Mid-Luteal Progesterone

Definition - What does Mid-Luteal Progesterone mean?

Mid-luteal progesterone is a test that is done to confirm the release of an egg and is performed by obtaining a blood sample during the middle of the luteal phase of the menstrual cycle to measure the levels of progesterone in blood. If the ovaries fail to release the egg after maturation, which is also known as anovulation, the corpus luteum is not formed and there would not be an increase in progesterone levels in blood during the luteal phase.

Anovulation can impair the ability of a woman to conceive, therefore confirmation of ovulation is an important step in the evaluation of a couple for infertility.

FertilitySmarts explains Mid-Luteal Progesterone

Progesterone is the predominant hormone during the luteal phase. The luteal phase of the menstrual cycle begins after the release of the egg from the developing follicle and typically extends from day 14 to around day 28 in a 28-day menstrual cycle. The cells of the follicle transform into the corpus luteum that starts producing high levels of progesterone to prepare the uterus for implantation by increasing the glands and blood vessels in the inner lining of the uterus.

If a woman is having regular 28-day menstrual cycles, blood is taken for measurement of mid-luteal progesterone on day 21 of the cycle. If the periods are irregular, the test is done 7 days prior to the expected date of menstrual bleeding and thereafter repeated weekly until menstruation occurs.

Interpretation of the mid-luteal progesterone level is as follows:

>30 nmol/L

Normal range. Confirms ovulation.

10-30 nmol/L

Inconclusive. Requires repeating the test and reviewing the timing of the test.

<10 nmol/L

Indicates anovulation.

Ultrasound scanning is another test that can be helpful in confirmation of ovulation. Although less accurate, basal body temperature (BBT) charts, cervical mucus testing, and ovulation predictor kits (OPKS) can also be used to detect ovulation, and they carry the benefit of being able to use at home.

If ovulation is confirmed, the next step is the identification of the underlying cause of anovulation. If it is due to external factors like poor nutrition, lack of physical activity or emotional stress, anovulation can be corrected by modifying the diet and lifestyle. If there is an underlying hormone imbalance, medical treatment is necessary to normalize hormone levels.

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