Menstrual cycle
APARNA.C.LAKSHMY
CLINICAL INSTRUCTOR
SNEHODAYA COLLEGE OF NURSING

Definition
 The cyclic events that take place in a
rhythmic fashion during the reproductive
period of a woman’s life is called menstrual
cycle.
 MC starts at the age of 12-15 years.
 First occurrence of menstruation called
menarche
 Permanent cessation of MC is called
menopause(45-50 years)
 Duration of menstrual cycle- 28 days.

 Changes during menstrual cycle:
 Ovarian changes
 Uterine changes
 Vaginal changes
 Changes in cervix

Ovarian changes:
 Two phases
 Follicular phase
 Luteal phase

Follicular phase:
 Extends from the 5th day of the cycle until
the time of ovulation, which takes place on
14th day.
 There is Maturation of ovum with development
of ovarian follicles through different stages.

Ovarian follicles
 OF are the glandular structures occupying the
stroma of cortex.
 Each follicle consists of the ovum surrounded
by epithelial cells namely granulosa cells.
 The follicles gradually grow into a matured
follicle through various stages

Various stages
 Primordial follicle
 Primary
 Vesicular
 Matured or graafian follicle

Primordial follicle
 PF has an ovum which is incompletely
surrounded by the granulosa cells
 These cells provide nutrition to the ovum
throughout the childhood
 Secretes oocyte maturation inhibiting factor .

Primary follicle.
 Primordial follicle becomes primary follicle
when the ovum is completely surrounded by
the granulosa cells.
 Changes includes,
 Proliferation of granulosa cells and increase in
size of the follicle.
 Increase in size of ovum.
 Onset of formation of connective tissue
capsule around the follicle

Vesicular follicle
 Under the influence of FSH ,about 6-12
primary follicles start growing and develops to
vesicular follicles .
 Changes are,
 Changes in granulosa cells
 Changes in ovum
 Formation of capsule.

 Changes in granulosa cells.
 Proliferation of granulosa cells occurs.
 Some irregular spaces appear in between the granulosa cells.
 These spaces fuse to form a cavity called follicular cavity or
antrum.
 Antrum is filled with a serous fluid called the liquor folliculi.
 Increase in size of antrum and follicle.
 Ovum is pushed to one side and surrounded by granulosa
cells which forms the germ hill,.
 Granulosa cells which line the antrum form membrane
granulosa.
 Cells of germ hill become columnar and form corona
radiata

Changes in ovum
 Ovum increases in size.
 Nucleus become larger and vesicular
 Cytoplasm become granular
 Thick membrane called zona pellucida formed
around the ovum.
 A narrow cleft appears between ovum and
zona pellucida.cleft is called perivitelline
space.

Formation of capsule
 A covering sheath is formed around the follicle
known as follicular sheath or theca folliculi.
 The theca folliculi divides into 2 layers
 Theca interna-inner vascular layer.it contains
epithelial cells which secretes female sex
hormones especially estrogen.
 Theca externa –outer layer of follicular
capsule

Graafian follicle
 GF is the matured ovarian follicle with maturing ovum.
 Changes are,
 Increase in size
 Zona pellucida ,theca interna becomes thick
 At one point, the follicle protrudes upon the surface of
the ovary called stigma.
 More epithelial cells start secreting female sex
hormones.
 On the 14th day of MC ,GF is ready for the process of
ovulation.

ovulation
 Ovulation is the process by which the
graafian follicle in the ovary ruptures and, the
ovum is released into the abdominal cavity.
 Occurs on the 14th day of menstrual cycle in
a normal cycle of 28 days.

Process of ovulation
 Rupture of graafian follicles takes place at the stigma
 Follicular fluid oozes out.
 Germ hillock is freed from wall.
 Ovum is expelled out into the abdominal cavity along
with some amount of fluid and granulosa cells.
 From abdominal cavity, the ovum enters the fallopian
tube through the fimbriated end.

 After fertilization ,the ovum is called zygote.
 From fallopian tube ,the zygote reaches the
uterus on 3rd day after ovulation
 If fertilization doesnot occur, the ovum
degenerates

Determination of ovulation time
 Daily recording of basal body temperature. There
will be a rise of 0.5 C above normal after
ovulation.
 Endometrial biopsy specimen shows secretory
changes if ovulation has occurred
 Cervical mucus will be thick and cellular after
ovulation. Fern pattern will be absent after
ovulation.
 Estimation of blood FSH and LH shows high values
at the time of ovulation.
 lower abdominal pain in the midcycle indicates
ovulation.

