Uterus

Last updated
Uterus
Illu cervix.svg
Diagram of human uterus and surrounding structures
Details
Precursor Paramesonephric duct
System Reproductive system
Artery Ovarian artery and uterine artery
Vein Uterine veins
Lymph Body and cervix to internal iliac lymph nodes, fundus to para-aortic lymph nodes, lumbar and superficial inguinal lymph nodes.
Identifiers
Latin uterus
Greek ὑστέρα (hystéra)
MeSH D014599
TA98 A09.1.03.001
TA2 3500
FMA 17558
Anatomical terminology

The uterus (from Latin uterus, pl.: uteri) or womb ( /wm/ ) is the organ in the reproductive system of most female mammals, including humans, that accommodates the embryonic and fetal development of one or more embryos until birth. The uterus is a hormone-responsive sex organ that contains glands in its lining that secrete uterine milk for embryonic nourishment.

Contents

The term uterus is also applied to analogous structures in some non-mammalian animals.

In the human, the lower end of the uterus is a narrow part known as the isthmus that connects to the cervix, leading to the vagina. The upper end, the body of the uterus, is connected to the fallopian tubes, at the uterine horns, and the rounded part above the openings to the fallopian tubes is the fundus. The connection of the uterine cavity with a fallopian tube is called the uterotubal junction. The fertilized egg is carried to the uterus along the fallopian tube. It will have divided on its journey to form a blastocyst that will implant itself into the lining of the uterus – the endometrium, where it will receive nutrients and develop into the embryo proper and later fetus for the duration of the pregnancy.

In the human embryo, the uterus develops from the paramesonephric ducts, which fuse into the single organ known as a simplex uterus. The uterus has different forms in many other animals and in some it exists as two separate uteri known as a duplex uterus.

In medicine and related professions, the term uterus is consistently used, while the Germanic-derived term womb is commonly used in everyday contexts. Events occurring within the uterus are described with the term in utero.

Structure

Different regions of the uterus displayed and labelled using a 3D medical illustration 3D Medical Animation Uterus.jpg
Different regions of the uterus displayed and labelled using a 3D medical illustration

In humans, the uterus is located within the pelvic region immediately behind and almost overlying the bladder, and in front of the sigmoid colon. The human uterus is pear-shaped and about 7.6 cm (3.0 in) long, 4.5 cm (1.8 in) broad (side to side), and 3.0 cm (1.2 in) thick. [1] [2] A typical adult uterus weighs about 60 grams. The uterus can be divided anatomically into four regions: the fundus – the uppermost rounded portion of the uterus above the openings of the fallopian tubes, [3] the body, the cervix, and the cervical canal. The cervix protrudes into the vagina. The uterus is held in position within the pelvis by ligaments, which are part of the endopelvic fascia. These ligaments include the pubocervical ligaments, the cardinal ligaments, and the uterosacral ligaments. It is covered by a sheet-like fold of peritoneum, the broad ligament. [4]

Layers

Uterine wall thickness (cm) [5]
LocationMean (mm)Range (mm)
Anterior wall2317 - 25
Posterior wall2115 - 25
Fundus2015 - 22
Isthmus108 - 22
Vertical section of mucous membrane of human uterus Gray1169.png
Vertical section of mucous membrane of human uterus

The uterus has three layers, which together form the uterine wall. From innermost to outermost, these layers are the endometrium, myometrium, and perimetrium. [6]

The endometrium is the inner epithelial layer, along with its mucous membrane, of the mammalian uterus. It has a basal layer and a functional layer; the functional layer thickens and then is shed during the menstrual cycle or estrous cycle. During pregnancy, the uterine glands and blood vessels in the endometrium further increase in size and number and form the decidua. Vascular spaces fuse and become interconnected, forming the placenta, which supplies oxygen and nutrition to the embryo and fetus. [7] [8]

The myometrium of the uterus mostly consists of smooth muscle. The innermost layer of myometrium is known as the junctional zone, which becomes thickened in adenomyosis. [9]

The perimetrium is a serous layer of visceral peritoneum. It covers the outer surface of the uterus. [10]

Surrounding the uterus is a layer or band of fibrous and fatty connective tissue called the parametrium that connects the uterus to other tissues of the pelvis.

