Endometrial thickness of 1.6cm is normal. Endometrial thickness of 1.6cm is generally measured by ultrasonography. If the endometrial thickness reaches 1.6cm, it may be clinically in the post-ovulatory endometrial phenomenon. The thickness of the endometrium varies with the menstrual cycle, the thickness of the endometrium is not constant, before menstruation the endometrium is the thickest, it may reach 1.8cm, after menstruation as the endometrium peels off, the thickness of the endometrium may reach 0.4cm, so the thickness of the endometrium depends on the period of menstruation, depending on the period, the endometrium is changing accordingly.