MTV has renewed “Teen Mom” for a fourth season, two months before the newly announced third-season premiere date of July 5.

Teen Mom” is the No. 2 original cable series in the 12-34 demo behind MTV’s “Jersey Shore” and, like that unscripted skein, is growing rapidly in audience. The second season of “Teen Mom” delivered a 56% increase in the demo, making it No. 1 in all of cable on Tuesdays, and reached an average of 3.8 million viewers per week.

Morgan J. Freeeman exec produces. MTV also said that, beginning Wednesday, members of the show will be featured in a series of candid public service announcements concerning sex and preventing teen pregnancy.