Is there a chiastic structure in Revelation chapter 12? Some scholars support the idea, but others dismiss the theory. David A. deSilva criticized authors who proposed chiastic structures on flimsy ground, and for “(1) developing chiastic outlines by means of selective shaping of summary statements for major blocks of text; (2) discovering a chiasmus by means of selective reading of key terms; and (3) creation of a chiasmus by means of manipulation of formal markers.” 
Recognizing a chiasmus, where it really exists, aids interpretation, as it offers an alternative to the view that says the prophecies are to be understood chronologically. In a chiastic structure, a sentence in the final section may illuminate a previous related statement.
William H. Shea proposed the following chiastic structure for Revelation 12, as Figure 1 in his article. 
A 12:1-5 woman & man child B 12:6 woman in wilderness 1,260 days C 12:7-9 war in heaven, Michael vs. dragon D 12:10-11 inaugration of salvation at cross / appropriation of salvation by Lamb's blood C' 12:12 dragon cast down / heaven delivered, but woe to earth B' 12:13-16 woman in wilderness 3½ times A' 12:17 woman & her seed
The same article included an alternative, more detailed chiastic interpretation.
A 12:1-2 B 12:3-4a C 12:4b-5 D 12:6 E 12:7-9 F 12:10 F' 12:11 E' 12:12 D' 12:13-14 C' 12:15-16 B' 12:17 A' 13:1
In another article, Shea presented a different chiasmic scheme spanning Revelation 11:19-15:8, which appears to be somewhat contradictory to those shown above. He noted a similarity between Rev. 12:17 and Rev. 14:12, both of which mention the Commandments, and the faith of Jesus, or the testimony of Jesus, and he suggested a chiasmus might explain the repetition. 
The most obvious evidence for chiastic structure in Revelation 12 is the repetition of the woman fleeing to the wilderness, in verses 6 and 14. The two accounts of the woman’s sojourn in the wilderness correspond in the several ways: they involve same woman; they have the same duration, 1,260 days, or “a time, times and a half;” the woman is nourished in each case; the wilderness is the same; her place is prepared by God.
These accounts of the woman’s sojourn in the wilderness differ in at least two ways:
Exodus 19:4 says that God bore the Israelites upon eagle’s wings. Isaiah speaks of eagles’ wings in connection with a renewal of strength:
But they that wait upon the LORD shall renew their strength; they shall mount up with wings as eagles; they shall run, and not be weary; and they shall walk, and not faint.
The “time, times and a half” links the woman fleeing to the wilderness to Daniel 7:25. The two wings of an eagle given to the woman represent a divine viewpoint. The human point of view, from ground level, is suggested by the “eyes like the eyes of a man” of the little horn in Daniel 7. The spiritual viewpoint is enlightened by God, and the gospel, and is not literalistic. An eagle soars at a great height, viewing the earth from above, suggesting an higher, divine point of view. Isaiah said God’s thoughts are higher than man’s:
Seek ye the LORD while he may be found, call ye upon him while he is near:
Let the wicked forsake his way, and the unrighteous man his thoughts: and let him return unto the LORD, and he will have mercy upon him; and to our God, for he will abundantly pardon.
For my thoughts are not your thoughts, neither are your ways my ways, saith the LORD.
For as the heavens are higher than the earth, so are my ways higher than your ways, and my thoughts than your thoughts.
In Revelation 12, John must have had a reason for describing the woman fleeing to the wilderness twice, other than literary style. The first and second flights of the woman to the wilderness are contrasted below.
In her first flight to the wilderness, there is a famine of “hearing the word of the Lord.” [Amos 8:11-13]
In her first flight to the wilderness, there is no rain of the word of God, but a famine. The 1,260 days correspond to the three and a half years of no rain in the days of Elijah. The two witnesses have power to “shut heaven.” [Revelation 11:6] The “rain” is symbolic of God’s word.
In her first flight to the wilderness, the holy city is trampled by Gentiles. [Revelation 11:2] People view the prophecies through the spectacles of men who they view as spiritual “giants,” and see themselves as “grasshoppers” in comparison to them. They quote from commentaries, and follow the traditions of men that are embraced by particular denominations or sects, that effectively kill the two witnesses, the word, and the Spirit.
In her first flight to the wilderness, the saints are overcome by the little horn, the Antichrist spirit. [Daniel 7:21, 25]
In her first flight to the wilderness, the saints are scattered. [Daniel 12:7] This has been fulfilled, and is shown by the tens of thousands of denominations.
