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Body Literacy: Progesterone

Your cycle is irregular? “Check your progesterone.”

You have severe PMS? “You probably need progesterone supplementation.”

You have serious postpartum depression? “Get a shot of progesterone.”

You had a miscarriage? “Your doctor should have had you on progesterone.”

What is the magic bullet that seems to be the answer for all of our reproductive woes?


Meet this necessary hormone that is produced by the corpus luteum (the sac left after the egg is released in ovulation). The second half of the menstrual cycle is ruled by progesterone.

Progesterone prepares the uterine lining for a fertilized egg, and if conception does not occur, progesterone will fall signaling the shedding of the lining and start of a new cycle. When pregnancy is achieved, progesterone establishes the placenta, encourages growth of breast tissues, and strengthens the pelvic wall muscles.

Progesterone is crucial for healthy cycles and healthy pregnancies. If you need a refresher on progesterone's role within the menstrual cycle, check out the first post in this Body Literacy series: Menstrual Cycle 101.

Symptoms that may point to low progesterone are:

Recurrent miscarriage

Luteal phase (post-peak phase) less than 10 days

Days of brown spotting before next period

Mid-cycle bleeding

Severe PMS


Irregular cycles

Anovulatory cycles

If you suspect progesterone may be low, there are a few options to consider— and NONE of them involve hormonal birth control for cycle correction 🙌🏻.

**Note: Short luteal phase is an expected finding in the first 3-4 cycles postpartum.**

Progesterone strips (for at-home use) such as Proov. You can start testing 3 days post ovulation.

(I tell my clients to wait until 4-5 DPO if they are concerned about using too many tests).

You can do the test at home and have results within 5 minutes. It does not give a quantitative result, just a positive or negative. The test will read positive when progesterone is greater than 5µg/ml (which is high enough to confirm ovulation).

Blood draw: Day 7 post peak

Marquette is great because it identifies an objective, accurate peak!

Some providers order a “day 21 progesterone” but this is based on a day 14 peak and 28 day cycle. It is more accurate to have it drawn 7 days post peak using a definitive peak reading.

**Note: Progesterone is secreted in pulses. If a woman were to have 10 progesterone levels drawn in a single day, the levels may actually vary considerably.**

"Serum progesterone levels can fluctuate 8-fold in a 90-minute period during the midluteal phase and range from 2.3 to 40.1 pg/mL during a 24-hour period in the same healthy subject. Because this rapid fluctuation traverses almost the entire range of luteal values, there can be no standard for appropriate luteal phase progesterone in fertile women and, therefore, a single value can neither diagnose nor exclude LPD in patients."

Progesterone levels

According to the American Pregnancy Association, ”Progesterone levels also can have quite a variance. They can range from 9-47ng/ml in the first trimester, with an average of 12-20ng/ml in the first 5-6 weeks of pregnancy.”

Follicular phase <1 ng/mL

1-28 ng/ml Mid Luteal Phase (Peak +7 )

9-47 ng/ml First trimester

17-146 ng/ml Second Trimester

49-300 ng/ml Third Trimester

Other providers routinely supplement progesterone in the first trimester

>/= 40ng/ml: no supplementation needed

>25 ng/ml: Intramuscular injection supplementation

20-25 ng/ml: Intramuscular injection supplementation (higher dose)

Under 20 ng/ml: Intramuscular injection supplementation and vaginal suppositories

According to the APA, cited above, 12-20 is the average in the first 5-6 weeks of pregnancy, which would require nearly every pregnant woman to be supplemented in the practices using certain guidelines.

Progesterone Supplementation

If your progesterone level is low, your provider has the option to prescribe a supplement in the form of oral, injection, or vaginal suppository. Vaginal suppository is often shown to be the route with the greatest absorption by endometrial tissue (tissue in the uterus).

For women trying to regulate cycles, progesterone is typically taken for 10 days during the post peak phase can help relieve symptoms. Pregnant women may need supplementation for various amounts of time depending on their doctor’s protocol.

There is disagreement throughout the medical community about standards for progesterone supplementation. One extreme is doctors who feel progesterone rarely needs to be supplemented, and others who believe every woman needs it. When considering the pulsation of progesterone and the potential inaccuracy of a one-time blood draw (because it could be 8 times higher if you wait an hour and draw it again) these differences in practice are likely to remain for the foreseeable future.

We must be careful not to fall in to a trap of thinking women’s bodies are broken by design and in need of “fixing” to sustain a pregnancy. It is also important to advocate for appropriate supplementation when the need arises!

Progesterone supplementation isn’t an intervention that should be done routinely on every woman. Injection sites have risk for infection as the skin is broken and a needle introduced in to the body. I recently heard a provider speaking of a pregnant woman who spent 8 weeks with a wound-vac due to an infection of the progesterone injection site.

Additionally, some doctors who follow protocols resulting in widespread supplementation do not use progesterone supplements that are covered by insurance. This is financially cumbersome for an routine intervention when covered alternatives are available. You can always ask your provider to seek a treatment option covered by insurance— I’ve done this a few times recently with our pediatrician. At times, there are no alternatives, but that is the exception, not the rule.

Knowledge is power. Understand YOUR body and YOUR options so you can advocate for YOUR needs.

More thoughts to consider when progesterone is supplemented:

If in pregnancy, for how long?

If daily (not pregnant), will ovulation be suppressed?

When progesterone is given through an entire pregnancy, it can prevent natural onset of labor. Progesterone level naturally falls toward the end of pregnancy to signal the body to go in to labor, just as the fall in progesterone in a cycle signals the body to shed the uterine lining for the start of a new period.

A common complaint of women whose doctors use a protocol requiring progesterone very late into pregnancy is that they no longer go into labor on their own. Women who previously had spontaneous labor are now requiring inductions.

If progesterone is taken daily, which can be prescribed postpartum for women struggling with postpartum depression or anxiety, a conversation needs to be had with the provider about the dose. Daily progesterone will likely prevent ovulation, but if a couple is trying to avoid pregnancy, they need to be educated on the risks and likelihood of a breakthrough ovulation.

Progesterone Supplementation Research

There is much more research to be had. Two recent compelling studies seem to show opposite conclusions at first glance— until you dig a little deeper.

Progesterone IS shown to have an effect on pregnancy outcomes when started in the luteal phase before pregnancy is confirmed. When waited and started after pregnancy is confirmed, it may not have an effect on the pregnancy outcome. Knowing your cycles and addressing any deficiencies BEFORE a positive pregnancy test could be the key to maximizing the effects of supplementation, if it’s needed.

Progesterone is important.

Progesterone supplementation is an important tool. Progesterone is vital to female fertility and pregnancy. There are absolutely diseases and conditions which clinically result in low progesterone in need of supplementation. Progesterone can be a way to manage irregular cycles and support high risk pregnancies, especially those with history of preterm labor. Clinical symptoms, such as these, are likely a better indication of progesterone deficiency when compared to lab values that rapidly fluctuate. (Much to my dismay! I strongly prefer an objective lab value— except for when it is potentially quite inaccurate.)

You should be ovulating. Ovulation is a sign of health. Progesterone is one way to confirm ovulation, and if cycles are irregular, progesterone supplementation can be a way to help balance things out while lifestyle changes are implemented for long term management. With recurrent miscarriage and within infertility treatments, progesterone is regularly used with success and evidence to back its use.

In other cases, there are pros and cons to weigh when deciding if supplemental progesterone is the way to go. Knowing your cycle, your symptoms, and why your doctor does or does not supplement progesterone--is all very important in being able to advocate for *your* body and *your* healthcare needs.

Additional Resources/Research

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