Terror Within  (1977)
New Concorde

In the grueling aftermath of a chemically-induced plague that wipes out most of the world, the only survivors are a small group of scientists trapped in a laboratory 500 feet below the ground in the Mojave Desert. But they are not alone. George Kennedy stars a Hal, leader of the group. Andrews Stevens plays David the young hotshot who rescues a lone woman survivor only to make a shocking discovery: she's pregnant, she's due---and it's not human!