Girls whose friends have experienced teen childbirth are less likely to get pregnant themselves, a new study suggests.

The researchers compared two groups of teen girls: those with a similarly-aged friend who'd given birth, and those with a friend who'd had an early miscarriage.

They wanted to see whether these events affected the girls' choices in having sex, getting pregnant, having a child, and getting married as teens - or their choices regarding school, marriage and family as adults.

Altogether, the investigators studied 595 young women from across the U.S., interviewing them multiple times over the years, starting in 1994-1995 when they were in their early teens.

Compared to girls whose friends had miscarried, those whose friends became teen mothers were less likely to have sex as teens, get pregnant or get married and more likely to attain their college degree.

"Teens learn from their friends' mistakes," study co-author Dr. Olga Yakusheva of the University of Michigan in Ann Arbor told Reuters Health by phone.

"It's common sense, really - we obviously know few people would follow their friends jumping off the proverbial cliff, but that's how we used to think about peer influences among teens," she said

But the study, published June 16 in the Journal of Adolescent Health, suggests that teens learn from their friends' mistakes.

Furthermore, girls in the teen birth group were 5 percentage points less likely to have a baby themselves as a teen, compared to those in the miscarriage group.

"Sixteen of every 100 girls whose friend had a miscarriage had a teen childbirth themselves, whereas in (girls whose friends had babies) group, the number was lower, with only 11 girls having a teen birth," Yakusheva said.

In 2000-2001 - the fifth year after the start of the study - girls whose friends had given birth had about 25 fewer sexual intercourse encounters, on average, than girls whose friends had miscarried.

Odds of getting married before age 20 were about 6 percentage points lower for the teen birth group versus the miscarriage group. Moreover, women in the teen birth group were 8 percent more likely to complete a four-year degree.

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No long-term effects were found in income earnings, possibly because the college-educated women in the study were just starting out in their career, the study authors write.

Stigma might be one reason why the teens who were friends with a teen mom chose not to get pregnant, said Jane Champion of the University of Texas at Austin, who was not involved with the study.

Pregnant teens often drop out of school or go to alternative schools, which can have an impact on their social lives, said Champion, who specializes in behavioral intervention in teen pregnancy.

"They're often ostracized by their community and no longer accepted by their circle of friends," she said. "That can be a huge wake up call for teens."

Preventing early teen pregnancies is what matters, Yakusheva noted.

"What our work shows is that, in addition to teaching kids how not to become pregnant, we should also teach them why," she said.

She recommends exposing teens to the realities of pregnancy.

"Kids have to see it for themselves," she said, "not read it in books, not have an adult tell them, because that's already being done and it doesn't work very well."