Editing Ovulation

{{Short description|Release of egg cells from the ovaries}}
{{infobox anatomy
| Name    = Ovulation
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| Caption = Following a surge of [[luteinizing hormone]] (LH), an [[oocyte]] (immature egg cell) will be released into the [[uterine tube]], where it will then be available to be fertilized by a male's sperm within 12 hours. Ovulation marks the end of the [[follicular phase]] of the [[ovarian cycle]], and the start of the [[luteal phase]].
| Width   = 250
}}
'''Ovulation''' is an important part of the [[menstrual cycle]] in female [[Vertebrate|vertebrates]] where the [[egg cells]] are released from the [[ovaries]] as part of the [[ovarian cycle]]. In female humans ovulation typically occurs near the midpoint in the menstrual cycle and after the [[follicular phase]]. Ovulation is stimulated by an increase in [[luteinizing hormone]] (LH). The [[ovarian follicle]]s rupture and release the secondary [[oocyte]] ovarian cells.<ref>{{Citation |last=Holesh |first=Julie E. |title=Physiology, Ovulation |date=2024 |work=StatPearls |url=https://www.ncbi.nlm.nih.gov/books/NBK441996/ |access-date=2024-11-20 |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=28723025 |last2=Bass |first2=Autumn N. |last3=Lord |first3=Megan}}</ref>    

After ovulation, during the [[luteal phase]], the egg will be available to be [[Human fertilization|fertilized]] by [[sperm]]. If it is not, it will break down in less than a day. Meanwhile, the [[uterus|uterine]] lining ([[endometrium]]) continues to thicken to be able to receive a [[fertilized egg]]. If no [[Fertilisation|conception]] occurs, the uterine lining will eventually break down and be shed from the body via the [[vagina]] during [[menstruation]].<ref>{{cite book| last = Young | first = Barbara | name-list-style = vanc |title=Wheater's Functional Histology: A Text and Colour Atlas |edition=5th |publisher=Elsevier Health Sciences |year=2006 |isbn=9780443068508 |page=359 |url= https://books.google.com/books?id=88tla60sHAUC&pg=PA359 |access-date=2013-11-09 }}</ref>

Some people choose to track ovulation in order to improve or aid becoming pregnant by timing intercourse with their ovulation.<ref name=":1">{{Cite web |last=CDC |date=2024-05-20 |title=Infertility: Frequently Asked Questions |url=https://www.cdc.gov/reproductive-health/infertility-faq/index.html |access-date=2024-11-20 |website=Reproductive Health |language=en-us}}</ref> The signs of ovulation may include [[Cervix|cervical mucus]] changes, mild [[Cramp|cramping]] in the abdominal area, and a small rise in [[basal body temperature]]. Medication is also sometimes required by those experiencing infertility to induce ovulation.<ref name=":1" />

== Process ==

[[File:Menstrual cycle.svg|thumb|right|350px|Ovulation occurs about midway through the [[menstrual cycle]], after the [[follicular phase]], and is followed by the [[luteal phase]]. Note that ovulation is characterized by a sharp spike in levels of [[luteinizing hormone]] (LH) and [[follicle-stimulating hormone]] (FSH), resulting from the peak of [[estrogen]] levels during the follicular phase.]]

