There are actually two contrasting historical threads about the birth of Jesus. There is the fairly clear biblical account and there is tradition that basically sources to one document.
For example, there is no mid-wife mentioned in scripture, but is mentioned in the other source.
The primary text leading to various Marian dogmas and doctrines comes out from the Infancy Gospel of James.
Here is the primary alternate tradition that gave rise to so much controversy. Emphasis mine.
And I [Joseph] said: I am seeking an Hebrew midwife. And she answered and said unto me: Art thou of Israel? And I said to her: Yes. And she said: And who is it that is bringing forth in the cave? And I said: A woman betrothed to me. And she said to me: Is she not thy wife? And I said to her: It is Mary that was reared in the temple of the Lord, and I obtained her by lot as my wife. And yet she is not my wife, but has conceived of the Holy Spirit. And the widwife said to him: Is this true? And Joseph said to her: Come and see. And the midwife went away with him. And they stood in the place of the cave, and behold a luminous cloud overshadowed the cave. And the midwife said: My soul has been magnified this day, because mine eyes have seen strange things -- because salvation has been brought forth to Israel. And immediately the cloud disappeared out of the cave, and a great light shone in the cave, so that the eyes could not bear it. And in a little that light gradually decreased, until the infant appeared, and went and took the breast from His mother Mary. And the midwife cried out, and said: This is a great day to me, because I have seen this strange sight. And the midwife went forth out of the cave, and Salome met her. And she said to her: Salome, Salome, I have a strange sight to relate to thee: a virgin has brought forth -- a thing which her nature admits not of. Then said Salome: As the Lord my God liveth, unless I thrust in my finger, and search the parts, I will not believe that a virgin has brought forth.
- And the midwife went in, and said to Mary: Show thyself; for no small controversy has arisen about thee. And Salome put in her finger, and cried out, and said: Woe is me for mine iniquity and mine unbelief, because I have tempted the living God; and, behold, my hand is dropping off as if burned with fire.
In that historic passage, we find the ideas of a helping midwife, the "birthing" at Mary's side (east gate), the no-pain birth, and the ever-virgin before, during, and after Jesus' birth.
In another part of the same gospel, we must and do also find it's explanation of scripture's mentioning of Jesus' brothers. They were step-brothers from Joseph who had been married prior to Mary.
With that tradition, we may use it to shed light on how scripture is alternatively seen.
As mentioned, the brothers and sisters of Jesus become the step-siblings of Jesus. Later, with Jerome, we find the explanation they are cousins.
Ezekiel is reinterpreted to show the east gate birth and ever-virgin; that it was "opened" and shut forever.
Now when the prince shall prepare a voluntary burnt offering or peace offerings voluntarily unto the LORD, one shall then open him the gate that looketh toward the east, and he shall prepare his burnt offering and his peace offerings, as he did on the sabbath day: then he shall go forth; and after his going forth one shall shut the gate. Eze 46:12
As late as John of Damascus, this birth from the east gate idea continued.
But just as He who was conceived kept her who conceived still virgin, in like manner also He who was born preserved her virginity intact, only passing through her and keeping her closed2460. The conception, indeed, was through the sense of hearing, but the birth through the usual path by which children come, although some tell tales of His birth through the side of the Mother of God. For it was not impossible for Him to have come by this gate, without injuring her seal in anyway.
John of Damascus
The idea that Mary had no pain in giving birth also sources to that text; the baby just appears at her side. Her birth state remained intact. The subsequent idea of Mary's sinlessness at her birth being the reason for that came centuries later; that idea was formally defined in 1854. Birth from her side or the baby just appearing at her side from out of the light meant no pain.
That tradition is contrasted with this.
And she being with child cried, travailing in birth, and pained to be delivered. Rev 12:2
But when the fulness of the time was come, God sent forth his Son, made of a woman, made under the law, Gal 4:4
And the Word was made flesh, and dwelt among us, (and we beheld his glory, the glory as of the only begotten of the Father,) full of grace and truth. John 1:4
The birth of Christ as shown in Luke 2 is further explained throughout scripture as being a normal birth in the normal way, made of a woman, made of flesh, without a midwife's help, and having brothers and sisters from the same mother is all clear enough.
The alternative view that Mary needed help, even though she supposedly had no pain, as the baby simply appears, and she remains as she was in the child birth state, source to that one document.
So, one may either stick to scripture or embellish and view it with tradition's glasses.