text: if you had one preterm baby how long do you wait to have another baby?   it depends on the reason for having the preterm birth. was it something herditary? was it something you done (by accident) such as lifting something, sitting for long periods etc.? was it due to an incompetent cervix? anyway if it is a medical reason why your baby was born early you and you want to get to pregnant again you need to start seeing you ob now. there are things that can be done to prevent  this on future pregnancies.