Kay

“They shall not labor in vain,
or bear children for calamity…
The wolf and the lamb shall feed together,
the lion shall eat straw like the ox…” (Isaiah 65:23-25)

“Unto the woman he said, “I will greatly multiply thy sorrow and thy conception; in sorrow thou shalt bring forth children.”

The KJV actually comes closer to the original intent than many other translations. The word translated sorrow in the KJV and pain in the NIV is used only 3 times in the Bible and while pain is a possible meaning, it isn’t translated that way anywhere else. The KJV’s sorrow is the preferred use.

By the way, the second time the word pain appears in the NIV’s version (with pain you will give birth to children) it comes from a different Hebrew word, used 7 times in the Bible. But that one isn’t translated pain anywhere else either. Again, sorrow is preferred as in the KJV rendering. Both these words come from the Hebrew root atsab. It appears 17 times, ten of which are rendered grieve, and once again pain is never used.
Which begs the question: were the modern translators more influenced by their perceptions and/or personal experience concerning childbirth than by the intent of the Hebrew?