What Every Woman Should Know About Her Luteal Phase

luteal phase
The luteal phase is the second half of your menstrual cycle, which takes place after ovulation and ends when you get your next period. The average luteal phase typically lasts from 12-16 days, and is usually about the same length of time each month. It can be also as short as 10 days. During the luteal phase, your body prepares for the possibility of a pregnancy.

After you ovulate, the corpus luteum — a structure inside the ovaries that holds a developing egg—collapses and begins to produce progesterone. Progesterone helps the endometrium thicken and become more vascular so that if there is a fertilized egg, it has a “soft pillow” on the uterine lining in which to implant itself. If no egg implants, the corpus luteum stops producing progesterone and you shed your uterine lining in your period.

Short video explanation of luteal phase

The Body in the Luteal Phase

Progesterone has the side effect of raising the woman’s basal body temperature. The shift in basal body temperature between the follicular and the luteal phase is to 0.5°C (0.9°F).

Likely, the amount of mucus will decrease (some women experience dryness or no feeling in the vagina), or the color-texture of the cervical mucus will change to a lower quality.

When progesterone is high, women may experience tender breasts and nipples. Confoundingly, this is also an early pregnancy symptom. If you are charting your cycles and you know where you are throughout, you can dismiss this early tenderness as a possible effect of post-ovulation progesterone. However, if the tenderness continues or intensifies when you normally do not experience this sensitivity, you may be experiencing early signs of pregnancy.

The high content of progesterone can also precipitate premenstrual syndrome symptoms such as mood swings, anxiety, and irritability.

Why Is the Length of the Luteal Phase So Important?

IMPORTANT: When you’re trying to get pregnant, the length of the luteal phase is one of the most important keys to pay attention to.

It provides a wealth of information about your hormonal balance, your cycle regularity, progesterone secretion, and your ability to conceive.

If your luteal phase is under 10 days, it’s a sign that your body isn’t making enough progesterone (i.e. luteal phase deficiency). A fertilized egg may not have sufficient time to implant and burrow into the uterine lining before the progesterone starts to decrease, signaling the body to shed the lining and become your next period.

If the luteal phase is sufficiently long, the egg has plenty of time to implant and to signal the ovaries to start producing Human chorionic gonadotropin (hCG), the hormone detected in pregnancy tests.

Your progesterone levels matter even if you aren’t trying to conceive. Adequate progesterone is crucial for maintaining healthy bones, long-term heart health, sleeping well, and feeling your best.

Luteal Phase Deficiency

Luteal phase deficiency (LPD) has been diagnosed in 3-20% of patients who are infertile, and in 5-60% of patients experiencing recurrent pregnancy loss. However, data shows that 6-10% of women who are fertile demonstrate an inadequate luteal phase, which confirms the need for a better understanding of normal variations in the menstrual cycle, as well as in variations that could be pathologic.

What Causes a Short Luteal Phase?

Some of the causes for shorten luteal phase are:

  • polycystic ovarian syndrome (a disorder that causes enlarged ovaries with small cysts),
  • endometriosis (a condition where tissue normally found inside the uterus starts to grow outside the uterus),
  • thyroid disorders (such as an overactive or an underactive thyroid, Hashimoto’s disease, and iodine deficiency),
  • anorexia (and milder forms of restrictive eating),
  • obesity,
  • excessive exercise,
  • aging,
  • stress (When we are chronically stressed, our adrenal glands produce too much cortisol. You might not think there is a connection between cortisol and progesterone but they are linked. Cortisol’s production comes first, before all other hormone production and it blocks progesterone receptors.)

How Do You Test Your Progesterone Level?

IMPORTANT: Test progesterone when it’s highest, which is about halfway through your luteal phase. It’s when you are 5-7 days after ovulation, and 5-7 days before your period.

The best plan is to try to detect ovulation and then count 5-7 days after. There are two ways to do it:

  • Test with LH ovulation test strips. Start testing your urine a few days before you think you’ll ovulate. When you see the double line indicating LH surge, count 5-7 days later, and then have the blood test (If you suffer PCOS, you may have chronically elevated LH, and so cannot rely on ovulation test strips.).
  • Chart your cycle. Using analogous/digital thermometer to take your basal body temperature every morning as a way to confirm ovulation, and also as a great way to assess progesterone without a blood test.