Luteal phase
 Phase extends between 15th and 28th day of menstrual cycle.
 During this phase corpus luteum is developed and hence this
phase is called luteal phase.
 After the ovum is released, the follicle is filled with blood
which is called as corpus hemorrhagicum..
 Granulosa cells proliferate and cavity gets filled with lipid
rich luteal cells which is called as corpus luteum / or yellow
body.
 Functions-Corpus luteum secretes estrogen,progesterone,inhibin
and relaxin.it also help for maintaining pregnancy by the
hormones secreted by corpus luteum until placenta starts
secreting estrogen and progesterone

 Fate of corpus luteum:
 If the ovum is not fertilized,corpus luteum starts
degenerating and forms corpus luteum menstrualis.
 Afterwards, by about the 28th day, it forms a whitish scar
called corpus albicans.now there is no secretion of
estrogen and progesterone and next cycle begins.
 If fertilization occurs, the corpus luteum is maintained
by HCG ,which is essential for the maintenance of
pregnancy .after 3-4 months ,placenta starts secreting
hormones and corpus luteum degenerates

Uterine changes
 3 phases
 Menstrual phase
 Proliferative phase
 Secretory phase.

Menstrual phase
 After ovulation ,if fertilization doesnot occur,the ovum becomes
zygote and it gets implanted on the uterine wall leading to
pregnancy.
 If pregnancy doesnot occur,the thickened endometrium is shed or
desquamated.
 This desquamated endometrium is expelled out through vagina along
with some blood and tissue fluid.
 The process of shedding and exit of uterine lining along with
blood and fluid is called menstruation or menstrual bleeding.
 This period is called menstrual phase or menstrual period.
 The day when bleeding starts is considered as the first day of the
menstrual cycle.
 Menstruation occurs when there is sudden reduction in the release
of estrogen and progesterone .

 Menstruation stops between 3rd and 7th day
of menstrual cycle.
 At the end of menstrual phase,the thickness
of endometrium is only about 1mm.

Proliferative phase.
 PP extends usually from 5-14th day of menstruation .
 It corresponds to the follicular phase of ovarian cycle.
 The endometrial cells proliferates, so that the
endometrium reaches the thickness of 3-4 mm at the
end of proliferative phase.
 Uterine changes during proliferative phase occur
because of the influence of estrogen released from
ovary.
 On 14th day ,ovulation occurs under the influence of LH
followed by secretory phase.

Secretory phase
 Extends between 15th and 28th day of the menstrual
cycle.
 After ovulation ,corpus luteum is developed in the ovary.
 It secretes a large quantity of progesterone along with a
small amount of estrogen.
 Estrogen is responsible for repair of damaged
endometrium and growth of glands.

 Progesterone is responsible for the further
growth of endometrial glands and secretory
activites in the endometrium.
 If fertilization occurs,further changes occurs in
the uterus for the survival of the developing
fetus.if the ovum unfertilized,menstruation
occurs after this phase and a new cycle begins

 Changes in cervix
 Proliferative phase;
Under the influence of estrogen,the mucus
membrane of cervix becomes thinner and alkaline.
 Secretory phase;
Because of progesterone action,the mucus
membrane of cervix becomes more thick and
adhesive.

Vaginal changes
 Proliferative phase;
 The epithelial cells of vagina are cornified
because of the action of estrogen.
 Secretory phase;
 Vaginal epithelium proliferates due to the
action of progesterone.

Hormonal regulation of menstrual cycle.
 Hormones involved in regulation
 Hypothalamic hormone-GnRH
 Anterior pituitary hormones- FSH and LH
 Ovarian hormones- estrogen and progesterone

LH
PROGESTERONE

Hypothalamus-GnRH
Anterior pituitary- FSH AND LH
FSH stimulates LH stimulates
Growing follicles ovaries ovulation corpus luteum
Initial secretion of
estrogen by growing
follicles
Further development of ovarian
follicles and secretion of
estrogen,progesterone,and inhibin
Secretion of
progesterone,estrogen,relaxin,
inhibin
estrogens progesterone relaxin inhibin

 Estrogen
 Promotes development and maintenance of female
reproductive structures,feminine secondary sex
characters
 Moderate levels inhibit release of GnRH,FSH,LH

