If the pregnancy does not show, usually just show later, there are many reasons, related to the pregnancy week, women’s own abdominal wall conditions, the number of pregnancies and other factors, as long as there is no early pregnancy reaction suddenly disappeared, vaginal bleeding and fluid, abdominal pain and so on, do not need to worry about, and most of them are related to physiological reasons. Of course, we can’t completely exclude pathological reasons, you can go to the hospital for obstetric examination to observe the development of the fetus. Several common causes are as follows: First, physiological causes 1, pregnancy month is small, the uterus is not obvious, pregnant before the third month, the uterus has not been out of the pelvis, so the abdomen can not see the obvious bulge, if the belly bulge, should be the pregnant woman’s own abdominal fat accumulation; 2, taller people may be pregnant with other people later, because taller women pelvic cavity is wide and deep, so the uterine fundus out of the pelvic time late; 3, if a woman abdominal walls are thicker, the abdominal wall, the uterus can not be seen. If a woman’s abdominal wall is thicker, it is difficult to see the enlargement of the fetus in appearance, so she shows her pregnancy later; 4. Under the premise that other conditions are similar, a primigravida shows her pregnancy later than a menstruating woman, and the pelvic ligaments and abdominal skin of a menstruating woman are loosened, especially the height of the uterine fundus of a menstruating woman before the 24th week of pregnancy is higher than that of a primigravida woman obviously, and is sometimes greater than the height of the pregnancy week during the same period of time; 5. The position of the uterus may be more posterior, i.e., the uterus is posterior to the pregnancy. After the uterus enlarges, most of the uterus tilts towards the pelvis as well as grows posteriorly in the abdominal cavity, so it is not obvious in the abdominal display. Second, pathological reasons such as the existence of intrauterine fetal development retardation or amniotic fluid is low, the uterine volume is relatively small, the apparent pregnancy is not obvious. As long as the woman in the obstetrics ultrasound suggests that the size, growth and development of the fetus, each structure is in line with the gestational week, no other abnormalities, there is no need to worry too much, regular prenatal checkups can be done.