Commensal and mutualistic organisms are present in the uterus and form the uterine microbiome. [11] [12] [13] [14]

Support

Uterus covered by the broad ligament Gray1161.png
Uterus covered by the broad ligament

The uterus is primarily supported by the pelvic diaphragm, perineal body, and urogenital diaphragm. Secondarily, it is supported by ligaments, including the peritoneal ligament and the broad ligament of uterus. [15]

Major ligaments

The uterus is held in place by several peritoneal ligaments, of which the following are the most important (there are two of each):

NameFromTo
Uterosacral ligaments Posterior cervixAnterior face of sacrum
Cardinal ligaments Side of the cervix Ischial spines
Pubocervical ligaments [15] Side of the cervix Pubic symphysis

Axis

Normally, the human uterus lies in anteversion and anteflexion. In most women, the long axis of the uterus is bent forward on the long axis of the vagina, against the urinary bladder. This position is referred to as anteversion of the uterus. Furthermore, the long axis of the body of the uterus is bent forward at the level of the internal os with the long axis of the cervix. This position is termed anteflexion of the uterus. [16] The uterus assumes an anteverted position in 50% of women, a retroverted position in 25% of women, and a midposed position in the remaining 25% of women. [1]

Position

Uterus shown in position in the body Figure 28 02 01.JPG
Uterus shown in position in the body

The uterus is located in the middle of the pelvic cavity, in the frontal plane (due to the broad ligament of the uterus). The fundus does not extend above the linea terminalis , while the vaginal part of the cervix does not extend below the interspinal line. The uterus is mobile and moves posteriorly under the pressure of a full bladder, or anteriorly under the pressure of a full rectum. If both are full, it moves upwards. Increased intra-abdominal pressure pushes it downwards. The mobility is conferred to it by a musculo-fibrous apparatus that consists of suspensory and sustentacular parts. Under normal circumstances, the suspensory part keeps the uterus in anteflexion and anteversion (in 90% of women) and keeps it "floating" in the pelvis. The meanings of these terms are described below:

1. Anteversion with slight anteflexion
2. Anteversion with marked anteflexion
3. Anteversion with retrocession
4. Retroversion
5. Retroversion with retroflexion Positions of the human uterus 1.png
1. Anteversion with slight anteflexion
2. Anteversion with marked anteflexion
3. Anteversion with retrocession
4. Retroversion
5. Retroversion with retroflexion
DistinctionMore commonLess common
Position tipped"Anteverted": Tipped forward"Retroverted": Tipped backwards
Position of fundus"Anteflexed": Fundus is pointing forward relative to the cervix"Retroflexed": Fundus is pointing backward

The sustentacular part supports the pelvic organs and comprises the larger pelvic diaphragm in the back and the smaller urogenital diaphragm in the front.

The pathological changes of the position of the uterus are:

In cases where the uterus is "tipped", also known as retroverted uterus, the woman may have symptoms of pain during sexual intercourse, pelvic pain during menstruation, minor incontinence, urinary tract infections, fertility difficulties, [17] and difficulty using tampons. A pelvic examination by a doctor can determine if a uterus is tipped. [18]

Blood, lymph, and nerve supply supply

Diagram of uterine blood supply Uterine arterial vasculature.svg
Diagram of uterine blood supply

The human uterus is supplied by arterial blood both from the uterine artery and the ovarian artery. Another anastomotic branch may also supply the uterus from anastomosis of these two arteries.

Afferent nerves supplying the uterus are T11 and T12. Sympathetic supply is from the hypogastric plexus and the ovarian plexus. Parasympathetic supply is from the S2, S3 and S4 nerves.

