"So far so good," she captioned the black-and-white mirror selfie. "Apparently I've swallowed a bell pepper this week..." According to a few websites, a fetus 18 weeks along is comparable to the size of a bell pepper, which may explain her reference to the vegetable.
She re-posted it in collage form, however, simply captioning it with a baby emoji the second time around.
Earlier this month, Levine, 37, made his first public statement that his wife was pregnant. He shared a sweet snap of her posing in a bikini (the same one she wore in her latest pic!) and a Los Angeles Lakers cap while relaxing by the pool via Instagram.
"My two favorite Laker fans," the Maroon 5 frontman wrote, with baby, milk bottle and basketball emojis.
A source confirmed the pregnancy to ET on March 10, adding that Prinsloo was 12 weeks along at the time and knows the sex of the baby. Though the couple has yet to officially confirm the baby's gender, a source tells ET that it is their understanding that Prinsloo is having a girl, as she was recently spotted at Bel Bambini, an upscale baby boutique in West Hollywood, California, looking at a few pink items.
To hear more on the parents-to-be, watch the video below.