This is called a decidual cast. It occurs when the lining of a woman's uterus sheds as one massive solid piece of tissue during her period. : r/MakeMeSuffer

Decidual Cast: What Is It, Symptoms, and When to Seek Help

Everything You Need to Know About a Decidual Cast

Everything You Need to Know About a Decidual Cast

Non-Painful Out of Pill Membranous Dysmenorrhoea

What is a decidual cast? See photos and learn the cause behind it

Is it normal to pass solid pieces of uterine lining during

Non-Painful Out of Pill Membranous Dysmenorrhoea

What is a decidual cast? See photos and learn the cause behind it

This Nurse's TikTok About Passing a Decidual Cast During Her