What do oral contraceptives do?

The way the birth control works is fairly straight forward. Okay, so I'm sure controlling the hormones involved isn't so simple, but the affect on a woman's body is fairly easy to understand. From what I can tell, it plays out the same way whether you're on a combination pill (estrogen and progestin), or the minipill (progestin only).

(Sorry, I haven't really talked about the difference between the combination pill and the minipill. Having to research my posts takes way more time than just throwing my thoughts all slap-dash together in a few paragraphs.)

Basically, when a woman takes an oral contraceptive, it causes the mucus in her cervix to thicken, while thinning the lining of the uterus, preventing an egg to implant there. Taking an oral contraceptive can also prevent ovulation all together. Simple, right? Hm.

Here's a website from the Association of Reproductive Health Professionals that has a nice animated graphic on how menstruation works and how it's affected by different birth control methods: http://www.arhp.org/hormonalcontraception/

Here's a link to the Mayo Clinic's resources on oral contraceptives: http://www.mayoclinic.com/health/birth-control/MY01182/DSECTION=birth-control-pills

Here's a link to a fact sheet by the American Collage of Obstetricians and Gynecologists on the pill:
http://www.acog.org/~/media/For%20Patients/faq021.pdf?dmc=1&ts=20130416T2308279410

Here's a link from the Women's Health Resource Center, which is run by a non-profit organization called Healthy Women: http://www.healthywomen.org/condition/birth-control-pills

Finally, once again I give you the Wikipedia page on how oral contraceptives work (do you see a theme emerging?):
http://en.wikipedia.org/wiki/Combined_oral_contraceptive_pill#Mechanism_of_action

Ciao,

Andrea