condition-guides

Luteal Phase Defect: Causes, Symptoms, and How to Identify

Luteal phase defect (LPD) means inadequate progesterone after ovulation — causing a short luteal phase, implantation failure, or early pregnancy loss. Here's

The luteal phase is the part of the menstrual cycle that most directly determines fertility — it's when the endometrium prepares for implantation, and when early pregnancy depends entirely on progesterone to continue. A defect in luteal phase function is a relevant issue for anyone trying to conceive and a window into broader cycle health for those who aren't. The Core Problem After ovulation, the ruptured follicle becomes the corpus luteum, which produces progesterone. Progesterone does several things: 1. Transforms the endometrium from a proliferative state to a secretory state (receptive to implantation) 2. Maintains the uterine lining long enough for implantation to occur (6–10 days post ovulation) 3. If pregnancy occurs, the corpus luteum is maintained by hCG and continues progesterone production until the placenta takes over In luteal phase defect (LPD), the corpus luteum produces inadequate progesterone — either insufficient levels, insufficient duration, or both. The result: the endometrium may not develop fully for implantation, or may shed (menstruation) before implantation can be completed. The Cycle Phase Cascade LPD is downstream of ovulation quality. The corpus luteum