# Decidua > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Decidua > Markdown URL: https://mediated.wiki/source/Decidua.md > Source: https://en.wikipedia.org/wiki/Decidua > Source revision: 1343941420 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) The **decidua** is the modified [mucosal lining](/source/Mucous_membrane) of the [uterus](/source/Uterus) (that is, modified [endometrium](/source/Endometrium)) that forms every month, in preparation for [pregnancy](/source/Pregnancy). It is shed off each month when there is no fertilized egg to support.[1] The decidua is under the influence of [progesterone](/source/Progesterone). Endometrial cells become highly characteristic. The decidua forms the maternal part of the [placenta](/source/Placenta) and remains for the duration of the pregnancy. After birth the decidua is shed together with the placenta.[1] ## Structure The part of the decidua that interacts with the [trophoblast](/source/Trophoblast) is the ***decidua basalis*** (also called ***decidua placentalis***), while the ***decidua capsularis*** grows over the [embryo](/source/Embryo) on the luminal side, enclosing it into the endometrium. The remainder of the decidua is termed the ***decidua parietalis*** or ***decidua vera***, and it will fuse with the decidua capsularis by the fourth month of gestation. Three morphologically distinct layers of the decidua basalis can then be described: - Compact outer layer (***stratum compactum***) - Intermediate layer (***stratum spongiosum***) - Boundary layer adjacent to the [myometrium](/source/Myometrium) (***stratum basalis***) Within the decidua, occasional fibrinoid deposits form where the syncytiotrophoblast is damaged. The region of fibrinoid deposition where trophoblasts meet the compact portion of the decidua basalis is called ***Rohr's layer***, while the fibrinoid deposits that occur between the compact and spongy layer of the decidua basalis is termed **Nitabuch's layer** (for [Raissa Nitabuch](/source/Raissa_Nitabuch)). This layer is absent in [placenta accreta](/source/Placenta_accreta).[2] The decidua has a [histologically](/source/Histology)-distinct appearance, displaying large polygonal [decidual cells](/source/Decidual_cells) in the stroma. These are enlarged endometrial stromal cells, which resemble [epithelium](/source/Epithelium) (and are referred to as "epithelioid"). [Decidualization](/source/Decidualization) includes the process of differentiation of the spindle-shape stromal fibroblasts into the plump secretory decidual cells, which create a pericellular extracellular matrix rich in [fibronectin](/source/Fibronectin) and [laminin](/source/Laminin) (similar to epithelial cells). Vascularity, as well as vascular permeability, is enhanced in the decidualizing endometrium. Its [leukocyte](/source/Leukocyte) population is distinct, with the presence of large endometrial granular leukocytes being predominant, while polynuclear leukocytes and [B cells](/source/B_cell) are scant. The large granular lymphocytes ([CD56](/source/Neural_cell_adhesion_molecule) bright) are called [uterine natural killer cells](/source/Uterine_natural_killer_cells) (uNK cells). ## Development After [ovulation](/source/Ovulation), in [placental mammals](/source/Placental_mammal), the endometrial lining becomes hypertrophic and vascular under the influence of the [sex hormones](/source/Sex_hormone), [estrogen](/source/Estrogen) and [progesterone](/source/Progesterone). In animals exhibiting [hemochorial placentation](/source/Hemochorial_placentation), the endometrium undergoes [decidualization](/source/Decidualization) following [implantation](/source/Implantation_(human_embryo)). If implantation does not occur, the secretory lining will be absorbed ([estrous cycle](/source/Estrous_cycle)) or shed ([menstrual cycle](/source/Menstrual_cycle)). The decidua is shed with the placenta