Ovulation occurs about midway through the [[menstrual cycle]], after the [[follicular phase]]. The days in which a woman is most fertile can be calculated based on the date of the last menstrual period and the length of a typical menstrual cycle.<ref>{{Cite web|title=How to Chart Your Menstrual Cycle|url=https://www.webmd.com/baby/charting-your-fertility-cycle|access-date=2021-07-29|website=WebMD|language=en}}</ref> The few days surrounding ovulation (from approximately days 10 to 18 of a 28-day cycle), constitute the most fertile phase.<ref>{{cite book| vauthors = Chaudhuri SK |chapter=Natural Methods of Contraception|title=Practice of Fertility Control: A Comprehensive Manual, 7/e|publisher=Elsevier India|year=2007|isbn=9788131211502|page=49|chapter-url=https://books.google.com/books?id=pzanxKlcU74C&pg=PA49|access-date=2013-11-09}}</ref><ref>{{cite book| last = Allen | first = Denise | name-list-style = vanc |title=Managing Motherhood, Managing Risk: Fertility and Danger in West Central Tanzania |publisher=University of Michigan Press |year=2004 |isbn=9780472030279 |pages=[https://archive.org/details/unset0000unse_l1z7/page/132 132]–133 |url= https://archive.org/details/unset0000unse_l1z7 | url-access = registration |access-date=2013-11-09}}</ref><ref>{{cite book| last = Rosenthal | first = Martha | name-list-style = vanc |title=Human Sexuality: From Cells to Society|publisher=Cengage Learning|year=2012|isbn=9780618755714|page=322|url=https://books.google.com/books?id=d58z5hgQ2gsC&pg=PT322|access-date=2013-11-09}}</ref><ref>{{cite book|editor1=Nichter, Mark |editor2=Nichter, Mimi |title=Anthropology & International Health: South Asian Case Studies| last1 = Nichter | first1 = Mark | last2 = Nichter | first2 = Mimi | name-list-style = vanc |chapter=Cultural Notions of Fertility in South Asia and Their Influence on Sri Lankan Family Planning Practices |publisher=Psychology Press |year=1996 |isbn=9782884491716 |pages=8–11 |chapter-url=https://books.google.com/books?id=wWBEhhMPUUcC&pg=PA8 |access-date=2013-11-09}}</ref> The time from the beginning of the [[last menstrual period]] (LMP) until ovulation is, on average, 14.6 days, but with substantial variation among females and between cycles in any single female, with an overall 95% [[prediction interval]] of 8.2 to 20.5 days.<ref name="Geirsson2003">{{cite journal |vauthors=Geirsson RT |date=May 1991 |title=Ultrasound instead of last menstrual period as the basis of gestational age assignment |journal=Ultrasound in Obstetrics & Gynecology |volume=1 |issue=3 |pages=212–9 |doi=10.1046/j.1469-0705.1991.01030212.x |pmid=12797075 |s2cid=29063110}}</ref>

The process of ovulation is controlled by the [[hypothalamus]] of the brain and through the release of hormones secreted in the [[Anterior pituitary|anterior lobe]] of the [[pituitary gland]], [[luteinizing hormone]] (LH) and [[follicle-stimulating hormone]] (FSH).<ref name=Marieb>{{cite book | last = Marieb | first = Elaine | name-list-style = vanc | title = Anatomy & physiology | publisher = Benjamin-Cummings | page=915  | year = 2013 | isbn = 9780321887603 }}</ref> In the [[Follicular phase|preovulatory]] phase of the [[menstrual cycle]], the ovarian follicle will undergo a series of transformations called cumulus expansion, which is stimulated by FSH. After this is done, a hole called the [[Stigma (anatomy)|stigma]] will form in the [[Ovarian follicle|follicle]], and the secondary oocyte will leave the follicle through this hole. Ovulation is triggered by a spike in the  amount of FSH and LH released from the pituitary gland. During the [[luteal phase|luteal (post-ovulatory) phase]], the secondary oocyte will travel through the [[fallopian tubes]] toward the [[uterus]]. If [[fertilized]] by a [[sperm]], the fertilized secondary oocyte or ovum may [[Implantation (human embryo)|implant]] there 6–12 days later.<ref name="wilcox">{{cite journal | vauthors = Wilcox AJ, Baird DD, [[Clarice Weinberg|Weinberg CR]] | title = Time of implantation of the conceptus and loss of pregnancy | journal = The New England Journal of Medicine | volume = 340 | issue = 23 | pages = 1796–9 | date = June 1999 | pmid = 10362823 | doi = 10.1056/NEJM199906103402304 | doi-access = free }}</ref>

=== Follicular phase ===
{{See also|Folliculogenesis}}

The [[follicular phase]] (or proliferative phase) is the phase of the menstrual cycle during which the [[ovarian follicles]] mature. The follicular phase lasts from the beginning of [[menstruation]] to the start of ovulation.<ref>{{cite book| last1 = Littleton | first1 = Lynna A. | last2 = Engebretson | first2 = Joan C. | name-list-style = vanc |title=Maternity Nursing Care |publisher=Cengage Learning |isbn=9781401811921 |page=195 |url= https://books.google.com/books?id=nondhCqicAAC&pg=PA195 |access-date=2013-11-09 |date=2004-10-14}}</ref><ref>{{cite book| last = Gupta | first = Ramesh C. | name-list-style = vanc |title= Reproductive and Developmental Toxicology |publisher=Academic Press |year=2011 |isbn=9780123820334 |page=22 |url=https://books.google.com/books?id=jGHRR32wz5MC&pg=PA22 |access-date=2013-11-09 }}</ref>

