Molecular Fragments: Birth Control

Site and models created by Dr. Dave Woodcock, Associate Professor Emeritus, UBC (Kelowna).

(email)
Copyright 1996, 1997, 2008 Dave Woodcock
Note on Jmol: For x86 machines, on the molecular model...
Click LH mouse button to rotate
Use the mouse scroll wheel (or Shift + click LH mouse button) to zoom
click RH mouse button for menu
For spacefill model on the menu:
  • choose 'Style'
  • then choose 'Scheme'
  • then 'CPK 'CPK Spacefill'
Choose other model presentations in the same way.

I. Progesterone

Progesterone is the naturally occuring 'birth control' chemical. In the second half of the menstrual cycle it prepares the uterus, and prevents release of more eggs if pregnancy occurs.

Progesterone, injected into the body, can mimic a pregnancy and so stop ovulation. However, injection is not a practically solution to birth control, and taken orally it was ineffective.

II. Norethindrone

Norethindrone is one of a number of chemicals that have the same effect in the body as progesterone and which are effective when taken orally.

Structurally, note that norethindrone lacks one of the methyl groups of progesterone, and the substituent COCH3 has been replaced by an OH group and an acetylene group.

Birth control pills consist of mixtures of an estrogen (to control the menstrual cycle0 and a progestin (such as norethindrone) in varying amounts.

III. Mifepristone (RU 486)

Initiates a spontaneous abortion, and prevents a fertilized egg from implantation in the uterus wall thereby preventing pregnancy after fertilization has taken place. Since it is taken after the impregnation it is sometimes refered to as the 'Morning after' pill.

Controversy reigns in the US due to the chemical being used to initiate abortions after attachment to the uterus wall has occured, thereby replacing a surgical procedure.

page upkeep by Dave: (email) who is solely responsible for the contents.

This document page last modified (mo/day/year) :