Preterm pregnancies

Brianna • 23. Student & mamabear to two handsome boys♡
My first was born 6 weeks early. Fortunately he was healthy as could be, but there never was any answers as to why I went into preterm labor.. I'm now expecting #2 and concerned that it will happen again. Did any of you have preterm 1st babies, and fullterm 2nd babies?! I'd love to be able to keep this one cooking for as long as I can!! TIA!