Development

Differentiation of uterus The uterus differentiates from the fetal Mullerian ducts..jpg
Differentiation of uterus

Bilateral Müllerian ducts form during early human fetal life. In males, anti-Müllerian hormone (AMH) secreted from the testes leads to the ducts' regression. In females, these ducts give rise to the fallopian tubes and the uterus. In humans, the lower segments of the two ducts fuse to form a single uterus; in cases of uterine malformations this fusion may be disturbed. The different uterine morphologies among the mammals are due to varying degrees of fusion of the Müllerian ducts.

Various congenital conditions of the uterus can develop in utero. Though uncommon, some of these are didelphic uterus, bicornate uterus and others. [19]

See also List of related male and female reproductive organs.

Function

Maximum penetration depth of the penis Human female inner genitalia.png
Maximum penetration depth of the penis

The primary reproductive function of the human uterus is to prepare for the implantation of a zygote, a fertilized ovum, and maintenance of pregnancy if implantation occurs. [20] Traveling along the fallopian tube on its way to the uterine cavity, the zygote divides mitotically to become a blastocyst, which ultimately attaches to the uterine wall and implants into the endometrium. [3] The placenta later develops to nourish the embryo, which grows through embryonic and fetal development until childbirth. During this process, the uterus grows to accommodate the growing fetus. [21] When normal labor begins, the uterus forcefully contracts as the cervix dilates, which results in delivery of the infant. [21]

In the absence of pregnancy, menstruation occurs. [20] The withdrawal of female sex hormones, estrogen and progesterone, which occurs in the absence of fertilization, triggers the shedding of the functional layer of the endometrium. [20] This layer is broken down, shed, and restored in anticipation of the next menstrual cycle. [20] The average bleeding duration during menses is 5-7 days after which the menstrual cycle begins again. [22]

Clinical significance

During pregnancy, the growth rate of the fetus can be assessed by measuring the fundal height.

Some pathological states include:

Transvaginal ultrasonography showing a uterine fluid accumulation in a postmenopausal woman. Endometrial fluid accumulation, postmenopausal.jpg
Transvaginal ultrasonography showing a uterine fluid accumulation in a postmenopausal woman.

Malformations

Four types of uterine malformation Uterine malformation.jpg
Four types of uterine malformation

Uterine malformations are mainly congenital malformations, and include uterus didelphys , bicornuate uterus and septate uterus. Congenital absence of the uterus is known as Müllerian agenesis.

Surgery

A hysterectomy is the surgical removal of the uterus, which may be carried out for a number of reasons including the ridding of tumours both benign and malignant. A complete hysterectomy involves the removal of the body, fundus, and cervix of the uterus. A partial hysterectomy may just involve the removal of the uterine body while leaving the cervix intact. It is the most commonly performed gynecological surgical procedure.

Transplants

Uterus transplantations have been successfully carried out in a number of countries. The transplant is intended to be temporary – recipients will have to undergo a hysterectomy after one or two successful pregnancies. This is done to avoid the need to take immunosuppressive drugs for life with a consequent increased risk of infection. [26]

The procedure remains the last resort: it is as of 2023, a relatively new and somewhat experimental procedure, performed only by certain specialist surgeons in select centres, it is expensive and unlikely to be covered by insurance, and it involves risk of infection and organ rejection. Some ethics specialists consider the risks to a live donor too great, and some find the entire procedure ethically questionable, especially since the transplant is not a life-saving procedure. [27] [28] [29]

Other animals

Most animals that lay eggs, such as birds and reptiles, including most ovoviviparous species, have an oviduct instead of a uterus. However, recent research into the biology of the viviparous (not merely ovoviviparous) skink Trachylepis ivensi has revealed development of a very close analogue to eutherian mammalian placental development. [30]

In monotremes, mammals which lay eggs, namely the platypus and the echidnas, either the term uterus or oviduct is used to describe the same organ, but the egg does not develop a placenta within the mother and thus does not receive further nourishment after formation and fertilization.