For ovulation to be successful, the ovum must be supported by the [[Corona radiata (embryology)|corona radiata]] and [[cumulus oophorus|cumulus oophorous]] [[granulosa cell]]s.<ref>{{Cite web |date=2012 |title=Cumulus Oophorus - an overview |url=https://www.sciencedirect.com/topics/veterinary-science-and-veterinary-medicine/cumulus-oophorus |access-date=2023-05-22 |website=sciencedirect.com}}</ref> The latter undergo a period of proliferation and mucification known as cumulus expansion. Mucification is the secretion of a [[hyaluronic acid]]-rich cocktail that disperses and gathers the cumulus cell network in a sticky matrix around the ovum. This network stays with the ovum after ovulation and has been shown to be necessary for fertilization.<ref>{{Cite web|url=https://coveville.com/can-you-get-pregnant-after-ovulation/|title=Can You Get Pregnant after Ovulation?|website=coveville.com|access-date=3 Feb 2015|date=2015-02-03}}</ref><ref>{{cite web |url= http://www.medicalnewstoday.com/articles/296751.php |title= Fertilization: your pregnancy week by week|website=medicalnewstoday.com |access-date=15 Feb 2016 }}</ref>

=== Ovulation ===

[[Estrogen]] levels peak towards the end of the follicular phase, around 12 and 24 hours. This, by positive feedback, causes a surge in levels of [[luteinizing hormone]] (LH) and [[follicle-stimulating hormone]] (FSH). This lasts from 24 to 36 hours, and results in the rupture of the ovarian follicles, causing the oocyte to be released from the ovary.<ref>{{cite book| vauthors = Watson S, Stacy KM |chapter=The Endocrine System| veditors = McDowell J |title=Encyclopedia of Human Body Systems | volume = 1 |publisher=Greenwood |year=2010 |isbn=9780313391750 |pages=201–202 |chapter-url= https://books.google.com/books?id=7tt1C1aJ0G4C&pg=PA201 |access-date=2013-11-09}}</ref>

Through a signal transduction cascade initiated by LH, which activates the pro-inflammatory genes through cAMP secondary messenger, [[peptidase|proteolytic enzymes]] are secreted by the follicle that degrade the follicular tissue at the site of the blister, forming a hole called the ''stigma''. The [[secondary oocyte]] leaves the ruptured  follicle and moves out into the [[peritoneal cavity]] through the stigma, where it is caught by the [[Fimbria (female reproductive system)|fimbriae]] at the end of the [[fallopian tube]]. After entering the fallopian tube, the oocyte is pushed along by [[cilia]], beginning its journey toward the [[uterus]].<ref name=Marieb/>

By this time, the oocyte has completed [[meiosis|meiosis I]], yielding two cells: the larger [[ovum|secondary oocyte]] that contains all of the cytoplasmic material and a smaller, inactive first polar body. [[meiosis|Meiosis II]] follows at once but will be arrested in the [[metaphase]] and will so remain until fertilization. The [[spindle apparatus]] of the second meiotic division appears at the time of ovulation. If no fertilization occurs, the oocyte will degenerate between 12 and 24 hours after ovulation.<ref>{{cite journal | vauthors = Depares J, Ryder RE, Walker SM, Scanlon MF, Norman CM | title = Ovarian ultrasonography highlights precision of symptoms of ovulation as markers of ovulation | journal = British Medical Journal | volume = 292 | issue = 6535 | pages = 1562 | date = June 1986 | pmid = 3087519 | pmc = 1340563 | doi = 10.1136/bmj.292.6535.1562 }}</ref> Approximately 1–2% of ovulations release more than one oocyte. This tendency increases with maternal age. Fertilization of two different oocytes by two different spermatozoa results in fraternal twins.<ref name=Marieb/>

