You probably already know quite a lot about your menstrual
cycle – like how often you get your periods and how heavy they are. In this
page we are going to take a more in-depth look at the female menstrual cycle,
ovulation and periods
INTRODUCTION
The menstrual cycle is the regular natural change that
occurs in the female reproductive system like the uterus and ovaries that make
pregnancy possible. The cycle is required for the production of ovocytes, and
for the preparation of the uterus for pregnancy. Up to 80% of women report
having some symptoms during the one to two weeks prior to menstruation. Common
symptoms include acne, tender breasts, bloating, feeling tired, irritability
and mood changes. These symptoms interfere with normal life and therefore
qualify as premenstrual syndrome in 20 to 30% of women. In 3 to 8%, they are
severe.
MENSTRUAL CYCLE
Women’s cycle lengths vary, and
the most common cycle length is somewhere between 23 and 35 days. Any variation
in menstrual cycle length that does occur is more likely to be during the part
of the cycle before you ovulate (which is called the follicular phase). For
most women, the length of time between ovulation (when an egg is released from
the ovary) and their monthly period is between 12 to 16 days (this is called
the luteal phase).
The first day of your menstrual
cycle is the first day of your period (day 1). The period usually then lasts
anything from 3 to 7 days. You’ll probably find that if you get any period
pains, they’ll be at their worst in the first few days of your period. This is
because the hormones in your body are causing your womb to actively shed the
lining that was built up in the previous menstrual cycle.
At the beginning of your cycle follicle-stimulating hormone (FSH) is
produced by the pituitary gland in your brain. This is the main hormone
involved in stimulating your ovaries to produce mature eggs. Follicles are the
fluid-filled cavities in your ovaries. Each follicle contains one undeveloped
egg. The FSH stimulates a number of follicles to develop and start to produce
the hormone estrogen. Your level of estrogen is at its lowest on the first day
of your period. From then on, it starts to increase as the follicles grow.
Now while a number of follicles initially begin to develop, normally one
follicle becomes “dominant” and this egg matures within the enlarging follicle.
At the same time, the increasing amount of estrogen in your body makes sure
that the lining of your womb is thickening with nutrients and blood. This is so
that if you do get pregnant, the fertilised egg will have all the nutrients and
support it needs to grow. High estrogen levels are also associated with the
appearance of ‘sperm-friendly’ mucus (or, to give it its technical name,
fertile cervical mucus). You may notice this as a thin, slippery discharge that
may be cloudy white. Sperm can swim more easily through this mucus and can
survive in it for several days.
OVULATION
Once the egg (or ovum) has been released, it moves along the Fallopian tube
towards your womb. The egg can live for up to 24 hours. Sperm survival is more
variable, but typically 3-5 days, so the days leading up to ovulation and the
day of ovulation itself are your most fertile – when you are most likely to get
pregnant. As soon as you have ovulated, the follicle starts producing another
hormone: progesterone.
Progesterone causes further build up the lining of your womb in preparation
for a fertilised egg. Meanwhile, the empty follicle within the ovary starts to
shrink, but carries on producing progesterone, and also starts to produce
estrogen. You may get symptoms of pre-menstrual tension (PMS) such as breast
tenderness, bloating, lethargy, depression and irritability at this stage
PERIOD
As the empty follicle shrinks, if the egg is not fertilised, levels of
estrogen and progesterone decrease. Without the high levels of hormones to help
maintain it, the thick womb lining that has been built up starts to break down,
and your body sheds the lining. This is the start of your period and the
beginning of your next menstrual cycle. The first period usually begins between
twelve and fifteen years of age, a point in time known as Menarche. They may
occasionally start as early as eight, and this onset may still be normal
If the egg has been fertilised, it may successfully implant itself into the
womb lining. This usually takes place about a week after fertilisation.
As soon as the fertilised egg has implanted, your body starts producing the
pregnancy hormone, human Chorionic Gonadotrophin (HCG), which will keep the
empty follicle active. It continues to produce the hormones estrogen and
progesterone to prevent the lining of the womb from being shed, until the
placenta (which contains all the nutrients the embryo needs) is mature enough
to maintain the pregnancy
Hope you had a good time in this blog...post your comments and questions for more answers.
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