Marsupials have two uteri, each of which connect to a lateral vagina and both use a third, middle "vagina", which functions as the birth canal. [31] [32] Marsupial embryos form a choriovitelline placenta (which can be thought of as something between a monotreme egg and a "true" placenta), in which the egg's yolk sac supplies a large part of the embryo's nutrition but also attaches to the uterine wall and takes nutrients from the mother's bloodstream. However, bandicoots also have a rudimentary chorioallantoic placenta, similar to those of placental mammals.

The fetus usually develops fully in placental mammals and only partially in marsupials including kangaroos and opossums. In marsupials, the uterus forms as a duplex organ of two uteri. In monotremes such as the platypus, the uterus is duplex and rather than nurturing the embryo, secretes the shell around the egg. It is essentially identical with the shell gland of birds and reptiles, with which the uterus is homologous. [33]

In mammals, the four main forms of the uterus are: duplex, bipartite, bicornuate and simplex. [34]

Duplex
There are two wholly separate uteri, with one oviduct each. Found in marsupials (such as kangaroos, Tasmanian devils, opossums, etc.), rodents (such as mice, rats, and guinea pigs), and lagomorpha (rabbits and hares).
Bipartite
The two uteri are separate for most of their length, but share a single cervix. Found in ruminants (deer, moose, elk etc.), hyraxes, cats, and horses.
Bicornuate
The upper parts of the uterus remain separate, but the lower parts are fused into a single structure. Found in dogs, pigs, elephants, whales, dolphins, [35] and tarsiers, and strepsirrhine primates among others.
Simplex
The entire uterus is fused into a single organ. [33] Found in higher primates (including humans and chimpanzees). Occasionally, some individual females (including humans) may have a bicornuate uterus, a uterine malformation where the two parts of the uterus fail to fuse completely during fetal development.

Two uteri usually form initially in a female and usually male fetus, and in placental mammals, they may partially or completely fuse into a single uterus depending on the species. In many species with two uteri, only one is functional. Humans and other higher primates such as chimpanzees, usually have a single completely fused uterus, although in some individuals, the uteri may not have completely fused.

Additional images

See also

Related Research Articles

<span class="mw-page-title-main">Cervix</span> Lower part of the uterus in the female reproductive system

The cervix or cervix uteri is a dynamic fibromuscular organ of the female reproductive system that connects the vagina with the uterine cavity. The human cervix has been documented anatomically since at least the time of Hippocrates, over 2,000 years ago[citation needed]. The cervix is approximately 4 cm long with a diameter of approximately 3 cm and tends to be described as a cylindrical shape, although the front and back walls of the cervix are contiguous. The size of the cervix changes throughout a women's life cycle. For example, during their fertile years of the reproductive cycle, females tend to have a larger cervix vis á vis postmenopausal females; likewise, females who have produced offspring have a larger sized cervix than females who have not produced offspring.

<span class="mw-page-title-main">Endometrium</span> Inner mucous membrane of the mammalian uterus

The endometrium is the inner epithelial layer, along with its mucous membrane, of the mammalian uterus. It has a basal layer and a functional layer: the basal layer contains stem cells which regenerate the functional layer. The functional layer thickens and then is shed during menstruation in humans and some other mammals, including apes, Old World monkeys, some species of bat, the elephant shrew and the Cairo spiny mouse. In most other mammals, the endometrium is reabsorbed in the estrous cycle. During pregnancy, the glands and blood vessels in the endometrium further increase in size and number. Vascular spaces fuse and become interconnected, forming the placenta, which supplies oxygen and nutrition to the embryo and fetus. The speculated presence of an endometrial microbiota has been argued against.