The precise moment of ovulation was captured on film for the first time in 2008, coincidentally, during a routine hysterectomy procedure. According to the attending gynecologist, the ovum's emergence and subsequent release from the ovarian follicle occurred within a 15-minute timeframe. <ref>{{cite news |url=http://news.bbc.co.uk/2/hi/health/7447942.stm |title=Ovulation moment caught on camera |date=2008-06-12 |publisher=BBC News}}</ref>

=== Luteal phase ===
{{Main|Luteal phase}}

The follicle proper has met  the end of its lifespan. Without the oocyte, the follicle folds inward on  itself, transforming into the [[corpus luteum]] (pl. corpora lutea), a  steroidogenic cluster of cells that produces [[estrogen]] and [[progesterone]]. These hormones induce the  endometrial glands to begin production of the [[endometrium|proliferative endometrium]] and later  into [[endometrium|secretory endometrium]], the site of embryonic growth if implantation occurs. The action of progesterone increases [[basal body temperature]] by one-quarter to one-half degree Celsius (one-half to one degree Fahrenheit).  The corpus luteum continues this [[paracrine]]  action for the remainder of the menstrual cycle, maintaining the endometrium, before disintegrating into scar tissue during menses.<ref>{{cite news|title=Usually, it occurs between the 10th and 20th day of your menstrual cycle|url=http://www.momjunction.com/ovulation-calculator/|access-date=26 July 2016|work=momjunction}}</ref>

==Clinical presentation==
{{further|Concealed ovulation|Fertility  awareness|Mittelschmerz}}
The start of ovulation may be detected by signs that are not readily discernible other than to the ovulating female herself, thus humans are said to have a [[concealed ovulation]].<ref>{{Cite web |last1=Smith |first1=Yolanda |last2=Pharm |first2=B. |date=2010-04-27 |title=Ovulation Signs |url=https://www.news-medical.net/health/Ovulation-Signs.aspx |access-date=2023-05-22 |website=News-Medical.net |language=en}}</ref> In many animal species there are distinctive signals indicating the period when the female is fertile. Several explanations have been proposed to explain concealed ovulation in humans.

Females near ovulation experience changes in the [[Cervix#Cervical mucus|cervical mucus]], and in [[basal body temperature]]. Furthermore, many females experience secondary fertility signs including [[Mittelschmerz]] (pain associated with ovulation) and a heightened sense of [[olfaction|smell]], and can sense the precise moment of ovulation.<ref name="pmid12853171">{{cite journal | vauthors = Navarrete-Palacios E, Hudson R, Reyes-Guerrero G, Guevara-Guzmán R | title = Lower olfactory threshold during the ovulatory phase of the menstrual cycle | journal = Biological Psychology | volume = 63 | issue = 3 | pages = 269–79 | date = July 2003 | pmid = 12853171 | doi = 10.1016/S0301-0511(03)00076-0 | s2cid = 46065468 | doi-access = free }}</ref><ref>{{cite book|editor=Beckmann, Charles R.B.|title=Obstetrics and Gynecology|publisher=Lippincott Williams & Wilkins|year=2010|isbn=9780781788076|pages=306–307|url=https://books.google.com/books?id=0flWgd3OJLEC&pg=PA306|access-date=2013-11-09}}</ref> However, midcycle pain may also not be due to Mittelschmerz, but due to other factors such as cysts, endometriosis, sexually transmitted infections, or an ectopic pregnancy.<ref>{{Cite web|title=Ovulation Pain: Symptoms, Causes & Pain Relief|url=https://my.clevelandclinic.org/health/diseases/9134-ovulation-pain-mittelschmerz|access-date=2021-07-29|website=Cleveland Clinic}}</ref> Other possible signs of ovulation include tender breasts, bloating, and cramps, although these symptoms are not a guarantee that ovulation is taking place.<ref>{{Cite web|title=Am I Ovulating? How to Spot the Signs|url=https://www.webmd.com/baby/am-i-ovulating|access-date=2021-07-29|website=WebMD|language=en}}</ref><ref>{{Cite web|date=2020-06-18|title=Ovulation cramps: Symptoms and what they mean for fertility|url=https://www.medicalnewstoday.com/articles/ovulation-cramps|access-date=2021-07-29|website=www.medicalnewstoday.com|language=en}}</ref>