 Progesterone
 Works with estrogens to prepare endometrium
for implantation,
 Prepare mammary glands to secrete milk
 Inhibits release of GnRH and LH

RELAXIN
 Inhibits contractions of uterine smooth muscles.
 During labor increases flexibility of pubic
symphysis and dilates uterine cervix
Inhibin
 Inhibits release of FSH and to a lesser extent LH

 FSH- the concentration of FSH in the blood shows a
peak before the day of ovulation
 LH –concentration of LH shows a sharp increase just
before the day of ovulation.this is known as LH
surge.
 Estrogen - concentration shows 2 peaks
1.Before the day of ovulation
2.Middle of luteal phase.
 Progesterone- peak around the middle of luteal
phase.

Applied physiology
 Menstrual symptoms
Unpleasant symptoms with discomfort which appear in many
women during menstruation.
It includes,
Abdominal pain
Dysmenorrhea (menstrual pain)
Headache
Occasional nausea and vomiting
Irritability
Depression
Migraine

Premenstrual syndrome (PMS)
 It is the symptom of stress that appears
before the onset of menstruation.
 It is also called premenstrual stress
syndrome,premenstrual stress or premenstrual
tension.
 It lasts for about 4-5 days prior to
menstruation.

Common features are,
 Mood swinging
 Anxiety
 Irritability
 Emotional instability.
 Headache
 Depression
 Constipation
 Abdominal cramping
 Bloating(abdominal swelling)

Abnormal menstruation
 Amenorrhea- absence of menstruation during
reproductive period of females.
 Hypomenorrhea-decreased menstrual bleeding.
 Menorrhagia- excess menstrual bleeding
 Oligomenorrhea-decreased frequency of
menstrual bleeding.
 Polymenorrhea- increased frequency of
menstruation.

 Dysmenorrhea-menstruation with pain.
 Metrorrhagia- uterine bleeding in between
menstruations

Anovulatory cycle.
 It is the menstrual cycle in which ovulation doesnot
occur.
 Menstrual bleeding occurs but the release of ovum
doesnot occur.
 Causes
 Hormonal imbalance
 Prolonged exercise
 Eating disorders
 Hypothalamic dysfunctions
 Tumors in pituitary gland,ovary or adrenal gland.
 Long term use of drugs like steroidal oral contraceptives.

Menopause
 Defined as the period characterized by
permanent cessation of menstruation.
Climacteric
 It is the period in old age when reproductive
system undergoes changes due to the
decreased secretion of sex hormones estrogen
and progesterone.

Postmenopausal syndrome.
 It is the group of symptoms that appear in women
immediately after menopause.
 Mainly caused by lack of estrogen and progesterone.
 Symptoms:
 Hot flashes,fluctuation in blood
pressure,fatigue,nervousness,emotional instability,mental
depression,insomnia,palpitation,vertigo,headache,numbness,uri
nary disturbance,osteoporosis
 treatment
 Hormone replacement therapy.

pregnancy

fertilization
 Refers to fusion of male and female gametes to form a
new offspring.
 Ovum is released from graafian follicle of ovary into the
abdominal cavity at the time of ovulation.
 From abdominal cavity,ovum enters one of the fallopian
tubes through fimbriated end.
 If sexual intercourse occurs at this time,the sperms travel
through the vagina and uterus to reach fallopian tubes
within 60 mins.
 The movement of the sperm through uterus is facilitated
by the antiperistaltic contractions of uterine muscles.

 During fertilization,only one sperm enters the ovum by
penetrating the corona radiata present around the ovum
which is facilitated by proteolytic enzymes present in the
acrosome.
 After fertilization,the ovum divides to a matured ovum
and second polar body.

Sex determination
 22 xx + 1 xx =23 pair of chromosome.(female)
 22 xx + 1 xy = 23 pair of chromosome(male)
 Sex chromosomes are responsible for sex determination.
 During fertilization of ovum,23 chromosomes from ovum and
23 from sperm unite to form 46 chromosome.
 Ovum contains x chromosome and sperm contain either x
chromosome or y chromosome.
 When the ovum is fertilized by a sperm with x
chromosomes,the child will be female with xx chromosome.
 If the ovum fertilized by a sperm with y chromosome,the child will
be male with xy chromosome.

implantation
 Process by which the fertilized ovum implants in the
endometrial lining of uterus.
 After the fertilization,the ovum is known as zygote.
 The zygote takes 3 to 5 days to reach the uterine cavity
from fallopian tube.
 Just before implantation,the zygote develops into morula
and the implantation starts.
 A layer of spherical cells called trophoblast cells is formed
around the morula.
 The trophoblast cells release proteolytic enzymes over the
surface of endometrium.these enzymes digest the cells of
endometrium.now the morula moves through the digested
part of endometrium and implants itself

 when implantation occurs,there is further
increase in the thickness of endometrium.
 At this stage,the endometrial cells are called
decidual cells and the endometrium at the
implanted area is called decidua.

