Gokainin!!

"I'm...pregnant." Sawa, who works as a graphic designer at an advertising agency, discovers one morning that she's got a bun in the oven. Only one person could be the father, and it's her handsome, but strict supervisor at work, Director Ishiki. The incident happened a few months ago when she was celebrating a job well down with him after a huge project they worked on together. Perhaps they were feeling a bit too relaxed, but once a few drinks hit, they ended up sharing a kiss. The unexpected soft and gentle smooch with her drill sergeant of a supervisor leads to them spending the night together... However, it was only a one-time thing and they were never an item, so Sawa wavers about whether or not to tell him that she's pregnant. A romance that blossoms from an unexpected pregnancy is about to unfold!

(Source: Starts Shuppan)