Revelation 12:1-5 (RSV) And a great portent appeared in heaven, a woman clothed with the sun, with the moon under her feet, and on her head a crown of twelve stars; she was with child and she cried out in her pangs of birth, in anguish for delivery. And another portent appeared in heaven; behold, a great red dragon, with seven heads and ten horns, and seven diadems upon his heads. His tail swept down a third of the stars of heaven, and cast them to the earth. And the dragon stood before the woman who was about to bear a child, that he might devour her child when she brought it forth; she brought forth a male child, one who is to rule all the nations with a rod of iron, but her child was caught up to God and to his throne,
Most Catholic commentators hold to a “dual application” of Revelation 12: i.e., Mary and the Church. This is a not-uncommon motif in interpretation of prophecy in Scripture. Thus, it’s no problem if someone applies several portions of the passage to the Church; we only object to the blanket denial that it also references the Blessed Virgin Mary. The following are some of the considerations for why we believe that it does apply at least partially to Mary the Mother of God:
Psalm 2:7-9 I will tell of the decree of the LORD: He said to me, “You are my son, today I have begotten you. Ask of me, and I will make the nations your heritage, and the ends of the earth your possession.  You shall break them with a rod of iron, and dash them in pieces like a potter’s vessel.” (cf. Rev 12:5)
Revelation 19:13-16 He is clad in a robe dipped in blood, and the name by which he is called is The Word of God.  And the armies of heaven, arrayed in fine linen, white and pure, followed him on white horses.  From his mouth issues a sharp sword with which to smite the nations, and he will rule them with a rod of iron; he will tread the wine press of the fury of the wrath of God the Almighty. On his robe and on his thigh he has a name inscribed, King of kings and Lord of lords. (cf. Rev 12:5)
Psalm 2:7-9 is a messianic passage, which Christians believe refers to Jesus. Revelation 19:13-16 clearly refers to Jesus, from the description of “Word of God” (John 1) and reference to Psalm 2. “Rule them with a rod of iron” (19:15) is almost identical to 12:5.
We also know for sure it is Jesus by a comparison with Revelation 17:14: “they will make war on the Lamb, and the Lamb will conquer them, for he is Lord of lords and King of kings, . . .” “Lamb” is used many times in the book of Revelation, with clear reference to Jesus, referring to a “slain” Lamb (5:6, 12; 13:8), “blood of the Lamb” (7:14: 12:11), worship of the Lamb (5:8, 12-13), “twelve apostles of the Lamb” (21:14), etc.
The next seemingly undeniable clue is the phrase “caught up to God and to his throne” (12:5). The association of the Lamb (Jesus) and His sitting on or being near God’s “throne” occurs in nine passages in the book of Revelation 12 (5:6, 13; 6:16; 7:9-10, 17 [the latter verse states “the Lamb in the midst of the throne”]; 22:1, 3).
If we’re talking about Jesus’ mother, that has to be Mary, because Jesus wasn’t born of the Church; He set up the Church (Matthew 16). Jesus was not a product of the Church, since He preceded it and initiated it. Therefore, that part is specifically talking about Mary. The Bible never uses a terminology of Jesus being a “child” (Rev 12:5) of the Church.
He is the child of God the Father (His Divine Nature) and of Mary (as a person with both a Divine and human nature). The Church is “of Christ”; Christ is not “of the Church”; let alone its “child.” Those categories are biblically ludicrous and indeed almost blasphemous.
“Caught up to God and to his throne” (12:5) can’t mean “the twelve thrones” referred to in Matt 19:18 (cf. Lk 22:30; Rev 4:4; 11:16) because it says “His [i.e., God’s] throne.” Only Jesus is connected directly with that, because He is God. And so we see Jesus (unlike any created men) sitting on God’s throne (Matt 19:28; 25:31; Heb 1:8; Rev 7:17; 22:1, 3).
One can cite many Protestant commentators regarding this Marian interpretation of Revelation 12:5. Here is a sampling:
Ellicott’s Commentary for English Readers states: “There can be no doubt that this man child is Christ. . . . who is to have, not His own people, but all nations as His inheritance (Psalm 2:7-9), . . .”
Meyer’s NT Commentary: “These words taken from Psalm 2:9 . . . make it indubitable that the child born of the woman is the Messiah; . . .”
Pulpit Commentary: “This reference and Psalm 2:9 leave no doubt as to the identification of the man child. It is Christ who is intended.”
Coffman’s Commentaries on the Bible: “[T]he pregnant woman, the travailing in birth, and the delivery of a man child in this passage can mean nothing else except the birth of Christ; and the compression of Jesus’ whole biography into such a short space is perfectly in harmony with what the author did by presenting the entire Old Testament history in a single verse (Revelation 12:4). To suppose that the birth is not included here would make the passage mean that the woman brought forth his death and resurrection; because the emphatic statements of her pregnancy and her being delivered clearly makes her the achiever of whatever happened in Revelation 12:5. This therefore has to be a reference to Jesus’ physical birth in Bethlehem.”