<span class="mw-page-title-main">Placenta</span> Organ that connects the fetus to the uterine wall

The placenta is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation. It plays critical roles in facilitating nutrient, gas and waste exchange between the physically separate maternal and fetal circulations, and is an important endocrine organ, producing hormones that regulate both maternal and fetal physiology during pregnancy. The placenta connects to the fetus via the umbilical cord, and on the opposite aspect to the maternal uterus in a species-dependent manner. In humans, a thin layer of maternal decidual (endometrial) tissue comes away with the placenta when it is expelled from the uterus following birth. Placentas are a defining characteristic of placental mammals, but are also found in marsupials and some non-mammals with varying levels of development.

The oviduct in vertebrates is the passageway from an ovary. In human females, this is more usually known as the fallopian tube or uterine tube. The eggs travel along the oviduct. These eggs will either be fertilized by spermatozoa to become a zygote, or will degenerate in the body. Normally, these are paired structures, but in birds and some cartilaginous fishes, one or the other side fails to develop, and only one functional oviduct can be found.

<span class="mw-page-title-main">Amnion</span> Innermost membranous sac that surrounds and protects the developing embryo

The amnion is a membrane that closely covers the human and various other embryos when first formed. It fills with amniotic fluid, which causes the amnion to expand and become the amniotic sac that provides a protective environment for the developing embryo. The amnion, along with the chorion, the yolk sac and the allantois protect the embryo. In birds, reptiles and monotremes, the protective sac is enclosed in a shell. In marsupials and placental mammals, it is enclosed in a uterus.

<span class="mw-page-title-main">Blastocyst</span> Structure formed around day 5 of mammalian embryonic development

The blastocyst is a structure formed in the early embryonic development of mammals. It possesses an inner cell mass (ICM) also known as the embryoblast which subsequently forms the embryo, and an outer layer of trophoblast cells called the trophectoderm. This layer surrounds the inner cell mass and a fluid-filled cavity known as the blastocoel. In the late blastocyst, the trophectoderm is known as the trophoblast. The trophoblast gives rise to the chorion and amnion, the two fetal membranes that surround the embryo. The placenta derives from the embryonic chorion and the underlying uterine tissue of the mother.

<span class="mw-page-title-main">Female reproductive system</span> Reproductive system of human females

The female reproductive system is made up of the internal and external sex organs that function in the reproduction of new offspring. The human female reproductive system is immature at birth and develops to maturity at puberty to be able to produce gametes, and to carry a fetus to full term. The internal sex organs are the vagina, uterus, fallopian tubes, and ovaries. The female reproductive tract includes the vagina, uterus, and fallopian tubes and is prone to infections. The vagina allows for sexual intercourse and childbirth, and is connected to the uterus at the cervix. The uterus or womb accommodates the embryo, which develops into the fetus. The uterus also produces secretions, which help the transit of sperm to the fallopian tubes, where sperm fertilize ova produced by the ovaries. The external sex organs are also known as the genitals and these are the organs of the vulva including the labia, clitoris, and vaginal opening.

<span class="mw-page-title-main">Human reproductive system</span> Organs involved in reproduction

The human reproductive system includes the male reproductive system which functions to produce and deposit sperm; and the female reproductive system which functions to produce egg cells, and to protect and nourish the fetus until birth. Humans have a high level of sexual differentiation. In addition to differences in nearly every reproductive organ, there are numerous differences in typical secondary sex characteristics.

<span class="mw-page-title-main">Decidua</span> Part of uterus modified in pregnancy

The decidua is the modified mucosal lining of the uterus that forms every month, in preparation for pregnancy. It is shed off each month when there is no fertilised egg to support. The decidua is under the influence of progesterone. Endometrial cells become highly characteristic. The decidua forms the maternal part of the placenta and remains for the duration of the pregnancy. After birth the decidua is shed together with the placenta.

