Which direction should one face upon sleeping?
From North to South: Just as it is forbidden for one to face East or West when having a bowel movement, similarly it is forbidden to sleep facing East or West with one’s wife together in bed, when one has intention to have relations. Thus, one must align the bed to face from north to south [or vice versa]. It is proper to be careful in the above even when one’s wife is not with him in the same bed. [The bed is to be aligned with its head in the North and its end in the South. This means that the couple are to sleep with their head to the North and feet to the south.]
What to do if one is unable to align the bed from North to South? If one is unable to easily align the bed in a north to south direction, then there is no prohibition for him to align his bed from East to West, as in such a case one may rely on the opinion of the Zohar which holds that even initially one is required to face the bed from East to West [and not from North to South]. [Accordingly, if a couple is a guest in a room, they may sleep there even if the bed is aligned from east to west if it is difficult to maneuver or if they do not have permission to do so.]
A married couple is to align the bed in their room from North to South. If this is difficult to accomplish they may align the bed from East to West. [The Mekubalim however rule that one must always align the bed from East to West and so conclude some Poskim.]
Are we particular in this matter even today?
Yes. One is to be particular in this matter even today.
May one sleep with his feet or head towards the door of the room?
It is permitted to sleep facing the door of a room in any direction that one chooses, whether his head is facing the door or his feet are facing the door. There is no known source in Judaism, neither in Halacha or in Kabbala, that restricts the sleeping directions of a person who is sleeping facing the door of a room. Furthermore, the Poskim omit this topic writing any restriction in this matter within the Halachic topic of bed directions, hence solidifying that no such prohibition exists. Nonetheless, it is customary amongst many people to avoid sleeping with one’s feet vertically opposite the door due to it being similar to the direction that a corpse feet faces the opening of the room. [Practically, one who has not received this custom as a family tradition is not required to start keeping it. However one who has traditionally guarded this custom is to continue doing so.]
Segula for Male Children
Placing the bed from North to South [is a Segula] for having male children.
Segula for healthy pregnancy
In addition to the above, placing the bed from North to South [is a Segula] for healthy pregnancies without miscarriage.
 Admur Kama 3:9-10. Michaber 3:6; Omitted in Basra and Siddur; See Siddur Yaavetz Mosach Hashabbos Mitos Kesef 4:2 Part 2; Taharas Yisrael 240:89; Sheyikadesh Atzmo [Nachmanson-2015] p. 328-334
 Admur Kama 3:9; Michaber 3:6 and 240:17; Rambam Beis Habechira 7:9; based on Rashi Brachos 5b; Reply of Rebbe Rayatz to Rav Chadakov, printed in Kuntrus Ateres Zekeinim , brought in Sheyikadesh Atzmo 28 footnote 4
Other Opinions: The M”A 3:7 and Admur 3:10 brings the Zohar who rules the bed is to be aligned from East to West. The Arizal in Shaar Hamitzvos, and Rameh 3 [Harav Menachem Ezaryah], rule like the Zohar. So also concludes Birkeiy Yosef 3:2 stating that even Rashi retracted this ruling in his Sefer Likkutei Pardes. So rules also Shev Yaakov 3 like Zohar; The Olas Tamid 3:6 concludes that one may follow whichever opinion he chooses; Kaf Hachaim 3:16 concludes one is to follow the Zohar and Arizal; The custom of the Munkatcher was like the Zohar. [Darkei Chaim Veshalom 344]; Vayeishev Hayam 2 concludes that most Poskim rule like the Zohar. The M”B 3:11 and Piskeiy Teshuvos 240:31 rule like Admur that one is to initially place it from North to South.
Regarding why we prohibit marital relations from East to West [According to Admur] even though it is surrounded by walls: This question is addressed by the Levush and Olas Tamid 3:6. The M”A 3:7 explains that in a bedroom the Shechina resides, in contrast to a bathroom, and hence one must beware of the above despite there being walls. Alternatively, since the only way to have marital relations is within a house therefore the law applies.
