Um Haleema was just 16 years old when she was kidnapped. Her first few months in captivity, at the hands of militant group Boko Haram, were enough to break anyone's spirit -- let alone that of a teenage girl so far from home.

She was captured trying to escape, along with three of her friends, as Boko Haram burned and ransacked her village.

During her captivity, Um Haleema was forced to watch men, women and children slaughtered. She was forced into marriage. Forced to wait on a "husband" she hated. But while she watched, she says she was also waiting -- for a chance to break free. And after six long months, it finally came.

"I had planned my escape from the beginning," she says. "There was a time my husband spent two weeks away, so I attempted to escape but guards returned me and beat me."

Eventually, her captors' vigilance began to slip and she managed to escape. In her fear, all she remembers is walking for what felt like days until she finally reached safety.

She arrived home to discover that her father had been killed by the same Boko Haram militants who had held her captive for almost a year. She also found she had become pregnant by her Boko Haram husband.

Now, seven months along in her pregnancy, she has agreed to speak to CNN on the condition that we conceal her identity and change her name. She doesn't want to become the face of a growing crisis -- girls and women brutally victimized by Boko Haram.

The fear, she says, is still with her. This time, though, it's the men in her own community she is scared of.

"People in this village are rejecting me because of the pregnancy," she says. "Some will be happy to have me dead. Many people are even saying that I should go for an abortion."

It's an option she refuses to contemplate, even though she says local men have let it be known they will not tolerate the children of Boko Haram living amongst them. She says they have threatened to kill both her and her baby.

There are no exact figures, but aid agencies and government officials have told CNN that an alarming percentage of girls rescued from Boko Haram have returned pregnant.

The UNFPA, which is working in camps for Nigeria's internally displaced, reports that 214 women in the camps are visibly pregnant, but it is still assessing how many got pregnant while being held by Boko Haram, and if there are still more in the earlier stages of pregnancy.

"We do not know yet the total number of pregnant girls among those rescued," said Stephane Dujarric, spokesman for United Nations Secretary-General Ban Ki-moon in a report. "The screening is still ongoing." UNFPA said it is working to meet the medical, physical and psychological needs of the freed women.

In recent months, Nigeria's military has raided several Boko Haram bases freeing captive women and children. In late April to early May, about 700 women and girls were rescued in separate operations.

On hearing that her daughter had been abducted, Um Haleema's mother says she immediately feared the worst.

"Anybody captured by Boko Haram is presumed dead," she explains. "They abducted my step-daughter‎ and my daughter. They took a total of seven girls from this house."

She says she has heard of many mothers who felt that abortion was the only option they had, but insists it's not a risk she's willing to take with her daughter.

"We heard about one girl who died after she attempted an abortion, losing both the mother and the baby," she says. "The girl was the only child to her mother, so that scared us. If God wishes, she will give birth safely. Life is in the hands of God alone."

Boko Haram: A bloody insurgency, a growing challenge

CNN spoke to the men Um Haleema accused of threatening her in her village. Part of a local vigilante group, they denied making the threats.

The vigilante groups in the north of Nigeria -- men who take up arms to protect their communities from Boko Haram -- have long been used by the Nigerian government in an auxiliary capacity to fight against the militants. Their leader agreed to speak CNN.

"I am not aware of any woman in this village who was impregnated by them," he said. "If any woman is found to be pregnant, in our tradition, the pregnancy is considered Haram (unlawful), hence we cannot accept them wholeheartedly because they can be like baby snakes."

In Muslim communities, pregnancy outside of marriage is often seen as illegitimate, unless the mother can prove it was against her will.

When the interview ended and the camera stopped rolling, the vigilante leader said that his group didn't believe Um Haleema had been forced into marriage and said that she and her unborn child will always be viewed with suspicion. But he refused to comment on what he and his men might do about it.

Regardless of what others say, surviving both abduction and escape has made Um Haleema realize that she has the strength to see this through. Her child, she says, deserves to live.