Impaired follicular growth and abnormal luteinizing hormone surge in luteal phase defect.

LH surge causes the developed follicle to ovulate. At the textbook, LH surge is shown as a sharp peak, but actual surges are sometimes low levels and/or last for days. The peak and secretion width of LH were examined by urinalysis. The results showed that when the follicle development is delayed, LH surge is blunt and prolonged, and the function of the corpus luteum is reduced.

Fertil.Steril