In her first flight to the wilderness, the church becomes desolate, like a valley of dry bones. [Ezekiel 37:1-2]
In her first flight to the wilderness, the church is plundered by the armies of Gog and Magog. [Ezekiel 38:10-13]
In Zechariah’s prophecy, in Zechariah 14:1-3, many of the saints are taken into captivity, houses rifled, and women ravished. It is a spiritual seduction, such as Paul alludes to in 2 Corinthians 11:1-3.
In her first flight to the wilderness, the world rejoices over the desolation of the church, and the death of the two witnesses. [Revelation 11:10]
In her second flight to the wilderness, the saints have renewed strength. The woman has been given eagle’s wings. [Revelation 12:14] Through the enlightenment of prophecy, she views things “from above,” as pictured by eagle’s wings, whereas in the first flight to the wilderness, her point of view was earth-bound, having “eyes like the eyes of a man.”
And to the woman were given two wings of a great eagle, that she might fly into the wilderness, into her place, where she is nourished for a time, and times, and half a time, from the face of the serpent.
In her second flight to the wilderness, Satan, the accuser of the brethren, has been cast out. [Revelation 12:9]
In her woman’s second flight to the wilderness, the wilderness itself is changed. Isaiah said, the wilderness will be glad; the desert will “blossom as the rose;” [Isaiah 35:1] streams will flow in the desert; [Isaiah 35:6] the mountains and hills bring forth fruit; [Ezekiel 36:11] hills will rejoice. [Psalm 65:11-13] God will make bright clouds, and showers of rain. [Zechariah 10:1]
In her second flight to the wilderness, the woman has some help; the flood from the serpent’s mouth gets swallowed up by the earth. [Revelation 12:16] The “land” that swallows up the flood is symbolic of spiritual things promised to the saints. One of these is the promise that the Spirit will guide the church to the truth. This is what swallows up the serpent’s flood. His deceptions are exposed.
In the woman’s second flight to the wilderness, the two witnesses come to life, and stand on their feet. [Revelation 11:11]
Daniel said the beast is slain, and his body given to the burning flame. [Daniel 7:11]
The fire of God’s word falls upon those who “know not God.” [2 Thessalonians 1:7-8]
In the woman’s second flight to the wilderness, the war between the angels has been fought. The saints are victorious. [Revelation 12:11-12]
In the woman’s second flight to the wilderness, the ark of the covenant is seen in the temple. [Revelation 11:19] This may be understood as the fulfillment of the new covenant, that says God will write his laws on our hearts, and remembers our sins no more. [Hebrews 10:16-17]
The following chiastic structure is proposed:
A woman clothed with the sun [v. 1] B woman with child [v. 2-5] C dragon seeks to devour her child [v. 4b-5] D woman fled to the wilderness [v. 6] E war in heaven [v. 7] F Satan cast out, deceives the whole world [v. 9] G the saints overcome by the blood of the Lamb [v. 11] F' rejoicing in heaven, woe in earth [v. 12] E' dragon persecutes the woman [v. 13] D' woman fled to the wilderness [v. 14] C' flood threatens woman, and the earth swallows up the serpent's flood [v. 15-16] B' woman's seed [v. 17] A' saints keep the commandments [v. 17]
John had reasons to write the prophecy of Revelation 12 in the form of a chiasmus. Shea pointed out that the dragon seeking to “devour her child as soon as it was born” of verse 4 corresponds to the earth opening her mouth, and swallowing up the flood from the mouth of the dragon in verse 16, the C-C’ pair above.
The sun which clothes the woman in verse 1 is paired with the saints keeping the commandments, and having the testimony of Jesus Christ, in verse 17. This fits, because the sun represents the gospel; and keeping the commandments, and having the testimony of Jesus Christ, is what the gospel means. Jesus said, when the tares are removed from among the wheat, in the parable of the tares, “Then shall the righteous shine forth as the sun in the kingdom of their Father. Who hath ears to hear, let him hear.” [Matthew 13:43]
1. David A. deSilva. X Marks the Spot? A Critique of the Use of Chiasmus in Macro-Structural Analyses of Revelation. Journal for the Study of the New Testament March 2008. vol. 30, no. 3, 343-371.
2. William H. Shea. The chiastic structure of Revelation 12:1-15:4 the Great Controversy vision. Andrews University Studies, Autumn 2000, Vol. 38, No. 2, 269-292.
3. William H. Shea. The Controversy Over the Commandments In the Central Chiasm of Revelation. Journal of the Adventist Theological Society, 11/1-2 (2000): 216-231.