Many females experience heightened sexual desire in the several days immediately before ovulation.<ref name="pmid15216427">{{cite journal | vauthors = Bullivant SB, Sellergren SA, Stern K, Spencer NA, Jacob S, Mennella JA, McClintock MK | title = Women's sexual experience during the menstrual cycle: identification of the sexual phase by noninvasive measurement of luteinizing hormone | journal = Journal of Sex Research | volume = 41 | issue = 1 | pages = 82–93 | date = February 2004 | pmid = 15216427 | doi = 10.1080/00224490409552216 | s2cid = 40401379 }}</ref> One study concluded that females subtly improve their facial  attractiveness during ovulation.<ref>{{cite journal |vauthors=Roberts S, Havlicek J, Flegr J, Hruskova M, Little A, Jones B, Perrett D, Petrie M | title =  Female facial attractiveness increases during the fertile phase of the menstrual cycle | journal = Proc Biol Sci | volume = 271  | issue  = Suppl 5:S | pages = 270–2 | date=August 2004 | pmid =  15503991 | doi = 10.1098/rsbl.2004.0174 | pmc=1810066}}</ref>

[[File:Pregnancy chance by day near ovulation.jpg|thumb|Chance of [[human fertilization|fertilization]] by day relative to ovulation<ref name="DunsonBaird1999">{{cite journal | vauthors = Dunson DB, Baird DD, Wilcox AJ, [[Clarice Weinberg|Weinberg CR]] | title = Day-specific probabilities of clinical pregnancy based on two studies with imperfect measures of ovulation | journal = Human Reproduction | volume = 14 | issue = 7 | pages = 1835–9 | date = July 1999 | pmid = 10402400 | doi = 10.1093/humrep/14.7.1835 | doi-access = free }}</ref>]]
Symptoms related to the onset of ovulation, the moment of ovulation and the body's process of beginning and ending the menstrual cycle vary in intensity with each female but are fundamentally the same. The charting of such symptoms &mdash; primarily basal body temperature, mittelschmerz and cervical position &mdash; is referred to as the sympto-thermal method of fertility awareness, which allow auto-diagnosis by a female of her state of ovulation. Once training has been given by a suitable authority, fertility charts can be completed on a cycle-by-cycle basis to show ovulation. This gives the possibility of using the data to predict fertility for natural contraception and pregnancy planning.

Urine levels of the [[hormone]] pregnanediol 3-glucuronide of over 5 μg/mL has been used to confirm ovulation. This test has a 100% specificity over 107 women.<ref>{{Cite journal |last1=Ecochard |first1=R. |last2=Leiva |first2=R. |last3=Bouchard |first3=T. |last4=Boehringer |first4=H. |last5=Direito |first5=A. |last6=Mariani |first6=A. |last7=Fehring |first7=R. |date=2013-10-01 |title=Use of urinary pregnanediol 3-glucuronide to confirm ovulation |url=https://epublications.marquette.edu/cgi/viewcontent.cgi?article=1492&context=nursing_fac |journal=Steroids |language=en |volume=78 |issue=10 |pages=1035–1040 |doi=10.1016/j.steroids.2013.06.006 |pmid=23831784 |s2cid=20604171 |issn=0039-128X}}</ref>

== Disorders ==
Disorders of ovulation, also known as '''ovulatory disorders''' are classified as [[menstrual disorder]]s and include oligoovulation (infrequent or irregular ovulation) and anovulation (absence of ovulation):<ref name="MUKHERJIGANGULYSEAL">{{cite book | author1 = JOYDEV MUKHERJI | author2 = RAJENDRA PRASAD GANGULY | author3 = SUBRATA LALL SEAL | title = BASICS OF GYNECOLOGY FOR EXAMINEES: ALL IN ONE : THEORY, CLINICS & CASE DISCUSSION, INSTRUMENTS AND SPECIMENS, OPERATIVE GYNECOLOGY AND RADIOLOGY (X-RAY, USG INCLUDING 3D) | publisher = Academic Publishers | pages = 244– | isbn = 9789387162303 | url = https://books.google.com/books?id=LqCmDwAAQBAJ&pg=PA244}}</ref>

* Oligoovulation is infrequent or irregular ovulation (usually defined as cycles of greater than 36 days or fewer than 8 cycles a year)
* [[Anovulation]] is absence of ovulation when it would be normally expected (in a post-[[menarche|menarchal]], premenopausal female).  Anovulation usually manifests itself as irregularity of menstrual periods, that is, unpredictable variability of intervals, duration, or bleeding. Anovulation can also cause cessation of periods (secondary amenorrhea) or excessive bleeding ([[dysfunctional uterine bleeding]]).

