Reference for Chullin 139:24
יצא רובו הרי זה יקבר
Raba raised these questions: What is the law if one wrapped it up<span class="x" onmousemove="('comment',' The foetus was wrapped up in one of these articles and was thus extracted from the womb of its dam but no part of the foetus came into direct contact with the womb. Now it is the womb that renders the firstling holy, for throughout the Torah the firstling is described as that which 'openeth the womb' (e.g., Ex. XIII, 2) . The question raised by Raba is this: must there be actual contact between the foetus and the womb when the foetus is being delivered, and otherwise it would not be regarded holy as a firstling, or is it sufficient that it passes through the womb although it makes no direct contact?');"><sup>11</sup></span>