Jamieson, Fausset and Brown on Revelation 12:2

2. pained--Greek, "tormented" (basanizomene). De Burgh explains this of the bringing in of the first-begotten into the world AGAIN, when Israel shall at last welcome Him, and when "the man-child shall rule all nations with the rod of iron." But there is a plain contrast between the painful travailing of the woman here, and Christ's second coming to the Jewish Church, the believing remnant of Israel, "Before she travailed she brought forth ... a MAN-CHILD," that is, almost without travail-pangs, she receives (at His second advent), as if born to her, Messiah and a numerous seed.