there is an ayat that prohibits that: 4:119 : http://quran.com/4/116-122 :
They call upon instead of Him none but female [deities], and they [actually] call upon none but a rebellious Satan. Whom Allah has cursed. For he had said, "I will surely take from among Your servants a specific portion. And I will mislead them, and I will arouse in them [sinful] desires, and I will command them so they will slit the ears of cattle, and I will command them so they will change the creation of Allah ." And whoever takes Satan as an ally instead of Allah has certainly sustained a clear loss.
i think if quran contradicts hadith, quran wins. so, there is hadith, shown in answer of mujahid, that shows that prophet said nothing to disallow piercing while dealed with usage of earrings, but, i think, it should not be used to think that it is ok to pierce body, because, as you see, allah said that it is idea given by satan. i think, maybe, they, the women, in time of muhammad, refuced to pierce their daughters and used only already made holes in ears, maybe, they attached earrings somehow without piercing. another story, about abu zar, http://sunnah.com/search/?q=eleven+women , also can be interpreted so it is not used to allow piercing. (maybe it was so clear to everybody from quran that piercing is bad, that muhammad did not say about that, as the main topic of story and of muhammad's answer is another, not about piercing).