Uttara is one of the characters in Mahabharata who portrays surrender unto the supreme personality of godhead Sri Krishna. She was the wife of Abhimanyu and the mother of Maharaj Parikshit, the grandson of Pandavas.
Uttara was the daughter in law of Arjuna, the dear devotee friend of Lord Sri Hari, who appeared in his original form in the Dwapara Yuga in order to protect his dear devotees and crush the miscreants.
Ashwattthama had already killed all the sons of Pandavas using his brahmastra, the lethal nuclear weapon surcharged with power of devastating mantras. When he saw that the lineage of pandavas is still there in the womb of arjuna’s daughter in law, he decided to finish the progeny by releasing the brahmastra towards Uttara to the child in her womb.
She immediately approached lord Krishna and spoke as follows (From Bhagwatam)
SB 1.8.8— As soon as He seated Himself on the chariot to start for Dvārakā, He saw Uttarā hurrying toward Him in fear.
SB 1.8.9— Uttarā said: O Lord of lords, Lord of the universe! You are the greatest of mystics. Please protect me, protect me, for there is no one else who can save me from the clutches of death in this world of duality.
SB 1.8.10— O my Lord, You are all-powerful. A fiery iron arrow is coming towards me fast. My Lord, let it burn me personally, if You so desire, but please do not let it burn and abort my embryo. Please do me this favor, my Lord.
SB 1.8.11— Sūta Gosvāmī said: Having patiently heard her words, Lord Śrī Kṛṣṇa, who is always very affectionate to His devotees, could at once understand that Aśvatthāmā, the son of Droṇācārya, had thrown the brahmāstra to finish the last life in the Pāṇḍava family.
SB 1.8.12— O foremost among the great thinkers [munis] [Śaunaka], seeing the glaring brahmāstra proceeding towards them, the Pāṇḍavas took up their five respective weapons.
SB 1.8.13— The almighty Personality of Godhead, Śrī Kṛṣṇa, having observed that a great danger was befalling His unalloyed devotees, who were fully surrendered souls, at once took up His Sudarśana disc to protect them.
SB 1.8.14— The Lord of supreme mysticism, Śrī Kṛṣṇa, resides within everyone’s heart as the Paramātmā. As such, just to protect the progeny of the Kuru dynasty, He covered the embryo of Uttarā by His personal energy.
SB 1.8.15— O Śaunaka, glory of Bhṛgu’s family, although the supreme brahmāstra weapon released by Aśvatthāmā was irresistible and without check or counteraction, it was neutralized and foiled when confronted by the strength of Viṣṇu [Lord Kṛṣṇa].
SB 1.8.16— O brāhmaṇas, do not think this to be especially wonderful in the activities of the mysterious and infallible Personality of Godhead. By His own transcendental energy He creates, maintains and annihilates all material things, although He Himself is unborn.
SB 1.8.17— Thus saved from the radiation of the brahmāstra, Kuntī, the chaste devotee of the Lord, and her five sons and Draupadī addressed Lord Kṛṣṇa as He started for home.
Thus, she was protected by the Lord and in due time, Maharaj Parikshit was born.