Thanks for the query.
Though preterm labor
may not run in families, as you had previous history of preterm labor there is some possibility in this pregnancy
So you better take sufficient bed rest
You can go for examinations like febronectin levels in blood, urine microscopy, vaginal swab examination etc.
You can go for tocolytics if your doctor recommends.
For more details:http://www.indiastudychannel.com/resources/144672-Preterm-labor-etiological-factors-pathology.aspx