Corpus luteum of pregnancy.
 If pregnancy takes place,the corpus luteum
continues to grow attaining its largest size
until the placenta functions properly.this is
known as corpus luteum of pregnancy.
 It is maintained by the action of hCG secreted
by placenta.
 It degenerates in the later months forming a
fibrous scar.

placenta
 Placenta is a temporary membranous vascular organ that
develops in females during pregnancy.
 It forms a link between the fetus and mother.
 It starts fully functioning only by about 8 weeks after
fertilization.
 The placenta consists of a fetal part and a maternal part.
 It is connected to the fetus by umbilical cord which contains
blood vessels and connective tissues.
 The estrogen and progesterone from corpus luteum
maintains pregnancy upto 8 weeks.the hormone secretion is
facilitated by Human Chorionic Gonadotropin(hCG ) produced
by placenta.
 The average duration of pregnancy in human is 40 weeks or
280 days

Functions of placenta
 Nutritive function
The various nutritive substances,electrolytes and
hormones necessary for the development of fetus
diffuse from the mother’s blood into the fetal
blood through placenta.
 Excretory function
The metabolic end products and waste products from
the fetal body are excreted into the mother’s
blood through placenta.

 Respiratory function
Placenta forms the respiratory organ for fetus.
Oxygen necessary for fetus is received by diffusion from the
maternal blood and carbon dioxide from the fetal blood
diffuses into the mother’s blood through placenta.
 Protective function
Under normal conditions,fetus is not rejected by the mother’s
body even though it is a foreign tissue. Placental membrane
does not allow antibodies and other substances that lead to
rejection
But it allows some protective antibodies like IgG,which provide
passive immunity.

 Endocrine function.
 By 12th week of development,fetus and placenta
function as a unit called fetoplacental unit.
 Fetoplacental unit refers to the interaction between
fetus and placenta in the formation of hormones.
 The placenta produces hormones such as,
 hCG
 Estrogen
 Progesterone
 Human chorionic somatomammotropin( hCS )
 Relaxin.

 hCG stimulates corpus luteum to produce
estrogen and progesterone in the early weeks
of pregnancy.
 Estrogen- for the growth of the uterus and
breasts during pregnancy.
 Progesterone- inhibits uterine contractions and
allow pregnancy to continue.
 hCS promotes breast development and
increases maternal blood glucose level.
 Relaxin relaxes the pelvic ligaments so that
the delivery becomes easier

Tests for pregnancy
 PT depends on the presence of hCG in the urine
or blood of the pregnant woman.
 hCG appears in the urine of pregnant lady about 10
days after fertilization.
 3 methods
 Biological test(oldest method by using experimental
animals)
 Immunological test
 Strip test

Immunological test.
 Principle
To determine the agglutination of latex particles (or sheep RBCs
coated with hCG)
 Procedure
 One drop of hCG antiserum and one drop of urine from
woman who wants to confirm pregnancy is added and mixed
well.if urine contains hCG,all the antibodies of antiserum
are used up for agglutination of hCG molecules.The
agglutination of hCG molecules by antiserum is not visible
because it is colourless.
 Now one drop of latex particles is added to this and
mixed.

 .if urine contains hCG,all the antibodies of antiserum
are used up for agglutination of hCG molecules.No
free antibody is available.
 Later when latex particles are added,these particles
are not agglutinated because,the free antibody is not
available.thus absence of agglutination of latex
particles confirms pregnancy.
 If the urine without hCG is mixed with antiserum,the
antibodies are freely available.when latex particles
are added,the antibodies cause agglutination of these
latex particles.thus it indicates that the woman is not
pregnant

Strip test
 In this method,antibodies to hCG is mixed with
proper dye and incorporated in paper strips.
 This strip is dipped in the urine sample.
 If a purple coloured band develops in the
strip,it indicates pregnancy.
 Radioimmunoassay and enzyme-linked immune
sorbent assay(ELISA) help to quantitatively
measure the level of hCG in samples

parturition
 Refers to expulsion or delivery of the fetus from mother’s body.
 2 process involved in it
 Mechanical and hormonal factors.
 Mechanical factors are due to increasing size of uterus and
stretch of the muscle of uterus.
 Hormonal factors mainly, oxytocin-increases uterine contraction
 Prostaglandins –stimulate uterine contraction
 Progesterone - normally inhibits uterine contraction. But when
its level falls, there is increase in the excitability of the
uterus.

