As Lois (Amy Adams) reaches into her bedside table drawer for her press credentials, underneath is a Force Majeure pregnancy test. Zack makes a point to show it twice. Not knowing what force majeure meant I looked it up:
force majeure (French)
1. superior or irresistible force
2. an event or effect that cannot be reasonably anticipated or controlled; act of God
The test refers to the fact that intercourse with Superman is an irresistible force and it took an act of God for her to survive it, much less get pregnant.