Albert Barnes Commentary Psalms 48:6

"Trembling took hold of them there, Pain, as of a woman in travail." — Psalms 48:6 (ASV)

Fear took hold upon them there - Trembling seized them; they were filled with sudden consternation. That is, as soon as they saw the city, or had a distinct view of it, they became alarmed.

And pain - Distress; anguish. The distress arising from disappointed hopes, and perhaps from the apprehension of their own safety. They were filled with dismay.

As of a woman in travail - This comparison is often used in the Scriptures to denote the severest kind of pain. (Jeremiah 6:24; Jeremiah 13:21; Jeremiah 22:23; Jeremiah 30:6; Jeremiah 49:24; Micah 4:9–10; Isaiah 53:11).