A.T. Robertson Commentary Revelation 12:2

"and she was the child; and she crieth out, travailing in birth, and in pain to be delivered." — Revelation 12:2 (ASV)

And she was with child (κα εν γαστρ εχουσα). Perhaps εστιν to be supplied or the participle used as a finite verb as in 10:2. This is the technical idiom for pregnancy as in Mt 1:18,23, etc.

Travailing in birth (ωδινουσα). Present active participle of ωδινω, old verb (from ωδιν birth-pangs 1 Thessalonians 5:3), in N.T. only here and Ga 4:27.

And in pain (κα βασανιζομενη). "And tormented" (present passive participle of βασανιζω, for which see already 9:5; 11:10), only here in N.T. in sense of childbirth.

To be delivered (τεκειν). Second aorist active infinitive of τικτω, to give birth, epexegetical use. Also in verse 4.