What Is Luteal Phase?

Written on November 25, 2023 by Sendra Yang, PharmD, MBA. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

Table of contents

• The Menstrual Cycle
• More About The Luteal Phase
• Premenstrual Syndrome Symptoms
• Hormone Testing With Everlywell
• Related Content

Numerous women struggle with having a regular menstrual period.[1] A menstrual period is vaginal bleeding that usually occurs monthly as part of the menstrual cycle. Menstrual irregularities are reported to occur in approximately 14% to 25% of women of childbearing age.[2] Additionally, many women also experience premenstrual symptoms before their period.[1] It is estimated that more than 90% of women state they get premenstrual symptoms, such as bloating, headaches, and moodiness.

The menstrual cycle is inclusive of a luteal phase, and premenstrual symptoms typically appear during this phase. If you don’t recognize that term you may wonder what is the luteal phase. Let us dive more into the menstrual cycle, focusing on the luteal phase, with information on premenstrual syndrome symptoms.

The Menstrual Cycle

Various hormones in the body help to regulate different bioprocesses. The menstrual cycle is no different; it is the hormonal process a woman’s body goes through every month to prepare for a possible pregnancy.[1,3] During the monthly menstrual cycle, the body makes different levels of hormones, and the fluctuations can lead to various menstrual symptoms. These hormone levels also change as a woman gets older. The menstrual cycle is regulated by luteinizing and follicle-stimulating hormones, estrogen, and progesterone.[3]

A menstrual cycle typically lasts 28 days but can vary slightly, with most cycles between 25 to 30 days.[1,3,4] A menstrual cycle starts on the first day of a period, also called menstruation, and the cycle begins again when the next period occurs. Menstruation is the bleeding that occurs when the lining of the uterus is shed.[3] Typical menstrual bleeding lasts from four to eight days.[3] Irregular or heavy, painful periods are not considered normal.[1,3]

The menstrual cycle has three phases.

Follicular

The follicular phase averages around 13 or 14 days and is the phase preceding the release of an egg.[1,3] During the follicular phase, estrogen and progesterone levels are low, leading to the breakdown and shedding of the thickened uterus lining. This shedding results in menstrual bleeding. Around this time, the follicle-stimulating hormone increases slightly to stimulate several follicles in the ovaries to develop. Follicles are fluid-filled sacs that each contain an egg. As the follicular phase progresses, the follicle-stimulating hormone levels decrease, allowing only one follicle to continue developing. As this follicle develops, it produces estrogen, thereby raising estrogen levels.

Ovulatory

The ovulatory phase is when the egg is released from the follicles in the ovaries.[1,3] This phase starts with sudden elevated levels of luteinizing and follicle-stimulating hormones. The luteinizing hormone stimulates the release of the egg, which occurs about 16 to 32 hours after the start of the surge in levels. During this time, estrogen levels decrease, and progesterone levels begin to rise.

Luteal

The luteal phase occurs after the egg is released and lasts 12 to 14 days.[1,3-5] During this phase, the luteinizing and follicle-stimulating hormones decrease, the ruptured follicle closes after releasing the egg, and the corpus luteum forms. The corpus luteum is a normal cyst containing a group of cells that is formed at the site of the follicle in the ovaries, and it starts producing progesterone and estrogen.[5,6] The estrogen and progesterone levels are high in the luteal phase, causing the uterus lining to thicken. The thickening of the uterine lining prepares the environment for a possible pregnancy where a fertilized egg can implant or attach.

More About The Luteal Phase

The luteal phase begins after ovulation when an egg starts the journey from the follicles in the ovaries to the uterus.[5] The luteal phase ends just before a menstrual period.[3,5] In the luteal phase, the basal body temperature slightly increases until the menstrual period starts again. If the released egg is not fertilized or if a fertilized egg is not implanted, the corpus luteum disintegrates after 14 days, the levels of estrogen and progesterone decrease, and a new menstrual cycle initiates.

During the luteal phase, conception can occur, and the uterus lining thickens with fluids and nutrients to help nourish a potential embryo. If an embryo can be implanted, the cells around the developing embryo produce a hormone called human chorionic gonadotropin to maintain the corpus luteum. The increase in human chorionic gonadotropic levels is what is detected in pregnancy tests. The mucus in the cervix also thickens to prevent sperm or bacteria from entering the uterus. The increased estrogen and progesterone levels in this phase can also cause breast milk ducts to dilate, which may lead to breast swelling and tenderness.

Premenstrual Syndrome Symptoms

Premenstrual syndrome (PMS) is a combination of symptoms that occur a week or two before menstruation.[1] PMS happens after ovulation and before the menstrual period, meaning that it occurs during the luteal phase. Some of the signs and symptoms of the luteal phase are similar to those of premenstrual syndrome symptoms. Symptoms may include mood changes, tender breasts, bloating, breaking out or acne, and appetite changes.[5] Other symptoms are constipation or diarrhea, cramping, or lower tolerance to light and noise.[1] Additional symptoms related to emotional or mental health include fatigue, irritability, mood changes, sleep issues, and depression.

Hormone Testing With Everlywell

Everlywell has an option for an at-home Women’s Fertility Test (you collect the sample at home and send it to a laboratory for sample testing). Several hormones play a role in the ovulation process and menstrual cycle. This lab test checks five key hormone levels that can affect your menstrual cycle, ovulation, and ability to become pregnant. The five hormones are estradiol, thyroid-stimulating hormone, total testosterone, follicle-stimulating hormone, and luteinizing hormone.

Related Content

What Is Follicular Phase?

Pregnancy Bloating vs. Period Bloating: What's the Difference?

Does Diabetes Affect Fertility?

References

1. Menstrual cycle. Menstrual Cycle, Office on Women’s Health. https://www.womenshealth.gov/menstrual-cycle. Accessed November 16, 2023.
2. How many women are affected by menstrual irregularities? Eunice Kennedy Shriver National Institute of Child Health and Human Development. https://www.nichd.nih.gov/health/topics/menstruation/conditioninfo/affected. Accessed November 16, 2023.
3. McLaughlin JE. Menstrual cycle - women’s health issues. Merck Manuals Consumer Version. https://www.merckmanuals.com/home/women-s-health-issues/biology-of-the-female-reproductive-system/menstrual-cycle. November 12, 2023. Accessed November 16, 2023.
4. Reed BG, Carr BR. The Normal Menstrual Cycle and the Control of Ovulation.[Updated 2018 Aug 5]. In: Feingold KR, Anawalt B, Blackman MR, et al., editors. Endotext [Internet]. South Dartmouth (MA): MDText.com, Inc.; 2000-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK279054/.
5. Luteal phase of the menstrual cycle: Symptoms & length. Cleveland Clinic. https://my.clevelandclinic.org/health/articles/24417-luteal-phase. Accessed November 16, 2023.
6. Corpus luteum: Development, anatomy & function. Cleveland Clinic. https://my.clevelandclinic.org/health/body/21849-corpus-luteum. Accessed November 16, 2023.