Luteal phase deficiency is usually a problem of inadequate progesterone production associated with inadequate ovarian follicular development. The hypothesis that luteal phase deficiency results from an abnormal secretion pattern of luteinizing hormone (LH) was tested in these women. To this end, the early follicular LH secretion pattern in four women with luteal phase deficiency was characterized and compared with patterns in normal women. Blood samples were obtained through indwelling catheters every ten minutes for eight hours (10 am to 6 pm), and plasma levels of LH and FSH were measured. Luteinizing hormone and FSH secretion profiles were analyzed for pulse frequency, amplitude, and mean plasma level. A significantly greater LH pulse frequency in women with luteal phase deficiency was observed when compared with the frequency in normal controls (luteal phase deficiency, 10.5 pulses/eight hours; normal, 5.2 pulses/eight hours;P≤·05). The mean FSH concentration was less in the women with luteal phase deficiency, but the level was not significant. These data suggest that the abnormal LH secretion pattern observed in women with luteal phase deficiency is responsible for their inadequate luteal phase progesterone secretion and their infertility.