<span class="mw-page-title-main">Placentation</span> Formation and structure of the placenta

Placentation refers to the formation, type and structure, or arrangement of the placenta. The function of placentation is to transfer nutrients, respiratory gases, and water from maternal tissue to a growing embryo, and in some instances to remove waste from the embryo. Placentation is best known in live-bearing mammals (theria), but also occurs in some fish, reptiles, amphibians, a diversity of invertebrates, and flowering plants. In vertebrates, placentas have evolved more than 100 times independently, with the majority of these instances occurring in squamate reptiles.

<span class="mw-page-title-main">Broad ligament of the uterus</span> Wide fold of peritoneum that connects the sides of the uterus to the walls and floor of the pelvis

The broad ligament of the uterus is the wide fold of peritoneum that connects the sides of the uterus to the walls and floor of the pelvis.

<span class="mw-page-title-main">Bicornuate uterus</span> Medical condition

A bicornuate uterus or bicornate uterus, is a type of müllerian anomaly in the human uterus, where there is a deep indentation at the fundus (top) of the uterus.

<span class="mw-page-title-main">Implantation (embryology)</span> First stage of pregnancy

Implantation, also known as nidation, is the stage in the embryonic development of mammals in which the blastocyst hatches, attaches, adheres, and invades into the wall of the female's uterus. Implantation is the first stage of gestation, and, when successful, the female is considered to be pregnant. An implanted embryo is detected by the presence of increased levels of human chorionic gonadotropin (hCG) in a pregnancy test. The implanted embryo will receive oxygen and nutrients in order to grow.

<span class="mw-page-title-main">Vesicouterine pouch</span> Fold of peritoneum in human female anatomy

In human female anatomy, the vesicouterine pouch, also uterovesicle pouch, is a fold of peritoneum over the uterus and the bladder. Like the rectouterine pouch, it is a female pelvic recess, but shallower and closer to the anterior fornix of the vagina.

<span class="mw-page-title-main">Uterine gland</span>

Uterine glands or endometrial glands are tubular glands, lined by a simple columnar epithelium, found in the functional layer of the endometrium that lines the uterus. Their appearance varies during the menstrual cycle. During the proliferative phase, uterine glands appear long due to estrogen secretion by the ovaries. During the secretory phase, the uterine glands become very coiled with wide lumens and produce a glycogen-rich secretion known as histotroph or uterine milk. This change corresponds with an increase in blood flow to spiral arteries due to increased progesterone secretion from the corpus luteum. During the pre-menstrual phase, progesterone secretion decreases as the corpus luteum degenerates, which results in decreased blood flow to the spiral arteries. The functional layer of the uterus containing the glands becomes necrotic, and eventually sloughs off during the menstrual phase of the cycle.

The reproductive system of an organism, also known as the genital system, is the biological system made up of all the anatomical organs involved in sexual reproduction. Many non-living substances such as fluids, hormones, and pheromones are also important accessories to the reproductive system. Unlike most organ systems, the sexes of differentiated species often have significant differences. These differences allow for a combination of genetic material between two individuals, which allows for the possibility of greater genetic fitness of the offspring.

<span class="mw-page-title-main">Fallopian tube</span> Tubes in the human female reproductive system

The fallopian tubes, also known as uterine tubes, oviducts or salpinges, are paired tubes in the human female body that stretch from the uterus to the ovaries. The fallopian tubes are part of the female reproductive system. In other vertebrates, they are only called oviducts.

<span class="mw-page-title-main">Placental expulsion</span>

Placental expulsion occurs when the placenta comes out of the birth canal after childbirth. The period from just after the baby is expelled until just after the placenta is expelled is called the third stage of labor.

Menstruation is the shedding of the uterine lining (endometrium). It occurs on a regular basis in uninseminated sexually reproductive-age females of certain mammal species.

Müllerian duct anomalies are those structural anomalies caused by errors in Müllerian duct development during embryonic morphogenesis. Factors that precipitate include genetics, and maternal exposure to teratogens.

