Tekashi 6ix9ine's Daughter, Baby Mama Involved In Car Crash, Rushed t

Tekashi 6ix9ine's baby mama and daughter were involved in a nasty car crash this past Easter ... one that sent them straight to the ER with some serious injuries.

Sources tell TMZ ... Sara Molina, the mother of Tekashi's 6-year-old daughter, Saraiyah, was in an Uber minivan on the expressway in New York City. Saraiyah and Sara's sister were in the car too.

Their driver suddenly got cut off, resulting in them getting rear-ended pretty badly ... we're told Saraiyah was scared and crying after the ordeal.

An ambulance was called and all 3 were taken to the hospital. Sara's sister got whiplash. Saraiyah had serious pain in her arm.

Sara might've gotten the worst of it ... in addition to getting whiplash, like her sister, she also got a concussion and is still in a lot of pain. Sara has been battling multiple sclerosis prior to the crash.

Tekashi tells TMZ ... he had no clue this even happened. As you know, he and Sara haven't been on good terms for some time. He says he's going to contact Saraiyah's grandma to clear things up.