The [[World Health Organization]] (WHO) has developed the following classification of ovulatory disorders:<ref>[https://books.google.com/books?id=fh2hJDiLOyAC&pg=PA54 Page 54] in: {{cite book | first1 = Enda | last1 = McVeigh | first2 = John | last2 = Guillebaud | first3 = Roy | last3 = Homburg | name-list-style = vanc |title=Oxford handbook of reproductive medicine and family planning |publisher=Oxford University Press |location=Oxford [Oxfordshire] |year=2008 |isbn=978-0-19-920380-2 }}</ref>

* WHO group I: [[Hypothalamic–pituitary–gonadal axis]] failure
* WHO group II: Hypothalamic–pituitary–gonadal axis dysfunction. WHO group II is the most common cause of ovulatory disorders, and the most common causative member is [[polycystic ovary syndrome]] (PCOS).<ref>{{cite journal | title = Health and fertility in World Health Organization group 2 anovulatory women | journal = Human Reproduction Update | volume = 18 | issue = 5 | pages = 586–99 | year = 2012 | pmid = 22611175 | doi = 10.1093/humupd/dms019 | doi-access =  | last1 = Baird | first1 = D. T. | last2 = Balen | first2 = A. | last3 = Escobar-Morreale | first3 = H. F. | last4 = Evers | first4 = J. L. H. | last5 = Fauser | first5 = B. C. J. M. | last6 = Franks | first6 = S. | last7 = Glasier | first7 = A. | last8 = Homburg | first8 = R. | last9 = La Vecchia | first9 = C. | last10 = Devroey | first10 = P. | last11 = Diedrich | first11 = K. | last12 = Fraser | first12 = L. | last13 = Gianaroli | first13 = L. | last14 = Liebaers | first14 = I. | last15 = Sunde | first15 = A. | last16 = Tapanainen | first16 = J. S. | last17 = Tarlatzis | first17 = B. | last18 = Van Steirteghem | first18 = A. | last19 = Veiga | first19 = A. | last20 = Crosignani | first20 = P. G. | last21 = Evers | first21 = J. L. H. }}</ref>
* WHO group III: [[Ovarian failure]]
* WHO group IV: [[Hyperprolactinemia]]

[[Menstrual disorder]]s can often indicate ovulatory disorder.<ref name="Seli2011">{{cite book | editor = Emre Seli | date = 2 February 2011 | title = Infertility | publisher = John Wiley & Sons | pages = | isbn = 978-1-4443-9394-1 | oclc = 1083163793 | url = https://books.google.com/books?id=avCA9eCuAc8C&pg=PT35}}</ref>

==Ovulation induction==
{{Main|Ovulation induction}}
Ovulation  induction is a promising [[assisted reproductive technology]] for patients with conditions such as [[polycystic ovary syndrome]] (PCOS)  and [[oligomenorrhea]]. It is also used in [[in vitro fertilization]] to make the follicles mature before [[egg retrieval]]. Usually, [[Controlled ovarian hyperstimulation|ovarian stimulation]] is used in conjunction with [[ovulation induction]] to stimulate the formation of multiple oocytes.<ref name=ivf.com/> Some sources<ref name=ivf.com/> include ovulation induction in the definition of ''ovarian stimulation''.