References

  1. 1 2 Manual of Obstetrics. (3rd ed.). Elsevier 2011. pp. 1–16. ISBN   9788131225561.
  2. Donita, D'Amico (2015). Health & physical assessment in nursing. Barbarito, Colleen (3rd ed.). Boston: Pearson. p. 645. ISBN   9780133876406. OCLC   894626609.
  3. 1 2 "27.2 Anatomy and Physiology of the Female Reproductive System - Anatomy and Physiology | OpenStax". openstax.org. 25 April 2013. Retrieved 4 November 2022.
  4. Gray's Anatomy for Students, 2nd edition
  5. Nandita Palshetkar; Rishma Dhillon Pai; Hrishikesh D Pai (2012-09-30). Textbook of Hysteroscopy. JP Medical Ltd. pp. 135–. ISBN   978-93-5025-781-4.
  6. Tortora, G; Derrickson, B (2011). Principles of anatomy & physiology (13th. ed.). Wiley. p. 1105. ISBN   9780470646083.
  7. Blue Histology - Female Reproductive System Archived 2007-02-21 at the Wayback Machine . School of Anatomy and Human Biology — The University of Western Australia Accessed 20061228 20:35
  8. Guyton AC, Hall JE, eds. (2006). "Chapter 81 Female Physiology Before Pregnancy and Female Hormones". Textbook of Medical Physiology (11th ed.). Elsevier Saunders. pp. 1018ff. ISBN   9780721602400.
  9. "NCI Dictionary of Cancer Terms". National Cancer Institute. Archived from the original on 2017-12-26. Retrieved 2017-12-27.
  10. Ross, Michael H.; Pawlina, Wojciech. Histology, a text and atlas (Sixth ed.). p. 848.
  11. Franasiak, Jason M.; Scott, Richard T. (2015). "Reproductive tract microbiome in assisted reproductive technologies". Fertility and Sterility. 104 (6): 1364–1371. doi: 10.1016/j.fertnstert.2015.10.012 . ISSN   0015-0282. PMID   26597628.
  12. Verstraelen, Hans; Vilchez-Vargas, Ramiro; Desimpel, Fabian; Jauregui, Ruy; Vankeirsbilck, Nele; Weyers, Steven; Verhelst, Rita; De Sutter, Petra; Pieper, Dietmar H.; Van De Wiele, Tom (2016). "Characterisation of the human uterine microbiome in non-pregnant women through deep sequencing of the V1-2 region of the 16S rRNA gene". PeerJ. 4: e1602. doi: 10.7717/peerj.1602 . ISSN   2167-8359. PMC   4730988 . PMID   26823997.
  13. Mor, Gil; Kwon, Ja-Young (2015). "Trophoblast-microbiome interaction: a new paradigm on immune regulation". American Journal of Obstetrics and Gynecology. 213 (4): S131–S137. doi:10.1016/j.ajog.2015.06.039. ISSN   0002-9378. PMC   6800181 . PMID   26428492.
  14. Payne, Matthew S.; Bayatibojakhi, Sara (2014). "Exploring Preterm Birth as a Polymicrobial Disease: An Overview of the Uterine Microbiome". Frontiers in Immunology. 5: 595. doi: 10.3389/fimmu.2014.00595 . ISSN   1664-3224. PMC   4245917 . PMID   25505898.
  15. 1 2 The Pelvis University College Cork Archived from the original on 2008-02-27
  16. Snell, Clinical Anatomy by regions, 8th edition
  17. "Retroverted Uterus: What it is & How it Affects Pregnancy". www.womens-health.co.uk. Archived from the original on 2013-10-05.
  18. Tipped Uterus:Tilted Uterus Archived 2011-02-24 at the Wayback Machine AmericanPregnancy.org. Accessed 25 March 2011
  19. "Surgical Correction of Uterovaginal Anomalies | GLOWM". www.glowm.com. Archived from the original on 2017-12-28. Retrieved 2017-12-27.
