Lots of possibilities and no certainties here. It could be...

[list]1. The people of God. If the woman is Israel and the child is the Church, the stars could be Satan’s attack on the faithful in both. (Dan. 8.10)
2. God’s angels (Jude 6; 2 Pet. 2.4; cf. also Isa. 24.21)
3. Literal stars (Isa. 40.26) . The well-ordered movements of the heavenly bodies break down into chaos.
4. If the woman is the Church and the child is the 144,000, the stars could be the martyrs of the Tribulation. John may also have in mind the martyrs before Christ (Heb. 11.32ff.) and after Christ’s ascension (Mt. 23.35).
5. If the woman is Israel and the child is Christ, the stars could represent the destruction of Israel by Babylon.
6. If the woman is Mary and the child is Christ, the stars could represent the chaos that Satan works to bring to God’s plan of salvation. Isa. 13.10, 17.
7. John is indicating nothing more than a great pageant enacted in the heavens.
8. It is poetic language for great devastations such as wars.[/list]

I don't think there's anything about these stars, though, that tie in with the star of Bethlehem.

What are the "stars of heaven" that Satan's tail sweeps down to the earth (Rev. 12.1-9)?

[list]1. These are described as a "sign" that appears "in heaven".
2. The woman, who is a "great sign in heaven" has twelve stars above her head, a crown.
3. The stars of heaven are cast to the earth before war arose in heaven. These stars are cast to the earth before Satan and "his angels" lose their place in heaven. Therefore they don't seem to be Satan's Angels.
4. This passage also ties in with the star of Bethlehem, and astrological signs including the moon being under Virgos feet, clothed with the sun, a comet signifying birth and either Hydra or a combination of Scorpio and Libra.[/list]