You may hear some chinese girls saying “我今天不想上班，因为我大姨妈来了wǒ jīn tiān bù xiǎng shàng bān ，yīn wéi wǒ dà yí mā lái le ”？I dont want to go to work today, beacase my period is coming"
You must think"okay, your Auntie is visiting ! Say hi to your Auntie ! " but actually “大姨妈dà yí mā ” in Mandarin is a slang which means “period 月经yuè jīng ”， some chinese girls prefer to say “大姨妈” instead of “period”is because they don`t want to feel akward when they directly say "period" among friends, especially male friends.
Formal : 月经yuè jīng priod
Informal ： used during chatting "大姨妈dà yí mā" or “事 shì - thing”
How to say I`m on my period " 我来月经了wǒ lái yuè jīng le/ 我来大姨妈了wǒ lái dà yí mā le /我来事儿了wǒ lái shì er le 。
