Symptoms of Luteal Phase Defect
Luteal phase defect (LPD), or luteal insufficiency, occurs when the luteal phase is shorter than normal, progesterone levels during the luteal phase are below normal, or both. LPD is believed to interfere with the implantation of embryos.The lactational amenorrhea method of birth control works primarily by preventing ovulation, but is also known to cause LPD.

LPD is a spectrum. There is unruptured luteinized follicle syndrome (ULFS), short luteal phases that are, for example, nine days long, and follicular non-responsiveness to hCG. The second two varieties can be stabilized by taking high-dose progesterone suppositories or injections until one gets a positive pregnancy test, and then continuing for another 8–10 weeks until the placenta is self-sufficient. Some people have seen normalization with a high dose of vitamin B6. Symptoms of luteal phase defect may include:

-- Difficulty getting pregnant
-- Spotting in between periods
-- More frequent periods
-- Miscarriage