It once came to pass that Vyāsadeva arrived hungry and thirsty at Dhṛtarāṣṭra’s palace. Gāndhārī attended to him conscientiously. Vyāsadeva was pleased with the girl and blessed her, “You shall soon have one hundred sons as powerful as your husband.” In due course of time Gāndhārī conceived. 
For two years she bore the embryo within her womb, becoming increasingly anxious. Then one day news reached her that Kuntī had given birth in the forest to a boy as effulgent as the morning sun. Out of frustration and anger at her own excessively long gestation, she struck violently at her womb. She then brought forth a hard mass of flesh that resembled an iron ball. As her nurses informed her of the stillbirth, she was afflicted by grief and thought of Vyāsadeva and his boon.
At once the sage appeared before her and said, “What have you done?”
Gāndhārī told him how she had become overwhelmed with envy and frustration when she had heard of Kuntī giving birth to Yudhiṣṭhira. With tears in her eyes she said, “I struck my womb and this lump of flesh came out. What then was the meaning of your boon?”
Vyāsadeva replied that his words could never prove false. He asked the servants to bring one hundred one pots filled with ghee. He then sprinkled cool water on the lump of flesh and it gradually divided in
to one hundred and one parts, each the size of a thumb. These were placed in the pots which were then sealed and placed in a concealed spot. Vyāsadeva instructed that the pots should be opened only after two more years had passed. He then departed for his lonely mountain ashram.
Exactly after the two years had elapsed the pots were opened one by one. From the first came a child who was named Duryodhana. At the moment he was brought out of the pot the sound of braying asses and screaming vultures was heard. Jackals howled and the wind blew fiercely. Without any apparent cause, fires sprang up all around the city and raged in all directions.
Source : Mahabharat – Krishna Dharma Das – https://www.vedabase.com/en/mbk/1/3
