LH (luteinizing hormone), luteinizing hormone (or luteinizing hormone), is a glycoprotein gonadotropin secreted by adenohypophysis cells that can promote follicle maturation and ovulation. Usually, ovulation test strips are used to test the LH level in a woman\’s urine to determine whether ovulation is approaching. In a complete menstrual cycle, LH levels change cyclically. The LH value will show an upward trend as it approaches the ovulation period. When LH reaches its peak, ovulation will generally occur within 24-48 hours. After ovulation is completed, LH value fell.