The Menstrual Cycle
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Day 1 starts with the first day of your period. This
occurs after hormone levels drop at the end of the
previous cycle, signaling blood and tissues lining the
uterus (womb) to break down and shed from the
body. Bleeding lasts about 5 days. |
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Usually by Day 7, bleeding has stopped. Leading up
to this time, hormones cause fluid-filled pockets
called follicles to develop on the ovaries. Each follicle
contains an egg. |
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Between Day 7 and 14, one follicle will continue to
develop and reach maturity. The lining of the uterus
starts to thicken, waiting for a fertilized egg to
implant there. The lining is rich in blood and
nutrients. |
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Around Day 14 (in a 28-day cycle), hormones cause
the mature follicle to burst and release an egg from
the ovary, a process called ovulation. |
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Over the next few days, the egg travels down the
fallopian tube towards the uterus. If a sperm unites
with the egg here, the fertilized egg will continue
down the fallopian tube and attach to the lining of
the uterus. |
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If the egg is not fertilized, hormone levels will drop
around Day 25. This signals the next menstrual cycle
to begin. The egg will break apart and be shed with
the next period. |
Content last updated March 5, 2009.
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