during [birth](/source/Birth). ## Function As the maternal interface to the embryo the decidua participates in the exchanges of nutrition, gas, and waste with the gestation. It also protects the pregnancy from the maternal [immune system](/source/Immune_system). Further, the decidua has to allow a very controlled invasion of the trophoblast. In invasive placental disorders like [placenta accreta](/source/Placenta_accreta) decidualization have been consistently found to be deficient. ### Hormone production The decidua secretes [hormones](/source/Hormones), [growth factors](/source/Growth_factor), and [cytokines](/source/Cytokine). It has receptors for [estrogen](/source/Estrogen), [progesterone](/source/Progesterone), [growth hormone](/source/Growth_hormone), and others. Among its products are hormones commonly associated with other organs such as [cortisol](/source/Cortisol), [CRF](/source/Corticotropin-releasing_hormone), [GnRH](/source/GnRH), [prolactin](/source/Prolactin), and [relaxin](/source/Relaxin). Decidual prolactin is not under [dopaminergic](/source/Dopamine) control. [Insulin-like growth factor-binding protein 1](/source/Insulin-like_growth_factor-binding_protein_1) (IGFBP1) also called placental protein 12, and [PAEP](/source/PAEP) (glycodelin) appear to be specific products of the secretory and decidual lining. Other factors released include [interleukin-15](/source/Interleukin-15) and [vascular endothelial growth factor](/source/Vascular_endothelial_growth_factor) (VEGF). A reasonable understanding of the role and interplay of these hormones and factors has not been evolved. ### Other - In case of an [ectopic pregnancy](/source/Ectopic_pregnancy), the endometrium nevertheless becomes decidualized. A woman may shed the lining in the form of a [decidual cast](/source/Decidual_cast), which may be mistaken as a [miscarriage](/source/Miscarriage), when, in fact, the ectopic pregnancy still persists. - A [decidual reaction](/source/Decidual_reaction) can be observed in tissue of the [peritoneum](/source/Peritoneum) and [ovary](/source/Ovary) during a pregnancy, and represents a response of [stromal](/source/Stromal) tissue to [progesterone](/source/Progesterone). - Decidua in a [lymph node](/source/Lymph_node) may mimic [metastatic](/source/Metastasis) [carcinoma](/source/Carcinoma).[3] ## Clinical significance A long-lasting [infection](/source/Infection) of the decidua, [chronic deciduitis](/source/Chronic_deciduitis), is associated with [pre-term labour](/source/Preterm_birth).[4] ## Etymology The word comes . ## References 1. ["Definition of DECIDUA"](https://www.merriam-webster.com/dictionary/decidua). *www.merriam-webster.com*. Retrieved 25 October 2022. 1. Cunningham, F. Gary (ed.) (2005). *Williams obstetrics*. 22nd ed. New York; Toronto: McGraw-Hill Professional. ISBN 9780071413152. 1. Wu, DC.; Hirschowitz, S.; Natarajan, S. (May 2005). "Ectopic decidua of pelvic lymph nodes: a potential diagnostic pitfall". *Arch Pathol Lab Med*. **129** (5): e117–20. [doi:10.5858/2005-129-e117-EDOPLN](https://doi.org/10.5858/2005-129-e117-EDOPLN). [PMID 15859655](https://pubmed.ncbi.nlm.nih.gov/15859655) 1. Edmondson, N.; Bocking, A.; Machin, G.; Rizek, R.; Watson, C.; Keating, S. (2009). "The prevalence of chronic deciduitis in cases of preterm labor without clinical chorioamnionitis". *Pediatr Dev Pathol*. **12** (1): 16–21. [doi:10.2350/07-04-0270.1](https://doi.org/10.2350/07-04-0270.1). [PMID 18171100](https://pubmed.ncbi.nlm.nih.gov/18171100). [S2CID 25693917](https://api.semanticscholar.org/CorpusID:25693917) ## External links - [Histologic picture at med.utah.edu](http://www-medlib.med.utah.edu/WebPath/PLACHTML/PLAC094.html) --- Adapted from the Wikipedia article [Decidua](https://en.wikipedia.org/wiki/Decidua) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Decidua?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.