What Is Luteal Phase Defect (LPD)?

Luteal Phase Defect (LPD) is a treatable condition which may go undetected without adequate diagnosis and can lead to both difficulty conceiving and early miscarriage. In an attempt to simplify this complex but common condition, it helps to have in place some basic knowledge of the cycles which affects a woman’s reproductive capacity: the menstrual cycle and the ovarian cycle.

The Menstrual Cycle

Proliferative Phase

Growth of endometrium under influence of estradiol. *Corresponds with Follicular Phase.

Secretory Phase

Endometrium stops growing and starts producing secretions (used to nourish an implanted embryo). *Corresponds with Luteal Phase.

Menstrual Phase

Endometrium sheds (the “period”) due to withdrawal of progesterone. (Corresponds with end of Luteal Phase & beginning of Follicular Phase.)

The menstrual cycle refers to the cyclical development and then shedding of the endometrium, the lining of the uterus. This cycle has three phases, as written above.

The Ovarian Cycle

Follicular Phase

Prior to ovulation, indicated by growth of follicles and a dominant follicle, and production of estradiol. Approximately 14 days in length, this phase typically becomes shorter as women age. “FP” corresponds with the Proliferative Phase of the menstrual cycle.

Luteal Phase

After ovulation, indicated by the corpus luteum (left from the ruptured follicle after ovulation) and production of progesterone. Approximately 11 to 16 days in length. Menstruation signals end of Luteal Phase / begin of Follicular Phase. “LP” corresponds with the Secretory Phase of the menstrual cycle.

The ovarian cycle refers to the cyclical development and then expelling of the egg from the ovary. This cycle has 2 phases, as illustrated, which optimally correspond with the phases of the menstrual cycle.

If a woman’s luteal phase is shorter than average, it may be considered a Luteal Phase Defect, or LPD. The luteal phase may be shortened as a result of a prior defect of the follicular phase or a defect of the development of the tertiary follicle. The result can be either (a) a defect in an ovulated egg, or (b) a luteinized unruptured follicle. (A luteinized unruptured follicle is caused if during her LH (luteinizing hormone) surge, a woman produces only enough LH to cause the follicle to produce progesterone, but not enough to cause the follicle to rupture and release it’s egg.)

Luteal Phase Defect


Ovulatory dysfunction affecting the second half of the menstrual cycle, also referred to as inadequate or insufficient luteal phase

Caused by

Hormonal imbalance(s)

Results in

Development of uterine lining that is out of phase with the fertilized egg and resulting inappropriate implantation



Testing hormone levels through blood draws & specially-timed endometrial biopsy


Hormone therapies such as progesterone supplements, hCG, GnRH, clomiphene citrate

More simply stated, LPD is a hormonal imbalance, affecting ovulatory function and uterine endometrial lining, which can increase a woman’s risk of both conception difficulties and early miscarriage. The “gold standard” of diagnostic techniques for LPD is the endometrial biopsy, which is performed to see if the two cycles are “in sync.” One young mom, Angela, gives the example of her experience with an endobiop: “When I was diagnosed with LPD, my uterine lining was dated at day 22, but my period started the next day…”

The balancing of a woman’s reproductive hormones is a delicate matter easily affected by a variety of factors. LPD is detectable and treatable, but only if the medical provider knows what to look for in the diagnostic phase. A patient who has her basal body temperature chart handy may be able to provide important clues to her physician regarding her own luteal phase. Staying keenly aware of her body’s other monthly changes will enhance her diagnosis.