What is the corpus luteum?

During your reproductive years, your body will regularly prepare for pregnancy, whether you’re planning to become pregnant or not. The result of this preparation cycle is a woman’s menstrual cycle.

The menstrual cycle has two phases, the follicular phase and the postovulatory, or luteal, phase. The luteal phase lasts for approximately two weeks. During this time, a corpus luteum forms in the ovary.

The corpus luteum is made from a follicle that housed a maturing egg. This structure starts to form as soon as a mature egg pops out of the follicle. The corpus luteum is essential for conception to occur and for pregnancy to last.


The primary purpose of the corpus luteum is to pulse out hormones, including progesterone.

Progesterone is required for a viable pregnancy to occur and to continue. Progesterone helps the uterine lining, known as the endometrium, to thicken and become spongy. These changes in the uterus allow for implantation of a fertilized egg.

The uterus also provides a rapidly growing embryo with nourishment during its earliest stages of development until the placenta, which also produces progesterone, can take over.

If a fertilized egg doesn’t implant in the endometrium, a pregnancy doesn’t occur. The corpus luteum shrinks away, and progesterone levels drop. The uterine lining is then shed as part of menstruation.

Corpus luteum defect

It’s possible to have a corpus luteum defect, also referred to as luteal phase defect. It’s caused if there’s not enough progesterone in the uterus to thicken the endometrium. It can also occur if the endometrium doesn’t thicken in response to progesterone, even if some progesterone is present.

A corpus luteum defect can be caused by many conditions, including:

Corpus luteum defect can also occur for unknown reasons. When this happens, you might be given a diagnosis of unexplained infertility.

Many of the conditions that lead to corpus luteum defects also cause infertility or miscarriage.

Symptoms of corpus luteum defect

Symptoms of corpus luteum defect can include:

  • early pregnancy loss or recurrent miscarriage
  • frequent or short periods
  • spotting
  • infertility


There isn’t a standard test used to diagnose a corpus luteum defect. Your doctor will likely recommend hormonal blood tests to measure your progesterone level. They may also recommend vaginal sonograms to view the thickness of your uterine lining during the luteal phase.

Another possible diagnostic test is an endometrial biopsy. This biopsy is taken two days before you expect to get your period. If your periods are irregular, your doctor will schedule the test sometime after the 21st day of your cycle.

For this test, your doctor removes a tiny piece of your endometrial lining to analyze under a microscope.


If you aren’t ovulating regularly or at all, your doctor can try to stimulate ovulation with medications, such as clomiphene (Clomid, Serophene), or injectable gonadotropins, such as human chorionic gonadotropin (hCG). These medications may be used alone or in conjunction with procedures, such as intrauterine insemination or in vitro fertilization (IVF). Some of these medications will increase your chance of twins or triplets.

You doctor may prescribe a progesterone supplement for you to take after ovulation takes place. Progesterone supplements are available as oral medications, vaginal gels, or injectable solutions. You and your doctor can discuss the pros and cons of each to determine which is best for you.

If you’re having early or recurrent miscarriages due to a corpus luteum defect, your doctor will most likely prescribe progesterone without the need for additional, ovulation-boosting medication.


A corpus luteum defect is highly treatable. If you have an underlying condition, such as endometriosis or polycystic ovarian syndrome, additional treatments or lifestyle modifications will also be needed. You can discuss these with your doctor.

Tips for conception

There are things you can do to help preserve or maintain fertility, which may help you to conceive easier:

  • Keep your body mass index in the normal range. Being overweight or underweight can have a negative impact upon hormonal health.
  • Know your family history. Some diagnoses of infertility seem to run in families. These include polycystic ovarian syndrome (on either the father’s or mother’s side), primary ovarian insufficiency (formerly known as premature ovarian failure), and endometriosis. Celiac disease may also affect fertility.
  • Maintain a healthy lifestyle, which includes not smoking cigarettes, eating a balanced diet, reducing carbohydrate intake, and exercising regularly.
  • Reduce your stress level with meditation, yoga, or deep breathing exercises.
  • Consider acupuncture. Studies have found a positive correlation between conception and acupuncture. There are also improved conception rates among women who’ve received acupuncture to decrease stress and increase blood flow to the uterus.
  • Avoid toxins, known as endocrine disruptors, in the environment. These include coal byproducts, mercury, phthalates, and bisphenol A (BPA).
  • Track your ovulation with a reputable at-home testing device. Don’t use ovulation apps or a basal body temperature thermometer.

Talk to your doctor if you’ve been trying unsuccessfully to conceive for over a year if you’re under age 35, or over six months if you’re age 35 or older. Your doctor can help you come up with a plan to improve your chances for conception.