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Understanding
Your Cycle (simplified)
The monthly fertility pattern which occurs regularly in most women
beginning at puberty and ending at menopause is called the menstrual
cycle. Each cycle is divided into two parts --- before ovulation
and after ovulation. Over a 28-day period the cycle typically follows
this pattern:
Part 1. Day 1 of your cycle is the day menstruation (or bleeding) begins and usually lasts
from 3-5 days. This first part, from menstruation to ovulation,
may vary from 13 to 20 days in length and is referred to as the
follicular phase of the cycle, as this is when the follicle
develops the mature egg. The actual length may not only differ
from one woman to another but also differs in some women from month
to month. It is during this critical first part of the cycle that
fertilization can occur. The regularity of this pattern may
be upset by such common occurrences as sickness, stress, physical
exertion or even climate changes. A rise in the level of Luteinizing
Hormone (LH) accompanies a change in the cervical mucous in anticipation
of the follicle rupturing and releasing a mature egg towards the
end of this first half of the cycle. (The change in cervical mucous allows sperm in the vagina access the uterus and fallopian tubes.)This surge in hormone level
can be detected in your urine and is commonly used to predict ovulation
and your fertile period. The ruptured follicle becomes the corpus
luteum and produces hormones that effect the rest of the cycle.
Part 2. The second part of the cycle, from ovulation to
menstruation, is about the same length in all women, and is called
the luteal phase. It is during this part that the egg travels
down the fallopian tube toward the uterus --- an event which
consistently occurs 14 to 16 days before the onset of menstruation
regardless of the length of a woman's menstrual cycle. If a
single male sperm unites with the egg while it is in the tube the
fertilized egg may attach to the spongy lining of the uterus. Pregnancy
begins if this "implantation" takes place. If fertilization does
not take place the egg or will break apart in a day or two. At about
Day 25, hormone levels begin to drop. This causes the lining of
the uterus to break down and in a few days it is shed in a menstrual
period. Another cycle has begun.
For access to some excellent mini movies produced through PBS covering
human reproduction, and the role of sperm and egg, go to the following
link PBS
MOVIES
Pregnancy can be detected by the rise in HCG levels, which will
quickly rise after successful implantation of an embryo. Some home
tests can detect this rise as soon as within 10-12 days past ovulation.
Go to our Fertility
Store
to view or order LH and HCG test kits.
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