We appreciate and encourage your need to support your wife during childbirth, and through the earlier stages you can aid her in any way as long as she does not experience uterine bleeding.
Even if your wife does not bleed during labor, she will become a niddah when her cervix is dilated during the final stages of labor. She is not halachically required to undergo an internal examination to determine the degree of dilation. From the point she becomes a niddah, you are subject to all the the harchakot.
If a woman’s cervix is dilated by a few centimeters early in labor (or earlier in her pregnancy), but she has not had any bleeding, she does not yet become a niddah.
When you are no longer able to have physical contact, we are certain that the encouragement you can offer verbally and just be being there in the room with her will be extremely significant. Be sure you are standing in a place where you cannot view the actual delivery, near the head of the bed or behind a curtain.
If the wife is in great emotional distress during contractions, the husband may assist in any way necessary, since that is considered pikuach nefesh (a life saving action).
Please see our articles on Childbirth for a more detailed discussion of this topic.
We wish your wife a healthy and easy delivery, Besha’ah Tovah