Menstrual Cycle

Aka: Menstrual Cycle, Follicular Phase, Proliferative Phase, Ovulatory Phase, Fertile Period, Luteal Phase

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II. Images

  1. menstrualCycle.png

III. Physiology: Background

  1. Menarche onset in girls (age <11 to 15 years)
    1. Menses onset after FSH and LH reach sufficient levels
  2. Oral Contraceptives (OCP) have a paradoxical effect on the Menstrual Cycle, Ovulation and fertility
    1. During a normal cycle, FSH triggers a dominant follicle to increase Estrogen, LH surge and Progesterone
    2. However chronically high Estrogen and Progesterone (e.g. OCP) inihibit Ovulation and fertilization
      1. Persistent Estrogen inhibits FSH and LH (resulting in no LH surge or Ovulation)
      2. Persistent Progesterone thickens Cervical Mucus and atrophies the uterine lining

IV. Physiology: Follicular Phase (Proliferative Phase in Early Cycle, Days 1 to 13 of cycle)

  1. Follicle Stimulating Hormone (FSH) stimulates ovary
    1. Group of ovarian follicles enlarge, of which one will be dominant, while the other follicles degenerate
    2. Dominant ovarian follicle emerges days 5-7 of cycle, increasing in size to 2 cm
      1. Vascularity doubles for dominant follicle
      2. Twin Gestation prone women generate 2 dominant follicles
      3. Dominant ovarian follicle produces Estrogen
      4. Dominant ovarian follicle also contains the ovum which will later be released during Ovulation
  2. Endometrium proliferative of glands and stroma
  3. Mean Duration: 10.8 days
  4. Hormones low
    1. Follicle Stimulating Hormone (FSH) low but rising
    2. Luteinizing Hormone (LH) low but rising
    3. Progesterone remains low

V. Physiology: Ovulatory Phase (Mid-Cycle)

  1. Hormone Surge
    1. Follicle Stimulating Hormone (FSH) with small surge
      1. Dominant ovarian follicle maturation is dependent on FSH stimulation
      2. Dominant ovarian follicle increases Estrogen release as it matures
    2. Estrogen rapidly peaks Days 10-15, then decreases
      1. Estrogen increases with dominant ovarian follicle maturation
      2. Rising Estrogen triggers a significant increase in LH (and to a lesser extent FSH)
        1. GnRH is released from Hypothalamus in pulses, in response to rising Estrogen
        2. GnRH stimulates pituitary LH and FSH release
        3. Contrast with chronically elevated Estrogen which suppresses LH and FSH release
        4. LH and FSH may be artificially stimulated in Female Infertility (e.g. Clomiphene)
    3. Luteinizing Hormone (LH) large surge
      1. Stimulates Ovulation (2 days after start of surge)
        1. Typically on day 14 of a 28 day cycle
        2. Occurs 14 days before Menstruation regardless of cycle length
      2. Stimulates corpus luteum
        1. Start of Progesterone increase, with endometrial secretory gland development
  2. Mid-cycle Symptoms Include
    1. Spotting
    2. Increased vaginal secretions
    3. Increased libido
    4. Nausea
    5. Abdominal Pain (Mittelschmerz)
  3. Identification of Ovulation Timing
    1. See Ovulation
    2. See Fertility Tracking
    3. See Basal Body Temperature
  4. Fertilization (pregnancy)
    1. Ovum (egg) fertilized typically within one day of Ovulation
    2. Sperm (viable for 1 to 3 days after intercourse) typically fertilizes the egg in the fallopian tube
    3. Fertilized egg exits the fallopian tube into the Uterus within 3-4 days after fertilization
      1. Ectopic Pregnancy may occur if the fertilized egg fails to reach the Uterus
    4. Fertilized egg implants within the endometrium 3-5 days after reaching the Uterus
      1. Implantation occurs 8 to 10 days after Ovulation
    5. Human Chorionic Gonadotropin (HCG) production starts on endometrial implantation
      1. See Pregnancy Test (Human Chorionic Gonadotropin)
      2. HCG (via an LH-like effect) maintains the corpus luteum
      3. Corpus luteum continues to produce Estrogen and Progesterone
      4. Estrogen and Progesterone maintain the endometrial lining and prevent sloughing
    6. Placenta develops from a combination of maternal and Embryonic tissue
      1. Also produces Estrogen and Progesterone

