Shulchan Aruch and R'Ma (YD 364:4):
אִם מָצְאוּ יִשְׂרָאֵל הָרוּג, יִקְבְּרוּהוּ כְּמוֹ שֶׁמְּצָאוּהוּ, בְּלֹא תַּכְרִיכִין, וְלֹא יַחְלְצוּ בּוֹ אֲפִלּוּ מִנְעָלָיו. הַגָּה: וְכֵן עוֹשִׂין לְיוֹלֶדֶת שֶׁמֵּתָה, ... וְנָהֲגוּ שֶׁאֵין עוֹשִׂין לָהֶם תַּכְרִיכִין כִּשְׁאָר מֵתִים, רַק קוֹבְרִין אוֹתָן בְּבִגְדֵיהֶם, וּלְמַעְלָה מֵהֶם סָדִין, כִּשְׁאָר מֵתִים.
If they found a slain Jew, they should bury him [in the same condition] as they found him, without shrouds, and they do not even remove his shoes.... The same is done to a woman who died in childbirth... The accepted practice is that one makes no shrouds for them as [for] other dead, but one buries them in their garments over which [they place] a sheet as [in the case] of other dead.
Question: At what point in the birth process is the woman's death called a death at childbirth, in regard to not burying her with tachricim (shrouds)? At what point does it begin? From the beginning of labor? If so what point is the beginning? Until when? Until the completion of the delivery of the child? What if complications began at childbirth and the actual death occurred later on?