You've probably seen it everywhere, but in case you're unawares, here's the gist of it from Know Your Meme:
Pregnancy Announcement, also known as "Pregnancy Test" (Japanese: 妊娠検査薬) or "Pregnancy Collage" (妊娠コラ), refers to a photoshop meme based on an exploitable image of a pregnancy test strip indicating a positive result, which can be superimposed over various illustrations of fictional anime characters. The meme began circulating on Twitter on October 2014.