Progesterone Blood Testing and the Menstrual Cycle

General Guidelines

Progesterone is a steroid hormone produced by both males and females and is necessary for sexual health and reproduction. Although it is often referred to as a “female hormone” because of its predominant role in ovulation and pregnancy, men require it too, albeit in smaller amounts.

In women, progesterone is produced mainly in the ovaries and the placenta (if pregnant). Small amounts are also produced in the adrenal glands. Low progesterone in women can cause symptoms like irregular periods and trouble conceiving. In men, progesterone is produced in the adrenal glands and in the testes.

Progesterone blood testing, also referred to as “progesterone, serum” testing, measures the level of progesterone in a sample of blood to help monitor hormone levels for pregnancy or to diagnose a medical condition or concern. This test is crucial for assessing the role of progesterone in preparing the uterus for pregnancy, supporting pregnancy, and diagnosing infertility or adrenal gland disorder.

Progesterone levels can drop due to various factors, leading to low progesterone, which may cause irregular periods and other symptoms. Certain medications such as oral contraceptives, progesterone, ampicillin, and clomiphene may affect test results.

Radioactive tracers used in thyroid and bone scan tests within seven days of blood draw may also skew results. Some progesterone testing must be done on specific days within a woman’s menstrual cycle to accurately test progesterone levels.

Why is the Progesterone Test Used

Progesterone Test in Women

A progesterone blood test may be used to detect or monitor a number of medical conditions, including:

• Fertility issues
• Progesterone treatment during pregnancy
• High-risk pregnancy (high progesterone levels)
• Ovarian cysts
• Molar pregnancies
• Ovarian cancer
• Adrenal cancer
• Congenital adrenal hyperplasia (CAH) (low progesterone levels)
• Toxemia (in later stages of pregnancy)
• Decrease in ovarian function
• Absence of menstruation (amenorrhea)
• Ectopic pregnancy
• Miscarriage
• Abnormal uterine bleeding (non-pregnant women)

The corpus luteum, which forms in an ovary after the ovary releases an egg, plays a crucial role in progesterone production to support pregnancy. If pregnancy does not occur, the corpus luteum breaks down, leading to a drop in progesterone levels, causing noticeable symptoms and preparing the lining of your uterus for the next menstrual period by causing it to shed if fertilization does not happen.

Progesterone Test in Men

The progesterone blood test may be used to detect low levels of the hormone in males who may experience:

• Decreased libido
• Loss of hair
• Weight gain
• Fatigue
• Depression
• Gynecomastia (male breasts)
• Erectile dysfunction

Low levels of progesterone are associated with a higher risk of arthritis, osteoporosis, prostatism (difficulties with urination as a result of obstruction), and prostate cancer.

How does the Progesterone Test work?

A progesterone test, or progesterone, serum test measures progesterone levels in the blood. In men, progesterone is a necessary precursor to testosterone and a “preserver of masculinity.” Produced mainly in the testes, progesterone levels decline with age, along with testosterone.

In addition to progesterone testing, men may have estrogen, cortisol, DHEA, and thyroid hormone tests performed as well. In reproduction, progesterone signals the female uterus to prepare for the implantation of a fertilized egg. As the fetus grows, the placenta also provides high levels of the hormone to support the pregnancy.

During pregnancy, progesterone prevents the production of milk. The sharp decline in labor then triggers the body to start producing. Progesterone levels rise and fall with a woman’s menstrual cycle so timing is very important for monitoring some medical conditions or situations.

Progesterone levels fluctuate throughout the menstrual cycle, with a significant drop if fertilization does not occur, leading to menstrual bleeding. An FSH (follicle-stimulating hormone), LH (luteinizing hormone), hCG (human chorionic gonadotropin), estrogen, or thyroid test may be performed along with the progesterone serum test for women.

About Progesterone Test Results

Results for progesterone testing are reported in nanograms per milliliter (ng/mL) and may vary by laboratory. Interpreting progesterone test results is crucial for understanding a woman's menstrual cycle, pregnancy status, and potential fertility issues.

Progesterone levels fluctuate based on the menstrual cycle phase, pregnancy, or menopause, providing insights into ovulation, the health of the pregnancy, and the risk of miscarriage or ectopic pregnancy. When progesterone levels drop, it can trigger menstrual bleeding if fertilization does not occur.

Normal ranges are as follows:

• Women before ovulation, postmenopausal women, and men: less than 1 ng/mL
• Women mid-cycle: 5 to 20 ng/mL
• Pregnant Women:
  • 1st trimester: 11.2 to 90 ng/mL
  • 2nd trimester: 25.6 to 89.4 ng/mL
  • 3rd trimester: 48.4 to 42.5 ng/mL

Ranges above or below normal could indicate one of the medical conditions listed above.

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