Progesterone is a hormone responsible for fertility and menstruation.
Females secrete progesterone from the corpus luteum, a structure of cells within the ovaries.
Progesterone prepares the endometrium, the innermost lining of the uterus, for pregnancy. The hormone helps thicken the endometrium to support implantation.
If pregnancy occurs, the body and the placenta will continue to release progesterone to support the growing fetus. Levels of the hormone continue to rise throughout pregnancy.
Though doctors understand the importance of progesterone in females, they know little about the hormone’s role in males.
In this article, we explore the symptoms of low progesterone levels and the treatment options.
Without this hormone, the body cannot prepare the right environment for the egg and developing fetus. If a woman becomes pregnant but has low progesterone levels, there may be an increased risk of pregnancy loss.
Signs of low progesterone levels include:
- abnormal uterine bleeding
- irregular or missed periods
- spotting and abdominal pain during pregnancy
- recurrent pregnancy loss
Since estrogen and progesterone work together to regulate fertility and the menstrual cycle, low progesterone levels may cause estrogen levels to rise.
Someone with high estrogen may experience:
- decreased libido
- weight gain
- gallbladder issues
Conditions related to low progesterone levels include:
A menstrual cycle of 32 days or longer may also indicate a lack of ovulation. A doctor can measure progesterone levels to diagnose anovulation.
Females with a regular menstrual cycle might not ovulate, and doctors should check for low progesterone levels.
Endocrine Society guidelines recommend screening all females for ovulation dysfunction.
In some cases, women may require hormone supplementation to support their pregnancy.
Researchers suggest that preterm birth may occur when progesterone levels are low.
Progesterone might help maintain the uterus in the later stages of pregnancy by blocking factors that cause preterm delivery.
Those taking estrogen for menopause who have not had a hysterectomy must also take progesterone supplements to help prevent uterine cancer.
A blood test can confirm someone’s progesterone levels.
Throughout different stages of the menstrual cycle, progesterone levels will fluctuate.
During the first half of the menstrual cycle, called the follicular phase, progesterone levels will be less than 1.5 nanograms per milliliter (ng/ml).
Just before ovulation, this hormone increases. It then rises again within a week after ovulation.
Throughout pregnancy, doctors measure progesterone levels to track how the corpus luteum and placenta are working.
During the first trimester, maternal progesterone increases slowly to around 40 ng/ml.
Between the sixth and eighth weeks of pregnancy, doctors consider low progesterone levels to be less than 10 ng/ml, which is a sign of an abnormal or ectopic pregnancy.
In the remaining trimesters of pregnancy, progesterone levels continue to increase to 150 ng/ml.
After menopause, progesterone levels fall below 0.5 ng/ml.
Although a blood test can detect low progesterone levels, other factors are important. Doctors may need to carry out further tests to diagnose the cause.
Females with low levels of progesterone may require supplementation. Depending on the cause, doctors will prescribe different forms of the hormone. They will also choose a progesterone treatment based on the likelihood of any side effects.
For example, some people cannot tolerate side effects from oral progesterone and may receive the hormone as a topical cream or gel.
To prevent preterm birth, doctors may recommend intramuscular injections of progesterone or progesterone suppositories.
People taking hormone replacement therapy for menopause symptoms may also require progesterone supplementation.
In some cases, fertility specialists may prescribe progesterone suppositories.
Anyone who notices symptoms of low progesterone, such as irregular periods, may wish to speak to a doctor if they are concerned or trying to conceive.
A doctor may refer them to a gynecologist, who specializes in women’s health, or a hormone specialist known as an endocrinologist.
If a person is younger than 35, experts recommend that they consult a healthcare professional after 12 months of trying to conceive naturally. Those who are older than 35 may wish to speak to a doctor earlier.
Females with low progesterone levels may have irregular periods and difficulty conceiving.
Blood tests can detect low levels of the hormone, after which further tests can help determine the underlying cause.
To correct low progesterone levels, doctors may prescribe different forms of the hormone. The right treatment depends on the cause and takes into account the potential side effects for the person.
Anyone who suspects that they have low progesterone levels should consult a doctor.