Progesterone, referred to as the “pregnancy hormone” is produced by the ovaries after ovulation. Progesterone prepares the lining of the uterus for the fertilized ovum and helps maintain pregnancy. This steroidal hormone converts the lining of the womb into a soft spongy bed to accommodate implantation of a fertilized egg. If implantation does not occur, progesterone levels fall and menstruation begins. In the event of pregnancy however, progesterone will be produced by the attached placenta. Small amounts of progesterone are produced in the adrenal glands as well.
In addition to menstruation and pregnancy, progesterone also affects contractions of the fallopian tubes, thickens the consistency of vaginal mucus, and raises body temperature slightly.
Progesterone levels in the body fluctuate depending on menstrual cycles.
During the first half of the menstrual cycle, the concentration of progesterone in the bloodstream is less than 1 ng/ml. During the second half, or luteal phase, progesterone in the bloodstream ranges from 3 ng/ml to 25 ng/ml. If pregnancy occurs, the placenta takes over the output of progesterone, producing very high levels of the hormone, up to 30 times greater than normal peak levels. Following birth, the progesterone level drops abruptly.
How does progesterone therapy work?
Progesterone belongs to a class of medications known as “progestins”. These are essentially, female hormones.
Women may take progesterone for a number of medical reasons:
- To help treat menopausal symptoms
- To induce a menstrual period
- To treat abnormal uterine bleeding
- To help control severe PMS symptoms
- To supplement estrogen as part of hormone replacement therapy
- To reduce withdrawal symptoms when certain drugs, including (benzodiazepines) are no longer used
- To aid in ART (assisted reproductive technology)/Fertility
*If estrogen is taken without progesterone, the risk of uterine cancer is increased.
If a woman has had a hysterectomy, she may be prescribed estrogen by itself. If she has not, she may be given estrogen plus progestin.
How is progesterone administered?
Biosynthesized progesterone is produced in a laboratory and combined with other substances to create pills, creams, lotions, gels, vaginal suppositories, and injectable solutions.
These are prescribed for a number of conditions including:
- Hot flashes
- Reduced libido
- Memory loss
- Uterine fibroids
- Fibrocystic breasts
- Abnormal uterine thickening
- Weight gain
- Cervical expansion
- Menopause (this also includes the surgical removal of ovaries, or ovaries damaged by disease or treatment for cancer)
Who needs progesterone therapy?
Women who suffer with infertility, PMS, and severe menopausal symptoms may benefit greatly from progesterone therapy. Synthetic progesterone is created to mimic natural progesterone released from the female ovaries or produced by the placenta during pregnancy.
Testing Progesterone Levels
In order to test for progesterone deficiencies, a progesterone blood test or serum progesterone may be ordered by a physician or other healthcare practitioner. Individuals may also order progesterone tests online, for in-home collection. These tests will measure the level of progesterone in the blood.
Side Effects of Progesterone
A 15-year research study, known as the Women’s Health Initiative (WHI) was conducted to assess the health of postmenopausal women.
Included, were findings relating to hormone replacement therapies, their safety, and connection to terminal illness. At this time, it does not appear that progesterone alone promotes breast cancer in women.
Common side effects may include the following, however:
- Breast tenderness
- Muscle/joint pain
- Mood swings
- Runny nose
- Vaginal discharge
- Urination problems
Serious, but uncommon side effects include:
- Breast lumps
- Migraine headache
- Speech difficulties
- Numbness in arm or leg
- Lack of coordination
- Shortness of breath
- Rapid heartbeat
- Chest pain
- Coughing up blood
- Swelling in face and extremities
- Disturbances in vision
- Vaginal bleeding
- Shaking hands
- Stomach pain
- Itching/skin rash
- Difficulty breathing or swallowing
Trade names for progesterone include:
- Medroxyprogesterone acetate (MPA)
- Amen, Cycrin, Provera
- Prochieve 4% Norgestrel
- Micronor, Nor-QD
- Norethindrone acetate
Progesterone, while an important and effective therapeutic intervention should be taken only when necessary, for the shortest amount of time possible. Because of their potency, and potential for side effects, a medical professional should closely monitor all hormone replacement therapies.
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6NHLBI women’s health initiative (WHI) (no date) Available at: https://www.nhlbi.nih.gov/whi/ (Accessed: 25 January 2017).
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