A low dose of [[human chorionic gonadotropin]] (HCG) may be injected after completed ovarian stimulation. Ovulation will occur between 24 and 36 hours after the HCG injection.<ref name=ivf.com>[http://www.ivf.com/ovind.html IVF.com > Ovulation Induction] {{Webarchive|url=https://web.archive.org/web/20120226141802/http://www.ivf.com/ovind.html |date=2012-02-26 }} Retrieved on Mars 7, 2010</ref>

By contrast, [[Induced ovulation (animals)|induced ovulation]] in some animal species occurs naturally, ovulation can be stimulated by coitus.<ref>{{cite journal | vauthors = Bakker J, Baum MJ | title = Neuroendocrine regulation of GnRH release in induced ovulators | journal = Frontiers in Neuroendocrinology | volume = 21 | issue = 3 | pages = 220–62 | date = July 2000 | pmid = 10882541 | doi = 10.1006/frne.2000.0198 | hdl = 2268/91368 | s2cid = 873489 | url = http://orbi.ulg.ac.be/handle/2268/91368 | hdl-access = free }}</ref>

==Ovulation suppression==
[[Combined hormonal contraceptive]]s inhibit [[follicular phase|follicular development]] and prevent ovulation as a primary mechanism of action.<ref name="Nelson 2011">{{cite book| last1 = Nelson| first1 = Anita L.| last2 = Cwiak| first2 = Carrie| editor1-last = Hatcher| editor1-first = Robert A.| editor2-last = Trussell| editor2-first = James| editor3-last = Nelson| editor3-first = Anita L.| editor4-last = Cates| editor4-first = Willard | editor5-last = Kowal| editor5-first = Deborah| editor6-last = Policar| editor6-first = Michael S. | name-list-style = vanc | title = Contraceptive technology| edition = 20th revised| year = 2011| publisher = Ardent Media| location = New York| isbn = 978-1-59708-004-0| oclc = 781956734| pages = 249–341| chapter = Combined oral contraceptives (COCs)| issn = 0091-9721 }} pp. 257–258</ref> The ''ovulation-inhibiting dose'' (OID) of an [[estrogen (medication)|estrogen]] or [[progestogen]] refers to the dose required to consistently inhibit ovulation in women.<ref name="pmid22078182">{{cite journal | vauthors = Endrikat J, Gerlinger C, Richard S, Rosenbaum P, Düsterberg B | title = Ovulation inhibition doses of progestins: a systematic review of the available literature and of marketed preparations worldwide | journal = Contraception | volume = 84 | issue = 6 | pages = 549–57 | date = December 2011 | pmid = 22078182 | doi = 10.1016/j.contraception.2011.04.009 }}</ref> Ovulation inhibition is an [[antigonadotropic]] effect and is mediated by inhibition of the secretion of the [[gonadotropin]]s, LH and FSH, from the pituitary gland.

In [[assisted reproductive technology]] including [[in vitro fertilization]], cycles where a [[transvaginal oocyte retrieval]] is planned generally necessitates ovulation suppression, because it is not practically feasible to collect oocytes after ovulation. For this purpose, ovulation can be suppressed by either a [[GnRH agonist]] or a [[GnRH antagonist]], with different protocols depending on which substance is used. {{further|Suppression of spontaneous ovulation in ovarian hyperstimulation}}

== Fertility and timing of ovulation ==
Most women who are able to conceive are fertile for an estimated five days before ovulation and one day after ovulation.<ref name=":0">{{Cite journal |last1=Gibbons |first1=Tatjana |last2=Reavey |first2=Jane |last3=Georgiou |first3=Ektoras X |last4=Becker |first4=Christian M |date=2023-09-15 |editor-last=Cochrane Gynaecology and Fertility Group |title=Timed intercourse for couples trying to conceive |journal=Cochrane Database of Systematic Reviews |language=en |volume=2023 |issue=9 |pages=CD011345 |doi=10.1002/14651858.CD011345.pub3 |pmc= 10501857|pmid=37709293 }}</ref> There is some evidence that for couples who have been trying to conceive a child for less than 12 months, and the female is under 40 years old, practicing timed intercourse (timing intercourse with ovulation using urine tests that predict ovulation) may help improve the rate of pregnancy and live births.<ref name=":0" /> The role that stress plays in ovulation, fertility, and understanding the biological basis for stress-induced anovulation and the role of cortisol is not entirely clear.<ref>{{Cite journal |last1=Karunyam |first1=Bheena Vyshali |last2=Abdul Karim |first2=Abdul Kadir |last3=Naina Mohamed |first3=Isa |last4=Ugusman |first4=Azizah |last5=Mohamed |first5=Wael M. Y. |last6=Faizal |first6=Ahmad Mohd |last7=Abu |first7=Muhammad Azrai |last8=Kumar |first8=Jaya |date=2023 |title=Infertility and cortisol: a systematic review |journal=Frontiers in Endocrinology |volume=14 |pages=1147306 |doi=10.3389/fendo.2023.1147306 |issn=1664-2392 |pmc=10344356 |pmid=37455908 |doi-access=free }}</ref>