How Can You Lengthen Your Luteal Phase?

Treatment for a short luteal phase will vary depending on what’s causing it.

IMPORTANT: The most common cause for luteal phase defect is a hormonal imbalance.

There are many causes of hormone imbalance, such as lack of nutrition, toxins in the body from improper eating habits (processed food, fast food) and from the environment. Fortunately, lengthening the luteal phase due to low progesterone levels is the easiest of fertility problems to treat and correct.

The changes in the extension of the luteal phase may be noticed in a period of 3-6 cycles by taking the following supplements:

  • Vitamin C: A study in Fertility and Sterility showed that Vitamin C increases fertility in some women with short luteal phases. In the study, 25% of the women who received Vitamin C had gotten pregnant within six months compared to the placebo group in which only 11% got pregnant.
  • Vitamin B: Green leafy vegetables (spinach, turnip greens, swiss chard, mustard greens, etc.) are rich in B vitamins which are necessary for proper hormonal balance. Vitamin B6 (so called luteal phase vitamin) has been found to be most effective for lengthening a short luteal phase. Some of the best sources of vitamin B6 are poultry, seafood, bananas, liver, potatoes and fortified cereals, as well as alfalfa, spirulina, bee pollen, watercress, irish moss, kelp and blue green algae. You may also take synthesized vitamin B6 in conjunction with a synthesized B vitamin complex to avoid causing imbalances: this is a personal choice, really. Suggested usage is 50mg up to 100mg daily.
  • Agnus Castusis a great hormone balancer and menstrual cycle regulator. Studies show that Agnus Castus helps normalize progesterone levels and increase the luteal phase of your ovulation cycle so that implantation can take place. It is a herbal food supplement made of the berries of the plant. Agnus Castus is safe to take during pregnancy (until the 10th week for the continued support of the corpus luteum – to help prevent miscarriages) and can be taken all month long while trying to conceive. However, the beneficial effects of Agnus Castus can take awhile to show results, so don’t expect immediate changes. It has been shown to take 3 months or more, as the herb builds up it’s effects in your body.
  • Red Raspberry leaf tea balances hormones and nourishes and tones the uterus and the entire endocrine system.
  • Progesterone cream: use it only during your luteal phase. (Adding progesterone during your follicular phase could prevent ovulation.) Continue to use the progesterone cream after confirming pregnancy to prevent miscarriage due to a sudden drop in progesterone levels. Then wean off slowly after the 10th week of pregnancy.


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  4. Robert W. Reber, Gregory F. Erickson. Reproductive endocrinology and infertility. Goldman’s Cecil Medicine. 2012. 24th edition.
  5. Natalie M. Crawford, David A. Pritchard, Amy H. Herring, Anne Z. Steiner. Prospective evaluation of luteal phase length and natural fertility. Fertility and Sterility. 2017 Mar. 107(3):749-755.
  6. Siklósi GS, Bánhidy FG, Ács N. Fundamental role of folliculo-luteal function in recurrent miscarriage. Arch Gynecol Obstet. 2012 Nov. 286(5):1299-305.
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  8. Xia Wang, Tommaso Falcone, Marjan Attaran, Jeffrey M. Goldberg, Rakesh K Sharma. Vitamin C and vitamin E supplementation reduce oxidative stress-induced embryo toxicity and improve the blastocyst development rate. Fertility and Sterility. 2002 Dec. 78(6):1272-1277.
  9. Hina Zahid, Ghazala H. Rizwani, Sumaira Ishaqe. Phytopharmacological review on vitex agnus-castus: A potencial medicinal plant. Chinese Herbal Medicines. 2016 Jan. 8(1):24-29.

We hope you found this post helpful.

About the Author

My name is dr. Simona Medvescek and I help and support women and couples on their fertility journey.

I am a professional fertility awareness educator for more then 10 years. I have made a training in accordance to the standards of the AG NFP working group from Koeln, Germany.

To this day I consulted with over 500 women and couples.

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