VI. Physiology: Luteal Phase (Secretory phase in Late Cycle)

  1. Endometrium with secretory gland development (stimulated by Progesterone)
    1. Prepares uterine endometrium for implantation (should an ovum be fertilized)
  2. Mean Duration: 13.3 days
  3. Hormonal changes: Ovum fertilization does not occur
    1. Estrogen continues to be high days 16-24
    2. Progesterone surges and remains until days 16-24
      1. Progesterone depletes Estrogen receptors
      2. Progesterone level falls to 0 at end of cycle
      3. Bleeding from Progesterone withdrawal occurs
    3. Increased Estrogen and Progesterone (as well as Inhibin) decrease FSH and LH via negative feedback
      1. Luteinizing Hormone (LH) returns to normal
      2. Follicle Stimulating Hormone (FSH) returns to normal
      3. Corpus luteum degenerates

VII. Physiology: Menstrual Phase (Bleeding)

  1. Corpus luteum degenerates
    1. Estrogen and Progesterone withdrawal
    2. Sloughing of endometrium with Menstrual Bleeding
      1. Fibrinolysin secreted by endometrium prevents menstrual blood from clotting
  2. LH and FSH start to increase again
    1. LH and FSH are no longer suppressed by Estrogen and Progesterone (via negative feedback)
    2. Starts a new Menstrual Cycle
    3. New group of ovarian follicles begins to develop
  3. Menopause
    1. Primordial follicles decrease over time, from Menarche, and eventually resulting in Menopause
    2. Estrogen and Progesterone production decreases as Menopause approaches
  4. Normal Menstrual Bleeding per cycle
    1. See Menses
    2. Duration: 2-8 days (mean: 4 days)
    3. Blood Loss: 20-80 ml (mean 35 ml), 13 mg iron loss
    4. Intervals: 21-35 days (mean 28 days)

VIII. References

  1. Goldberg (2014) Clinical Physiology, Medmasters, Miami, p. 143-5
  2. Guyton and Hall (2006) Medical Physiology, Elsevier Saunders, p. 1012-5

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Related Studies

Ontology: Fertile Period (C0015894)

Definition (MSH) The period in the MENSTRUAL CYCLE that is optimal for FERTILIZATION of the OVUM and yielding PREGNANCY. The duration of fertile period depends on the life span of male GAMETES within the female reproductive tract and the time of OVULATION. It usually begins a few days before ovulation and ends on the day of ovulation.
Concepts Temporal Concept (T079)
MSH D046910
French Période féconde, Période fertile, Période de fécondité, Période de fécondabilité, Période de fertilité
Swedish Fertilperiod
Czech plodné dny
Finnish Hedelmällinen vaihe
Russian FERTIL'NYI PERIOD, DETORODNYI PERIOD, ДЕТОРОДНЫЙ ПЕРИОД, ФЕРТИЛЬНЫЙ ПЕРИОД
English fertile period, fertile periods, Fertile Period
Spanish Periodo Fértil
Polish Okres płodności
German Fruchtbarkeitsphase im Menstruationszyklus
Italian Periodo fertile
Dutch Periode, vruchtbare, Vruchtbare periode
Portuguese Período Fértil
Derived from the NIH UMLS (Unified Medical Language System)

Ontology: Menstrual cycle, proliferative phase (C0016434)

