Where do babies come from, anyway?

The ovaries are one amazing set of organs, I have learned in the few weeks following my Dx. Both reproductive and endocrine - you might call them the command center for the hormonal workings of the female body. Before you can understand anything about premature ovarian failure, you need to understand exactly how the female reproductive and endocrine systems work.

Short version
Uterus builds up endometrium (lining) in anticipation of release of egg. Ovary releases egg. If sperm is in wait, egg should fertilize. The fertilized egg travels down the fallopian tube to the uterus and implants in the endometrium. Cue: pregnancy. If there is no sperm to fertilize the egg, then the egg and endometrium are flushed out in that lovely process known as menstruation. And then the whole process starts over again.

For the visual learners

Image credit: Fertility Plus (http://www.fertilityplus.org/faq/hormonelevels.html)

A Hormonal Primer
Let's take a look at exactly what's happening hormonally during a woman's cycle. If you've ever wondered why some women might get a little "moody" during their cycle, well, we've got a LOT going on at once hormonally in our bodies :)

Follicular (Pre-Ovulatory) Phase
The pituitary gland begins releasing FSH (Follicle Stimulating Hormone). This primes the ovary to start maturing its follicles, the individual part of the ovary that releases the eggs. During this phase, several follicles actually develop at once, on both ovaries, but only one follicle will mature and release an egg in most normal circumstances. Estradiol (estrogen) is released by the ovaries during this time, and aids in the building of the endometrial lining of the uterus.

Ovulatory Phase
As estrogen levels peak, it triggers the release of LH (Lutenizing Hormone) by the pituitary gland. Of all the developing follicles, one will mature and burst, releasing the egg. It is currently unknown how the body determines which of these follicles on which ovary will release an egg. The ruptured follicle then becomes the corpus luteum (Latin for "yellow body"), and begins to release progesterone. Progesterone is a heat-releasing hormone, and causes a woman's BBT (Basal Body Temperature) to rise. It's also responsible for hot flashes. Progesterone is essential to ensuring implantation of the fertilized egg and to sustain pregnancy. If the egg is fertilized, it will take about 7-10 days to implant in the uterus. Once implanted, the fertilized egg will begin to release the hormone hGC (Human Chorionic Gonadotropin). This is the hormone that POAS HPTs (pee-on-a-stick home pregnancy tests) are designed to detect. The corpus luteum will continue to release progesterone, until the placenta develops and takes over progesterone production for the duration of the pregnancy.

Luteal Phase
If the egg is not fertilized, the corpus luteum will begin to disintergrate, and thus, decrease the amount of progesterone released. The drop in progesterone causes a second rise in estrogen, which then triggers the uterus to shed the endometrium, inducing a woman's menses. And then it starts all over again.

What does this all mean for me?
Well, my remaining ovary isn't working anymore for some presently unknown reason, so NONE of this is happening in my body right now.