Placing the bed from North to South [is a Segula] for having male children: The Talmud and Poskim record that placing the bed from North to South is a Segula for having male children [Rebbe Chama Bar Rebbe Chanina in Brachos 5a in the name of Rebbe Yitzchak; Levush 240:17; Olas Tamid 3:6] This is based on the verse “And in the North their stomach will be filled and they will be satisfied with male offspring.” [Psalms 17:14; brought in Brachos ibid] See Piskeiy Teshuvos 240 footnote 235; Sheyikadesh Atzmo 28:1; See however Igeres Hakodesh of the Ramban Chapter 3 who interprets this statement to be not literal, as certainly the position of the bed does not effect male childbirth and rather it refers to other aspects
 The reason: The reason for this is because [it is not honorable to] the Divine presence, [which] is found in the West, and faces the East. [See Rashi ibid; Admur Basra 3:6 and Kama 3:7]
 The wording in Admur ibid [which is the wording of Rashi] is “that the head of the bed and its end be aligned one end at the North and the other at the South.” Vetzaruch Iyun at this seemingly superfluous wording.
 Lit. Nachon
 Admur ibid; Michaber ibid; Rambam ibid; Beis Yosef 3; Darkei Moshe 240:3; Perisha 240:23
Other opinions: Some Poskim rule that the above is only proper if the person is sleeping without clothing. [M”B 3:12 in name of Artzos Hachaim] Others are lenient in all cases. [See Sheyikadesh Atzmo 28 footnote 4]
 Michaber 240:17; M”B 3:11 in name of Lechem Chamudos; Madanei Yom Tov on Rosh Brachos 1:50
 Sheyikadesh Atzmo 28:1
 Admur Kama 3:10
 Parshas Bamidbar brought in Bach, and in Or Tzadikim 27:12; Arizal in Shaar Hamitzvos Bereishis
Which end is placed by the East and which by the West? Some rule that the bed must be from East to West, with its head by East and its legs [end] by West. [Arizal in Shaar Hamitzvos Bireishis, brought in M”A 3:7; M”B 3:11, Kaf Hachaim 240:95; implication of the wording of Admur ibid-Sheyikadesh Atzmo 28:3]. However, other Poskim rule that the head is to be by the west and feet by the East. [Rameh 3, brought in M”A 3:7; M”B 3:11; Siddur Yaavetz]
The reason behind the Kabalistic ruling: The Arizal [Shaar Hamitzvos Bireishis] explains that this alignment corresponds to the directions that Adam was created in, as well as the positioning of the Primordial man of Atzilus, of which the head is by the East which corresponds to Daas, while the feet are by the West. The right hand faces the South which is Chesed and the left hand faces North which is Gevurah. [Brought in Kaf Hachaim 3:16]
 Sheyikadesh Atzmo 28:2
 Rav Asher Lemel Cohen, and so is evident from all Poskim ibid that discuss the Halacha. However see Hagahos Kneses Hagedola 3:4 that today the world is no longer accustomed to be careful in this.
 See Kama 3:9-10. Michaber 3:6; Omitted in Basra
 See Poskim in Nitei Gavriel 5:1 footnote 4; Custom of many; Heard from Harav Eliyahu Landa; Harav A.L. Kohen; Darkei Chesed p. 32 that so was done to the Rebbe Rashab; Gesher Hachaim p. 20
 This is the traditional ruling regarding all matters that are not Halachicly based, that one cannot enforce their practice upon others.
 Rav Eliyahu Landa and Rav Kohen ibid
The reason: As even customs that have no written source are customarily respected, such as the custom of pregnant woman not to enter a cemetery [see Minchas Yitzchak 10:42; Nitei Gavriel Aveilus 2:84-4; Our Sefer on Rosh Hashanah Supplement “Visiting a cemetery” Halacha 22]; or the custom not to step over a child, or not to allow a child to look in the mirror until he grows teeth. [see Beir Moshe 36]; or the custom not to have two people dress a child or not to place a candle on the floor. [Rav Eliyahu Landa]
 Brachos 5a [stated by Rebbe Chama Bar Rebbe Chanina in the name of Rebbe Yitzchak]; Levush 240:17; Olas Tamid 3:6; This is based on the verse “And in the North their stomach will be filled and they will be satisfied with male offspring.” [Psalms 17:4 ; brought in Brachos ibid]
 Brachos 5a [stated by Rav Nachman the son of Yitzchak]; This is learned from a juxtaposition with the verse: “And her days were complete to give birth and she had twins in her stomach”