  20. 1 2 3 4 Critchley, Hilary O. D.; Maybin, Jacqueline A.; Armstrong, Gregory M.; Williams, Alistair R. W. (2020-07-01). "Physiology of the Endometrium and Regulation of Menstruation". Physiological Reviews. 100 (3): 1149–1179. doi: 10.1152/physrev.00031.2019 . hdl: 20.500.11820/36236a4e-a35e-4818-abe3-5d8b278c66f8 . ISSN   0031-9333. PMID   32031903. S2CID   211063583.
  21. 1 2 Ameer, Muhammad Atif; Fagan, Sarah E.; Sosa-Stanley, Jessica N.; Peterson, Diana C. (2023), "Anatomy, Abdomen and Pelvis: Uterus", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID   29262069 , retrieved 2023-10-30
  22. Thiyagarajan, Dhanalakshmi K.; Basit, Hajira; Jeanmonod, Rebecca (2023), "Physiology, Menstrual Cycle", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID   29763196 , retrieved 2023-10-30
  23. Takacs P, De Santis T, Nicholas MC, Verma U, Strassberg R, Duthely L (November 2005). "Echogenic endometrial fluid collection in postmenopausal women is a significant risk factor for disease". J Ultrasound Med. 24 (11): 1477–81. doi:10.7863/jum.2005.24.11.1477. PMID   16239648. S2CID   20258522.
  24. "Cervical Stenosis - Women's Health Issues - Merck Manuals Consumer Version". Merck Manuals Consumer Version. Archived from the original on 2018-11-08. Retrieved 2018-11-07.
  25. "Myometritis - Medical Definition from MediLexicon". www.medilexicon.com. Archived from the original on 2016-12-29.
  26. Ossola, Alexandra (18 February 2014). "Everything You Need To Know About Uterus Transplants". Popular Science. Retrieved 10 October 2014.
  27. "Medical first: Baby born to woman who got new womb". Journal Star . 2006-2014 Gatehouse Media, Inc. 4 October 2014. Retrieved 4 October 2014.
  28. "BBC News". 4 October 2014. Retrieved 5 October 2014.
  29. "The Daily Telegraph". Telegraph.co.uk. 3 October 2014. Archived from the original on 4 October 2014. Retrieved 5 October 2014.
  30. Blackburn, D. G.; Flemming, A. F. (2011). "Invasive implantation and intimate placental associations in a placentotrophic African lizard, Trachylepis ivensi (scincidae)". Journal of Morphology. 273 (2): 137–59. doi:10.1002/jmor.11011. PMID   21956253. S2CID   5191828.
  31. Hugh Tyndale-Biscoe; Marilyn Renfree (30 January 1987). Reproductive Physiology of Marsupials. Cambridge University Press. ISBN   978-0-521-33792-2. Archived from the original on 10 April 2021. Retrieved 19 October 2020.
  32. Ronald M. Nowak (7 April 1999). Walker's Mammals of the World. JHU Press. ISBN   978-0-8018-5789-8. Archived from the original on 10 April 2021. Retrieved 4 September 2017.
  33. 1 2 Romer, Alfred Sherwood; Parsons, Thomas S. (1977). The Vertebrate Body. Philadelphia, Pennsylvania: Holt-Saunders International. pp. 390–392. ISBN   0-03-910284-X.
  34. Lewitus, Eric, and Christophe Soligo. "Life-history correlates of placental structure in eutherian evolution Archived 2017-09-06 at the Wayback Machine ." Evolutionary Biology 38.3 (2011): 287-305.
  35. Bernd Würsig; William F. Perrin; J.G.M. Thewissen (26 February 2009). Encyclopedia of Marine Mammals. Academic Press. ISBN   978-0-08-091993-5. Archived from the original on 10 April 2021. Retrieved 19 October 2020.