Re: What happens when the ovum is not fertilized?

Hey Miriam!

Before I launch into the answer to your question, I think a brief overview
of the female reproductive system may be wise.  First, you have the ovaries.
These organs store all of the immature egg cells and produce mature egg
cells, or ovum.  Next in line are the fallopian tubes, which are 
responsible for the transport of the mature ovum to the uterus.  The uterus
is a balloon-like sac that has lots of stretchy muscles which holds a
developing fetus when the female is pregnant.  The uterus opens into the
vagina, or the birth canal, through which the baby exits the mother’s body.

Once a month (about every 28 days), the ovary produces a mature ovum.  It 
is released into the fallopian tubes where it takes 3 to 4 days to reach 
the uterus.  During that time, the uterus thickens its lining in 
preparation for the incoming ovum.  If the ovum is fertilized, it will 
implant itself in this lining.  However, if fertilization does not occur 
(hey, I’m FINALLY going to answer your question!!) the ovum withers away 
and the uterus gets rid of the extra lining through the birth canal.  This 
process is referred to as menstruation.  So as long as the mature ovum 
produced every month is not fertilized, this release of uterus lining 
occurs once every 28 days.

I hope that answers your question!

Brian
:)