Progesterone is a hormone in the body that stimulates and regulates various functions. It's produced in the ovaries, the placenta (when you get pregnant) and the adrenal glands. It helps prepare your body for pregnancy and conception, regulates your menstrual cycle and impacts your libido. If you don't have enough progesterone, you may have difficulty getting or staying pregnant.
Progesterone levels fluctuate throughout your menstrual cycle. Your numbers rise each month during the second half of the menstrual cycle, about seven days before your period. That's because one of this hormone's most important functions is to cause the uterine lining to secrete special proteins to prepare it for an implanted fertilized egg. If the lining isn't thick enough, implantation won't happen.
If you don't have an implantation, your estrogen and progesterone levels drop. Your uterine lining breaks down, and you get your period.
If you do have an implantation and get pregnant, progesterone is produced in the placenta and the levels remain high during pregnancy. Levels are even higher if you're having multiples.
The combination of high estrogen and progesterone levels suppresses ovulation during pregnancy. Progesterone also promotes the growth of milk-producing glands in the breast during pregnancy.
"Normal" progesterone levels depend on a person's age and gender. In women, factors also include where she is in her menstrual cycle and whether she's pregnant.
Low progesterone causes
Low progesterone levels may be caused by:
- Possible miscarriage
- Ovulation or ovary problems
Low progesterone symptoms
If you aren't pregnant, some symptoms of low progesterone include:
- Low libido
- Hot flashes
- Migraines or headaches
- Depression, anxiety or other mood changes
- Menstrual cycle irregularity or absence
If you're pregnant, you need progesterone to maintain your uterus until you give birth. If your levels are too low, you may be unable to carry the baby to term.
Some symptoms of low progesterone levels in pregnant women include:
- Abdominal pain
- Frequent low blood sugar
- Regularly tender breasts
- Constant fatigue
- Vaginal dryness
Progesterone and estrogen hormones complement one another. So, when you don't have enough progesterone, estrogen dominates. And that can lead to symptoms such as:
- Depression, mood swings or low libido
- Weight gain
- Heavy bleeding
- Irregular menstrual cycle
- Premenstrual syndrome
- Breast tenderness
A simple blood test—a PGSN, or progesterone test—can help your health care provide assess if your progesterone levels are too low. It can help you figure out why you're having trouble getting pregnant, confirm if you've ovulated, monitor hormone replacement therapy (see below) and assess the status of a high-risk pregnancy.
Low progesterone treatment
Several types of treatments can help address low progesterone symptoms. If you're trying to conceive, hormone therapy can help increase progesterone and thicken your uterine lining. That may improve your chances of conception. If you have severe menopause symptoms, your hormone therapy will likely be a combination of progesterone and estrogen.
Natural remedies to boost low progesterone levels include:
- Eating more foods with zinc such as shellfish
- Upping your intake of vitamins B and C, which help maintain progesterone levels
- Regulating stress levels (cortisol is released when you're very stressed, reducing progesterone levels)
For more information, check out our piece on progesterone.