Hormones in the development of
mammary glands.
 Estrogen
 Progesterone
 Prolactin
 Placental hormones
 Other hormones
 Growth hormones,thyroxine,cortisol,relaxin.

Functions of breast.
 The breast produces milk which serves to nourish the
infant.it provides complete nutrition for the newborn
baby and contains carbohydrates,fats and proteins as well
as micronutrients
 Breast secretions also secretions also ensures that
the newborn has a significant amount of immunological
protection.
 To some degree,the breast also has a psychological
function in that it is associated with sexuality.

lactation
 Means synthesis,secretion and ejection of milk.
 It involves 2 processes.
 1.milk secretion
 2. milk ejection

Milk secretion
 Synthesis of milk by alveolar epithelium and
its passage through the duct system is called
milk secretion.
 2phases
 Lactogenesis( initiation of milk secretion)
 Galactopoiesis.(maintenance of milk secretion)

 Lactogenesis( initiation of milk secretion)
Lactogenesis occurs mainly after the delivery of the child. The
milk which is secreted initially is called colostrum.
Role of hormones.
 During pregnancy,mainly in later months,large quantity of
prolactin is secreted.but the activity of this hormone is
suppressed by estrogen and progesterone secreted by
placenta.because of this,lactation is prevented during
pregnancy.immediately after the delivery of baby and
placenta,there is sudden loss of estrogen and
progesterone.now the prolactin is free to exert its action
and promote lactogenesis.

Galactopoiesis.
 Role of hormones
 Prolactin maintains the functional activity of
breast for lactation
 Growth hormones,thyroxine, and cortisol is
essential for continuous supply of
glucose,aminoacids,fatty acids,calcium and
other substances necessary for the milk
production.

Role of hypothalamus in galactopoiesis
 The milk production is continued only if feeding the baby is
continued.
 Suckling of nipple by the baby is responsible for
continuous milk production.
 When the baby suckles,the impulses from touch receptors
around the nipple stimulate hypothalamus.
 Hypothalamus releases some prolactin releasing factors which
cause the prolactin secretion from anterior pituitary.

Milk ejection
 ME is the discharge of milk from mammary
gland
 It depends upon suckling exerted by the baby
and on contractile mechanism in breast,which
expels milk from alveoli into the ducts
 Milk ejection is a reflex phenomenon.it is called
milk ejection reflex or milk let down reflex.
 It is a neuroendocrine reflex.

Milk ejection reflex
 Plenty of touch receptors are present on
the mammary glands.
 When the infant suckles mother’s nipple,the
touch receptors are stimulated and impulses
are discharged.

Effect of lactation on menstrual
cycle.
 Woman who nurses her child regularly doesnot
have menstrual cycle for about 24-30 weeks
after delivery.it is because of prolactin which
inhibits GnRH

Breast milk
 Breast or human milk is the milk secreted by human female.
 Composition- contains 88.5 % water and 11.5% of solids-
lactose,albumin,iron,vitamin A and D and minerals.

Fertility control

Safe period or rhythm method.

Mechanical barriers

Chemical methods
 Available in the form of foam
tablets,jelly,cream or paste.
 it cause destruction of sperms .

Oral contraceptives or pill method
 Prevents pregnancy by inhibiting maturation
of follicles and ovulation
 3 types.
 Combined or classical pills
Taken daily from 5-25th day of menstrual
cycle.

 Sequential pills
Taken from 5- 20th day
Then,23- 28th day
 Minipills or micropills
Taken throughout the menstrual cycle.

Long term contraceptives

intrauterine contraceptive devices

 For prevention of fertilization and
implantation of ovum.

Medical termination of pregnancy
 Dilatation and curettage.

Vacum aspiration

Surgical method
 Tubectomy
 Vasectomy

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