Prior to the events before entering Granvania, Mahiru met her cousin Itsuki on their high school rooftop and claimed to be pregnant. Even with the claim that there was no partner she slept with and had 24 tests just to provide evidence. During the transportation to Granvania, Mahiru, as the star maiden Virgo, she had her symbol appear on her cheek and shortly after, expell the impurities from the labyrinth they were transported too. When they left and met with Mana, Mana explained that the expelling of impurities was often mistaken for the sympoms of pregnancy, including morning sickness.

Morning sickness

Mahiru's 'morning sickness'