Shamima Begum, whose fate has stirred controversy ever since she and two friends fled London to join the terror network in 2015 aged just 15, told Sky News she had delivered a boy.
"I just gave birth so I'm really tired," the 19-year-old said, as she made a renewed appeal to be allowed back to Britain with her newborn baby.
"I'm afraid he might even die in this camp. I feel a lot of people should have sympathy for me, for everything I've been through," she said.
"I didn't know what I was getting into when I left. I just was hoping that maybe for the sake of me and my child they let me come back."
Her case comes as European nations struggle with how to deal with jihadists eager to return home following the disintegration of Islamic State's "caliphate" in eastern Syria.
US President Donald Trump has again demanded that they take back hundreds of captured IS fighters.
Trump said on Twitter that the United States was asking Britain and other continental allies "to take back over 800 ISIS fighters that we captured in Syria and put them on trial".
The demand came as he prepared, ahead of the pullout of US troops, to declare the group's so-called "caliphate" destroyed, with US-led Arab and Kurdish forces close to capturing its last Syrian territorial holdout.
"The US does not want to watch as these ISIS fighters permeate Europe," Trump said.
"Time for others to step up and do the job that they are so capable of doing. We are pulling back after 100% Caliphate victory!"
'I don't regret it'
Begum, previously gave birth to two other children after marrying in Syria. Both children died.
Leading politicians, including interior minister Sajid Javid, have vowed to prevent her return, pointing to her lack of remorse for joining the terror group.
Begum told Sky News she was aware of IS's brutal tactics, including conducting beheadings, but did not regret going to Syria.
"I knew about those things and I was OK with it at first," she said.
CCTV footage of (left to right) Amira Abase, Kadiza Sultana, and Shamima Begum before catching a flight to Turkey in 2015 Source: LONDON METROPLITAN POLICE
"They take care of you... you're living under Islamic law.
"I don't regret it because it's changed me as a person, made me stronger, tougher."
The teenager, who said she had had no contact with British officials, added the government should not block her homecoming because she was "just a housewife" while there.
"I never made propaganda, I never encouraged people to come to Syria.
"They don't really have proof that I did anything that is dangerous," she said.
