Dream of elephants are said to be premonitions of attaining power, or spiritual gains.  Maya devi the mother of Gouthama Buddha was said to have had a dream of a seven tusked elephant piercing her womb before she gave birth to the Buddha.  It might have been a fancy way of saying that she had a premonition of the arrival of a great one, but I feel that from the perspective of Maya devi, or any women it would not be a good premonition.  She immediately died after the birth and could no longer be a part of the world of her child, guiding and showing him  a world perspective only she sees.