Definition (MSH) The period of the MENSTRUAL CYCLE representing follicular growth, increase in ovarian estrogen (ESTROGENS) production, and epithelial proliferation of the ENDOMETRIUM. Follicular phase begins with the onset of MENSTRUATION and ends with OVULATION.
Concepts Temporal Concept (T079)
MSH D005498
English Follicular Phase, Menstrual Cycle, Follicular Phase, Menstrual Proliferative Phase, Phase, Follicular, Phase, Menstrual Proliferative, Phase, Preovulatory, Preovulatory Phase, Proliferative Phase, Menstrual, follicular phase, Menstrual Cycle, Proliferative Phase, Menstrual cycle, proliferative phase
Swedish Follikulär fas
Czech folikulární fáze
Finnish Munarakkulavaihe
French Phase folliculaire du cycle menstruel, Phase proliférative du cycle menstruel, Phase préovulatoire, Phase pré-ovulatoire, Phase folliculaire
Russian PREOVULIATORNAIA FAZA, FOLLIKULIARNAIA FAZA, ПРЕОВУЛЯТОРНАЯ ФАЗА, ФОЛЛИКУЛЯРНАЯ ФАЗА
Italian Fase follicolare del ciclo mestruale, Fase proliferativa del ciclo mestruale, Fase proliferativa mestruale, Fase preovulatoria, Fase follicolare
Croatian FOLIKULARNA FAZA
Polish Faza folikularna, Faza wzrostowa cyklu płciowego
Japanese 卵胞期, 月経-卵胞期, 卵胞期月経, 卵胞期月経周期, 排卵前期, 月経周期-卵胞期
German Follikelphase, Follikelsprungphase, Menstruationszyklus, Menstruation, proliferative Phase, Menstruationszyklus, Follikelsprungphase, Menstruationszyklus, proliferative Phase, Präovulatorische Phase
Dutch Follikelfase, Menstruatiecyclus, follikelfase, Pre-ovulatoire fase, Menstruatiecyclus, proliferatiefase, Menstruele proliferatiefase
Portuguese Fase Folicular do Ciclo Menstrual, Fase Folicular, Fase Pré-Ovulatória, Fase Proliferativa do Ciclo Menstrual, Fase Proliferativa Menstrual
Spanish Fase Folicular del Ciclo Menstrual, Fase Folicular, Fase Preovulatoria, Fase Proliferativa del Ciclo Menstrual, Fase Proliferativa Menstrual
Derived from the NIH UMLS (Unified Medical Language System)

Ontology: Luteal Phase (C0024153)

Definition (MSH) The period in the MENSTRUAL CYCLE that follows OVULATION, characterized by the development of CORPUS LUTEUM, increase in PROGESTERONE production by the OVARY and secretion by the glandular epithelium of the ENDOMETRIUM. The luteal phase begins with ovulation and ends with the onset of MENSTRUATION.
Concepts Organ or Tissue Function (T042)
MSH D008183
English Menstrual Cycle, Luteal Phase, Menstrual Secretory Phase, Phase, Luteal, Phase, Postovulatory, Postovulatory Phase, Secretory Phase, Menstrual, luteal phase, Menstrual Cycle, Secretory Phase, Luteal phase, Luteal Phase
Swedish Lutealfas
Czech luteální fáze
Finnish Keltarauhasvaihe
French Phase sécrétoire du cycle menstruel, Phase post-ovulatoire, Phase postovulatoire, Phase lutéale du cycle menstruel, Phase lutéale, Phase lutéale menstruelle
Russian LIUTEINOVAIA FAZA, IAICHNIKOVYI TSIKL, LIUTEINOVAIA FAZA, POSTOVULIATORNAIA FAZA, ЛЮТЕИНОВАЯ ФАЗА, ПОСТОВУЛЯТОРНАЯ ФАЗА, ЯИЧНИКОВЫЙ ЦИКЛ, ЛЮТЕИНОВАЯ ФАЗА
Japanese 黄体期, 排卵後期, 黄体期月経, 黄体期月経周期, 月経-黄体期
Polish Faza wydzielnicza cyklu płciowego, Faza lutealna
Spanish Fase Secretora del Ciclo Menstrual, Fase Secretora Menstrual, Fase Postovulatoria, Fase Secretoria del Ciclo Menstrual, Fase Secretoria Menstrual, Fase Luteínica del Ciclo Menstrual, Fase Luteínica
Portuguese Fase Luteínica, Fase Luteínica do Ciclo Menstrual, Fase Lútea do Ciclo Menstrual, Fase Secretora Menstrual, Fase Secretora do Ciclo Menstrual, Fase Luteal do Ciclo Menstrual, Fase Luteal, Fase Pós-Ovulatória, Fase Secretória do Ciclo Menstrual, Fase Secretória Menstrual
German Lutealphase, Menstruation, sekretorische Phase, Menstruationszyklus, Lutealphase, Postovulatorische Phase, Menstruationszyklus, sekretorische Phase
Italian Fase luteinica
Dutch Fase, luteale, Luteale fase, Fase, postovulatoire, Menstruele cyclus, luteale fase, Menstruele cyclus, secretiefase, Menstruele secretiefase, Postovulatoire fase, Secretiefase, menstruele
Derived from the NIH UMLS (Unified Medical Language System)

