Watch Connect the World at 5 p.m. CET this week for detailed reports on Yazidis enslaved by ISIS and their lives now.

Dohuk, Iraq (CNN) ISIS militants forced pregnant women they had sold into slavery to have abortions, according to three young Yazidis who escaped from the Islamic militants' brutal clutches.

After abducting hundreds of young women and girls from their homes in Iraq's Sinjar province last August, ISIS fighters rounded the captives up in "slave markets" where they were picked out to be used for sex.

The terror group was so intent on using rape as a weapon of war that they brought in their own doctors -- gynaecologists -- to determine which of the women they had captured were virgins.

Bushra, 21, says she witnessed two doctors invasively examine girls to find out if they were already pregnant. Those found to be expecting were forced to abort their babies.

"One of my friends was pregnant," Bushra recalls. "Her child was about three months in the womb. They took her into another room. There were two doctors and they did the abortion.

"Afterwards, they brought her back. I asked her what happened and how they did it. She said the doctors told her not to speak."

Bushra says the abortion left her friend bleeding heavily, and in so much pain that "she could not talk or walk."

Photos: Fleeing ISIS: Life for Yazidi child refugees Photos: Fleeing ISIS: Life for Yazidi child refugees The Sharia Camp in Dohuk, Iraq houses 18,575 people in 4000 tents. It opened in 2014 and includes four schools -- two Arabic, two Kurdish. Many residents have escaped from their home in Sinjar after ISIS invaded and captured many Yazidis. Three-year-old Farhad Naifg is from Sinjar. He has been living in the camp for a year.

Hide Caption 1 of 9 Photos: Fleeing ISIS: Life for Yazidi child refugees Two-year-old Basman Haidar and his grandfather Haidar Kharmish, have also spent a year in the camp.

Hide Caption 2 of 9 Photos: Fleeing ISIS: Life for Yazidi child refugees 9 year-old Katrine Hamou and her two-year-old brother Zimar Hamou are from Sinjar.

Hide Caption 3 of 9 Photos: Fleeing ISIS: Life for Yazidi child refugees Three-year-old Muna Rasho is from Sinjar. She came to the camp a year ago with her three brothers and two sisters.

Hide Caption 4 of 9 Photos: Fleeing ISIS: Life for Yazidi child refugees Marwa Khalil, who is eight years old, escaped from Sinjar with her family. She suffers from a skin disease and can't go to school because other children refuse to sit next to her.

Hide Caption 5 of 9 Photos: Fleeing ISIS: Life for Yazidi child refugees Miada Murad is eight years old, from Sinjar. She has five sisters. Hide Caption 6 of 9 Photos: Fleeing ISIS: Life for Yazidi child refugees Gawre Murad, 40, and her son Aryan, four, escaped from Sinjar a year ago.

Hide Caption 7 of 9 Photos: Fleeing ISIS: Life for Yazidi child refugees Shami Ravo Hussain, left, and Gozi Haji, right, fled when ISIS came to their village Siba Sheikh Khidir, near Sinjar. Hide Caption 8 of 9 Photos: Fleeing ISIS: Life for Yazidi child refugees Gule Rasho, 23, and her son Rami, 11 months, also escaped from Siba Shekh Khidir.

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"She was the first. After that, they took the pregnant women and put them in a separate house."

Noor, Munira and Bushra say they were abducted when fighters stormed their villages; separated from their families and spirited away to ISIS controlled regions of Iraq, they were forced into sex slavery.

The refugee camps of Dohuk are filled with stories like theirs, of women and girls bought and sold, given as gifts, or bartered for weapons.

Bushra says she was living a "normal ... interesting ... good life," until ISIS arrived in Sinjar and tore her away from everything she knew.

"They told us, 'Give up your family, give up that you are Yazidi -- you are now Muslims. We are going to marry you; each fighter will have one of you.'"

Lined up for "inspection," Munira, 16, says the militants examined the "belly, teeth, breasts" of her and the other captives before choosing who they wanted as a "wife."

"If the girl said, 'I don't want to come with you,' or 'I don't want to marry you, they would take [her] by force," remembers Noor, 22. "There was no other choice.

"One man picked me. He was old, ugly and fat. I was so scared. There were some other ISIS fighters so I begged one of them, 'Please, take me. Take me anywhere and marry me, if you want, but take me away from this one.' So he did."

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Noor says that while she wasn't forced to have sex with him immediately, two days later the fighter who had chosen her returned from the front line.

"He showed me a letter and said 'This shows any captured women will become Muslim if 10 ISIS fighters rape her.'"

She says he raped her, before giving her to his friends: "I was passed on to 11 others." Each one raped her, she says.

The Yazidis, a small Iraqi minority who believe in a single god who created the Earth and left it in the care of a peacock angel, have been subjected to large-scale persecution by ISIS, which accuses them of devil worship.

ISIS claims the Quran justifies taking non-Muslim women and girls captive, and permits their rape -- a claim vociferously denied by Islamic scholars.

Munira, whose arm bears a homemade tattoo of her father's name, inked into her skin with a sewing needle as she waited to be "sold," fidgets next to Noor as she tells CNN her story.

"I was given as a prize to another ISIS fighter. Twice," she says. "The second time, I was traded for another girl."

Traumatized by everything she had seen, Bushra found a bottle of pills and swallowed them all, hoping to end her life rather than become a victim of rape , but she survived.

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"I collapsed and didn't die," she says. "They took me to the hospital and in the hospital I woke up."

Once she recovered from the suicide attempt, she too was raped.

She was not the only one to try to kill herself -- the women say they knew others who succeeded in taking their own lives, but that their captors were determined to keep them alive if they could.

"One day, there were 14 girls with me," says Bushra. "They tried to kill themselves by drinking rat poison, but [ISIS] took them to the hospital and cleaned their stomachs.

"They told us: 'We will not let you die so easy.'"

As hard as it may be to believe, Noor, Munira and Bushra (their names have been changed, to protect their identities) are the lucky ones: they escaped, and made it to the refugee camps.

Now safe, they have been bravely telling their story. They recently traveled to the UK with the AMAR Foundation , to warn British schoolchildren of the dangers posed by radicalization.

The three women have been offered asylum in the West and will be relocating to start new lives overseas soon.

But hundreds more Yazidi women remain enslaved. The trio say they want to reveal the truth about ISIS and, they hope, to help those they left behind.