Iqbal was also quoted earlier this year in the Daily Telegraph, which identified her as one of a number of British women who wanted to return.
The Sunday Times reported that two women, who have a total of five boys under the age of eight, were also stripped of their United Kingdom citizenship after marrying into a terror cell linked with the murder of westerners.
'Any decisions to deprive individuals of their citizenship are based on all available evidence and not taken lightly, ' a spokesman added.
It reported that the sisters left for Syria in 2013.
Shamima Begum was stripped of her citizenship on security grounds last month, leaving her in a detention camp in Syria where her baby died.
Reema has one son born in the United Kingdom and another born in Syria.
Begum, a 19-year-old British teenager of Bangladeshi descent, gave birth to her son in a Syrian refugee camp in February.
"If the British Government has stripped her of her nationality, then another country should adopt her, any Muslim country".
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Republicans generally joined in the favorable vote, though almost two-dozen opposed the measure. The action had come after controversial comments by Democratic Congresswoman Ilhan Omar .
Diane Abbott, Shadow home secretary, criticised the Home Office, tweeting: "It is against worldwide law to make someone stateless, and now an innocent child has died as a result of a British woman being stripped of her citizenship".
Senior British opposition figure Diane Abbott called the United Kingdom government's decision "callous and inhumane".
Mr Phillip Lee, a former justice minister and member of Mrs May's party, said he had been deeply concerned by the decision.
Accusing Mr Javid of "moral cowardice", former director of public prosecutions Lord Macdonald said his move risked creating a "more risky world where stateless individuals roam with no allegiance and the death of unprotected innocents, in this case a vulnerable British baby".
"We further understand that indeed she and her child had been threatened by others at the Al-Hol camp".
Abbott said: "To leave a vulnerable young woman and an innocent child in a refugee camp, where we know infant mortality to be high, is morally reprehensible".
"The Home Secretary failed this British child and he has a lot to answer for".
Begum had previously given birth to two other children who are said to have died, apparently from illness and malnutrition.
But he added that Britons had been warned since 2011 not to travel to Syria because of the conflict there.
It has been claimed that Ms Begum has received death threats from other jihadi brides as she is thought to have disgraced their cause and ideals.