Ontology: Menstrual cycle (C0025329)

Definition (NCI_NCI-GLOSS) The monthly cycle of hormonal changes from the beginning of one menstrual period to the beginning of the next.
Definition (NCI) The Menstrual Cycle involves regularly recurring hormonal changes and physiologic endometrial changes during the reproductive period in human females, and some primates, and culminates in partial sloughing of the endometrium (menstruation) in the absence of fertilization. For most women, one cycle takes 28 days. (NCI)
Definition (CSP) period from onset of one menstrual bleeding to the next in an ovulating woman or female primate.
Definition (MSH) The period from onset of one menstrual bleeding (MENSTRUATION) to the next in an ovulating woman or female primate. The menstrual cycle is regulated by endocrine interactions of the HYPOTHALAMUS; the PITUITARY GLAND; the ovaries; and the genital tract. The menstrual cycle is divided by OVULATION into two phases. Based on the endocrine status of the OVARY, there is a FOLLICULAR PHASE and a LUTEAL PHASE. Based on the response in the ENDOMETRIUM, the menstrual cycle is divided into a proliferative and a secretory phase.
Concepts Organism Function (T040)
MSH D008597
SnomedCT 78456001
English Cycle, Menstrual, Cycles, Menstrual, Menstrual Cycle, Menstrual Cycles, sex cycle (human female), estrous cycle, menstrual cycle, normal menstrual cycle, normal menstruation cycle, menstrual cycles, Normal menstrual cycle (finding), Normal menstrual cycle, menstrual; cycle, period; menstrual, Normal menstrual cycle, NOS, Menstrual cycle
Swedish Menstruationscykel
Czech menstruační cyklus
Finnish Kuukautiskierto
Russian IAICHNIKOVYI TSIKL, SEKRETORNAIA FAZA, MENSTRUAL'NYI TSIKL, ENDOMETRIAL'NYI TSIKL, PROLIFERATIVNAIA FAZA, МЕНСТРУАЛЬНЫЙ ЦИКЛ, ПРОЛИФЕРАТИВНАЯ ФАЗА, СЕКРЕТОРНАЯ ФАЗА, ЭНДОМЕТРИАЛЬНЫЙ ЦИКЛ, ЯИЧНИКОВЫЙ ЦИКЛ
Croatian MENSTRUACIJSKI CIKLUS
Polish Cykl endometrialny, Cykl jajnikowy, Faza proliferacyjna, Faza sekrecyjna, Cykl miesiączkowy
Norwegian Not Translated[Menstrual Cycle]
Dutch cyclus; menstrueel, menstrueel; cyclus, Cyclus, menstruatie-, Menstruatiecyclus
Spanish ciclo menstrual normal (hallazgo), ciclo menstrual normal, Ciclo Menstrual
French Cycle menstruel
German Menstruationszyklus
Italian Ciclo mestruale
Portuguese Ciclo Menstrual
Derived from the NIH UMLS (Unified Medical Language System)

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