Q: What are the odds of preterm delivery?

A: The odds of preterm birth are:

1. No prior birth, no risk factors: 7-8% risk
2. Two prior births, both not preterm: 2.6% risk
3. One prior birth, not preterm: 4.4% risk
4. Two prior births, first preterm, second term: 5.7% risk
5. One prior preterm birth: 17.2% risk
6. Two prior births, both preterm: 28.4% risk