Progesterone is the hormone made by the ovary after ovulation and is responsible for maintaining the lining of the uterus. Progesterone can also be taken during the second half of your menstrual cycle as an infertility medication.

Progesterone is often used when women are suspected to have, or are proven to have, a problem called "luteal phase deficiency". Usually, before progesterone is used, another medicine called clomiphene citrate (Clomid®) is tried. For women taking fertility shots and Lupron® or Synarel®, progesterone is given after ovulation until the pituitary gland is able to recover enough function to send signals to the ovaries which make the body’s own progesterone.

The progesterone is mixed with oil or a wax base into a suppository. This is inserted high into your vagina with your finger. The medication is absorbed by the mucus membrane and the excess drips out.

Start your suppositories when your provider instructs you to do so. This is usually:

• 1 day after insemination

Continue taking the suppositories until one of the following occurs.

• Your period starts.
• Spotting occurs. In this case, come into the lab for a blood pregnancy test. You do not need a paper requisition for a blood pregnancy test at Kaiser. Continue suppositories until you have a negative pregnancy test.
• You do not start your period 14 days after you started the suppositories. Do a blood pregnancy test. If it is positive, continue the suppositories until you are told to stop (usually around 8 weeks of pregnancy). If the pregnancy test is negative, stop the suppositories and your period will start.

Progesterone may extend the length of your cycle making you think that you are pregnant. Some synthetic progesterones have been associated with particular kinds of birth defects. All vaginal suppositories are natural, not synthetic, progesterone and are not thought to be harmful in any way to an early pregnancy.

Progesterone is one of the medications that is used to help the lining of the uterus prepare for implantation.