![1girl absurdres blush collared_shirt commentary_request durandal_(kei) grey_background grin head_tilt heart heart-shaped_pupils highres holding idolmaster idolmaster_cinderella_girls jewelry limited_palette long_hair monochrome necklace necktie partial_commentary pregnancy_test shibuya_rin shirt simple_background smile solo symbol-shaped_pupils rating:s score:14 post #3639769](/cdn_image/preview/c7/4e/c74e3a19ce88ccebaa2ea29cb72bcbd7.jpg)
A small stick-like object used to determine whether or not a woman is pregnant, determined by matching (usually) pink lines after a urine sample.
In what tends to be uploaded to Danbooru, they're meant as a joke about unprotected sex and/or pregnancies unwanted by at least one of the involved parties.
A minor meme related to pregnancy tests cropped up in late 2014, where a feminine finger pointing to a pregnancy test would be added into existing images. (See post #1824996 and its parent.)
Do not add the pregnant tag unless the character has a visibly pregnant belly.