== See also ==
*[[Anovulatory cycle]]
*[[Corpus luteum]]
*[[Folliculogenesis]]
*[[Menstrual cycle]]
*[[Oogenesis]]
*[[Mittelschmerz]]
*[[Fertilisation]]

==Notes==
{{Reflist|32em}}

== Further reading ==
{{refbegin|32em}}
* {{cite journal | vauthors = Baerwald AR, Adams GP, Pierson RA | title = A new model for ovarian follicular development during the human menstrual cycle | journal = Fertility and Sterility | volume = 80 | issue = 1 | pages = 116–22 | date = July 2003 | pmid = 12849812 | doi = 10.1016/S0015-0282(03)00544-2 | url = http://www.fertstert.org/article/S0015-0282(03)00544-2/abstract | doi-access = free }}
* {{cite journal | vauthors = Chabbert Buffet N, Djakoure C, Maitre SC, Bouchard P | title = Regulation of the human menstrual cycle | journal = Frontiers in Neuroendocrinology | volume = 19 | issue = 3 | pages = 151–86 | date = July 1998 | pmid = 9665835 | doi = 10.1006/frne.1998.0167 | s2cid = 40594356 }}
* {{cite journal | vauthors = Fortune JE | title = Ovarian follicular growth and development in mammals | journal = Biology of Reproduction | volume = 50 | issue = 2 | pages = 225–32 | date = February 1994 | pmid = 8142540 | doi = 10.1095/biolreprod50.2.225 | doi-access = free }}
* {{cite journal | vauthors = Guraya SS, Dhanju CK | title = Mechanism of ovulation--an overview | journal = Indian Journal of Experimental Biology | volume = 30 | issue = 11 | pages = 958–67 | date = November 1992 | pmid = 1293040 }}
* {{cite book| vauthors = Klowden MJ |chapter=Oviposition Behavior| veditors = Resh VH, Carde RT |title=Encyclopedia of Insects|publisher=Academic Press|year=2009|isbn=9780080920900|chapter-url=https://books.google.com/books?id=Jk0Hym1yF0cC&pg=PA745|access-date=2013-11-09}}
* {{cite book | last1= Motwani | first1= Rohini |last2= Krishna |first2= Hare | title= Encyclopedia of Sexual Psychology and Behavior | date= 2024 | publisher= [[Springer, Cham]] | isbn= 978-3-031-08956-5 |pages = 1–6 | url = https://link.springer.com/referenceworkentry/10.1007/978-3-031-08956-5_302-1 | language = en | chapter = Ovulation | doi= 10.1007/978-3-031-08956-5_302-1}}
* {{cite journal | vauthors = Su HW, Yi YC, Wei TY, Chang TC, Cheng CM | title = Detection of ovulation, a review of currently available methods | journal = Bioengineering & Translational Medicine | volume = 2 | issue = 3 | pages = 238–246 | date = September 2017 | pmid = 29313033 | pmc = 5689497 | doi = 10.1002/btm2.10058 }}
* {{cite journal |last1=Ziomkiewicz |first1=Anna |title=Ovulation |journal=The International Encyclopedia of Human Sexuality |date=2015 |pages=831–860 |doi=10.1002/9781118896877.wbiehs324}}
{{refend}}

== External links  ==
*[https://www.newscientist.com/article/mg19826604-200-human-egg-makes-accidental-debut-on-camera/ Human egg makes accidental debut on camera]
*[http://news.bbc.co.uk/2/hi/health/7447942.stm  Ovulation moment caught on camera]

{{Reproductive  physiology}}
{{Menstrual cycle}}
{{Eggs}}
{{Authority control}}

[[Category:Menstrual cycle]]
[[Category:Human reproduction]]
[[Category:Midwifery]]
[[Category:Human female endocrine system]]
[[Category:Theriogenology]]