Luteal Phase Defect (LPD)

Luteal phase defect, or LPD, is a subtle but influential ovulation disorder that can result in conception difficulties.

To understand how LPD stands in the way of conception, you must first understand your body's ovulation cycle:

Two phases of the ovulation cycle:

  • Follicular phase: Part of cycle prior to ovulation, so named due to the fact that this is when the growth and development of the ovarian follicles (which contain oocytes, or eggs) is of primary importance.
  • Luteal phase: Part of the cycle between ovulation and start of new follicular phase, so named because of the importance during this time of luteinizing hormone (LH) and progesterone in preparing the body for pregnancy.

Average length of time

  • Follicular phase - 14 days
  • Luteal phase - 11 to 16 days

When the luteal phase is shorter than normal, implantation of a fertilized egg can be negatively affected, which in turn results in apparent infertility. We say "apparent" infertility because in many of these cases, the egg is indeed being fertilized by sperm, thus, conception is taking place. However, due to LPD, the conceptus is unable to implant and is lost during menstruation. Many women with this disorder are quite often never aware that conception has occurred.

LPD results in mistiming of the menstrual and ovulatory cycles, which must work together for conception/pregnancy success. In cases of LPD, the uterine lining fails to become sufficient for a sustained pregnancy.

Also related: luteinized unruptured follicle (LUF) in which a relatively mature follicle receives just enough luteinizing hormone to cause progesterone production, but not enough to cause egg release by the follicle. Common in oligomenorrhea and possibly endometriosis, the LUF in essence behaves like a corpus luteum, producing progesterone and "faking ovulation."