If I have had a previous preterm birth, does that mean I will have another one?

Increased risk. Your risk is higher than normal. Depending on the circumstances of the previous birth, you should ask your doctor about Progesterone injections to help decrease your risk.
Depends on the reaso. Reason , but it means u are more at risk for one but you should be watched closely and your OB or peri- natologist will be checking your cervical length closely and monitoring u cause now you can get on im progesterone- fda approved to prevent premature labor, but speak with your OB before u get preg so u can get an idea of the plan.