Reference for Niddah 72:3

דברי רבי אליעזר

SHE WAS RELIEVED FROM HER PAINS FOR TWENTY-FOUR HOURS AND THEN GAVE BIRTH, SHE IS REGARDED AS HAVING GIVEN BIRTH IN A <i>ZIBAH</i>;<span class="x" onmousemove="('comment',' As the pains ceased before birth it is evident that the previous discharge (cf. prev. n. but one) was not due to the labour but to zibah. Had the pains continued until birth all the previous bleeding would have been attributed to that of the labour which is Pentateuchally clean. ');">³</span>

Jastrow