How Long Is “Terror Within”?

This sci-fi horror film is a knock-off of the Alien films. Set in the Mojave desert in the 21st century, it depicts a desolate world that has been ravaged by a human engineered plague virus where the few people live underground and the surface is populated by strange monsters. Unfortunately, for the humans below, food must be gathered on the surface. David is up on a foraging mission when he finds a pregnant woman and brings her down to his medical center. Unfortunately, she has been impregnated by one of the creatures and its offspring bursts from its womb in a gory spray of blood and guts. It's a hungry little thing and as it grows, devours every human in its path except for David and a physician. In addition to seeking nourishment, the creature is looking for human women to breed with.