En Caul Birth One of the Rarest & Most Sacred Ways to Be Born An en caul birth happens when a baby is born still completely inside the intact amniotic sac, appearing as if they are floating in a water-filled bubble. It’s often called a “mermaid birth” or “veiled birth” because of how ethereal and otherworldly it looks. 📊 How rare is it? True, fully intact en caul births are estimated to happen in only 1 out of every 80,000 births. Partial caul births (when part of the sac remains over the face)