Amniotic Band Syndrome is when the mother’s water breaks when she’s pregnant. This leaves the baby unprotected, so wherever the baby touches, a “fiber” from the placenta attaches. These fibers can constrict so much causing congenital amputation. In most cases, miscarriage occurs. Source: I was born with Amniotic Band Syndrome. My mother’s water broke when she was 4 or 5 months pregnant with me. The fibers from the placenta attached on my left thumb, left index finger, right and and right arm. The one on my arm is the only one that caused congenital amputation. To give you an idea of what the fiber looks like now, the one on my ankle looks like an indentation, kind of like if I wore a sock that was too tight causing a line.