What does fortune-telling Jade Swallow mean?

Yu Yan threw herself at her, and the story was named. Wang Renyu's "The Legacy of the Dream of Heaven and Treasure in Kaiyuan" was published in the Five Dynasties. Zhang's mother, the prime minister of the Tang Dynasty, once dreamed that a jade swallow was thrown into her arms. Later, she became pregnant and gave birth to Zhang. Later, he used "Yu Yan threw herself at her" as a eulogy to congratulate her life.

The fortune teller said that you are pregnant with jade, which means that you can achieve great things after giving birth.