When Teen Mom 2 premieres next month, the popular reality series chronicling the lives of teen moms Kailyn Lowry, Leah Messer, Chelsea Houska and Jenelle Evans will get a whole lot more interesting.

As a just-released season preview trailer shows, the foursome face uphill battles as they parent their toddlers while dealing with angry ex-boyfriends and husbands.

When Messer's story resumes, she and ex Corey Simms -- who wed in 2010 only to split six months later -- struggle with their 2-year-old twin daughter Ali's latest medical crises. In one scene above, Messer dissolves into tears as the little girl undergoes a brain MRI to help diagnose her developmental delays. Later, Simms fumes when he finds out Messer cheated on him -- again -- before she filed for divorce.

Also in the clip above, viewers find out Houska's issues with her slacker ex, Adam Lind, are far from over. Though details are scarce, Houska reveals that Lind angrily took their daughter, Aubree, 2, from her mother's care.

For more of what to expect from this season of Teen Mom 2 -- including Lowry's battle with her ex, Jo and Evans' new legal woes -- watch the trailer above before the show's December 6 premiere.