The birth pangs will be seen in the final hours of earth's existence, just prior to the second coming of Jesus Christ in fire and Final judgement.
Isaiah 66:5-15KJV
5 Hear the word of the Lord, ye that tremble at his word; Your brethren that hated you, that cast you out for my name's sake, said, Let the Lord be glorified: but he shall appear to your joy, and they shall be ashamed.
6 A voice of noise from the city, a voice from the temple, a voice of the Lord that rendereth recompence to his enemies.
7 Before she travailed, she brought forth; before her pain came, she was delivered of a man child.
8 Who hath heard such a thing? who hath seen such things? Shall the earth be made to bring forth in one day? or shall a nation be born at once? for as soon as Zion travailed, she brought forth her children.
9 Shall I bring to the birth, and not cause to bring forth? saith the Lord: shall I cause to bring forth, and shut the womb? saith thy God.
10 Rejoice ye with Jerusalem, and be glad with her, all ye that love her: rejoice for joy with her, all ye that mourn for her:
11 That ye may suck, and be satisfied with the breasts of her consolations; that ye may milk out, and be delighted with the abundance of her glory.
12 For thus saith the Lord, Behold, I will extend peace to her like a river, and the glory of the Gentiles like a flowing stream: then shall ye suck, ye shall be borne upon her sides, and be dandled upon her knees.
13 As one whom his mother comforteth, so will I comfort you; and ye shall be comforted in Jerusalem.
14 And when ye see this, your heart shall rejoice, and your bones shall flourish like an herb: and the hand of the Lord shall be known toward his servants, and his indignation toward his enemies.
15 For, behold, the Lord will come with fire, and with his chariots like a whirlwind, to render his anger with fury, and his rebuke with flames of fire.
