If a woman was taken to the hospital on Shabbat because she thought it was time to give birth, but the hospital staff examined her and determined that the time had not yet come, is she allowed to return home, or must she wait until after Shabbat?
The Poskim rule that if the hospital offers the woman a room where she can comfortably remain until after Shabbat, then she should stay there in the hospital until after Shabbat. Far more commonly, however, the hospital staff does not offer her a room if she is not yet ready to give birth, and the choice is thus either to be driven home or to remain in the lobby until Shabbat ends. A woman in her ninth month pregnancy clearly has the status of a Holeh (ill patient), for whom rabbinic prohibitions are, as a general rule, suspended when necessary to assist the patient. Therefore, it would certainly be permissible for the woman to be driven home by a non-Jew so she can be comfortable at home. This is especially true if she has young children at home who need her care, as all children have the de facto status of "ill patients," since they are fragile and tender, and require care. Yet another factor, noted by the Shemirat Shabbat Ke’hilchatah (Rav Yehoshua Neuwirth, 1927-2013), is that a woman in her ninth month of pregnancy needs to rest so she will have the strength to go through labor successfully. For this reason, too, she is permitted to be driven back home on Shabbat, so she will not have to remain in the hospital lobby.
Once she is being driven home, her husband (or her mother, or whoever else accompanied her to the hospital) may return home with her.
Summary: If a woman in her ninth month of pregnancy goes to the hospital on Shabbat for what turns out to be a "false alarm," and the hospital does not give her a room where she could comfortably stay until after Shabbat, she may be driven home by a non-Jew. Her husband (or whoever else accompanied her) may be driven with her, as well.
