.
But now British Home Secretary Sajid Javid is under fire, after Begum's infant son, born around three weeks ago, fell ill and died in the Syrian camp.
Shadow home secretary Dianne Abbott blamed Javid's decision to remove Begum's citizenship for the child's death, accusing him of breaking worldwide law.
"The government will continue to do whatever we can to prevent people from being drawn into terrorism and travelling to unsafe conflict zones", he said.
The British government couldn't confirm the reports. In order to protect this country, he has the power to deprive someone of their British citizenship where it would not render them stateless.
The Foreign Secretary's defence came on Sunday after it was reported that two further women married into the terror group have been stripped of their United Kingdom citizenship while being held in detention camps with their children.
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Whilst Joe , 29, added: "We had to work through and understand what we were going through when we were that young". Nick and Chopra married in a lavish, multi-day ceremony in India in December.
Shadow home secretary Diane Abbott said the child had died as a result of the "callous and inhumane" decision to strip Ms Begum of her citizenship while Tory MP and former justice minister Phillip Lee urged the government to "reflect" on its "moral responsibility" for the tragedy.
Begum's family is challenging the U.K.'s decision to revoke her citizenship.
As the baby was born while Begum was still a British national, his status remains that of a British national.
Former director of public prosecutions Lord Macdonald accused Mr Javid of "moral cowardice" and said his move risked creating a "more unsafe world where stateless individuals roam with no allegiance and the death of unprotected innocents, in this case a vulnerable British baby".
Conservative Party chairman Brandon Lewis defended Mr Javid, telling Today: "There is no question that the duty of a home secretary in this country is to keep British people safe".
But he said it would be "incredibly difficult" to bring the child back from Syria, where Britain has no consular presence.
Despite his marriage to Iqbal, Da Costa is said to have married Natalie Bracht after grooming her on the internet.
The International Rescue Committee on Friday said that 12,000 women and children had arrived at the Kurdish-run Al-Hol camp since Wednesday.