NET
16 Your eyes saw me when I was inside the womb. All the days ordained for me were recorded in your scroll before one of them came into existence.
Darby
16 Thine eyes did see my unformed substance, and in thy book all [my members] were written; [during many] days were they fashioned, when [as yet] there was none of them.
KJV
16 Thine eyes did see my substance, yet being unperfect; and in thy book all [my members] were written, [which] in continuance were fashioned, when [as yet there was] none of them.