الفهرس 
Luteal Phase DefectOnly 14 pages are availabe for public view
 |  | from | 110 |  |  |
| | | from | 110 | | |
Abstract
Luteal-phase defect has been defined as either a defect of progesterone secretion by the corpus luteum or a defect in endometrial response to hormonal stimulation, resulting in an inadequate endometrium for blastocyst implantation and subsequent pregnancy. The defect is estimated to affect 3–20% of the infertile population and 23–60% of women with recurrent miscarriage.
The main causes of luteal phase defect include Poor follicle production occurs in the first half of the cycle. In this case, the woman may not produce a normal level of FSH, or her ovaries do not respond strongly to the FSH, leading to inadequate follicle development. Because the follicle ultimately becomes the corpus luteum, poor follicle formation leads to poor corpus luteum quality. In turn, a poor corpus luteum will produce inadequate progesterone, causing the uterine lining to be adequately prepared for the implantation of a fertilized embryo. Ultimately progesterone levels may drop early and menses will arrive sooner than expected resulting in luteal phase defect. Premature failure of the corpus luteum can occur even when the initial quality of the follicle/corpus luteum is adequate. In some women the corpus luteum sometimes does not persist as long as it should. Here, initial progesterone levels at five to seven days past ovulation may be low; even if they are adequate, the levels drop precipitously soon thereafter, again leading to early onset of menses and hence a luteal phase defect. Failure of the uterine lining to respond can occur even in the presence of adequate follicle development and a corpus luteum that persists for the appropriate length of time. In this condition, the uterine lining does not respond to normal levels of progesterone. Therefore, if an embryo arrives and tries to implant in the uterus, the uterine lining will not be adequately prepared, and the implantation will most likely fail.