Jamieson, Fausset and Brown on Jeremiah 30:6

6. Ask--Consult all the authorities, men or books, you can, you will not find an instance. Yet in that coming day men will be seen with their hands pressed on their loins, as women do to repress their pangs. God will drive men through pain to gestures more fitting a woman than a man (Jr 4:31; 6:24). The metaphor is often used to express the previous pain followed by the sudden deliverance of Israel, as in the case of a woman in childbirth (Is 66:7-9).

paleness--properly the color of herbs blasted and fading: the green paleness of one in jaundice: the sickly paleness of terror.