For women of childbearing age, if menstruation is normally regular, a delay of up to one week is normal. The regulation of menstrual cycle is mainly influenced by the cycle of estrogen and progesterone secreted by the ovaries. In the first half of the menstrual cycle, the endometrium gradually thickens under the influence of elevated estrogen. After ovulation by the ovaries and entering the second half of the menstrual cycle, the endometrium continues to grow and thicken under the combined effect of estrogen and progesterone. When the hormone level retreats, the endometrium peels off and the onset of menstruation occurs. However, the ovarian hormone level will fluctuate appropriately when stimulated by external factors, resulting in early or delayed menstruation, usually within 1 week is normal, if the delay is longer, it will easily lead to the occurrence of menstrual disorders. In addition, in order to ensure the regularity of menstrual cycle, women should pay attention to maintain a regular life, increase nutrition and relaxation, which is conducive to the regulation of menstrual cycle.