The gestational sac is the primitive placental tissue, which is the initial form of pregnancy. The slow development of the gestational sac in the 6th week of pregnancy may be due to preeclampsia, insufficient nutritional intake, chromosomal abnormalities and other reasons. 1. Pre-eclampsia: After pre-eclampsia to preserve the fetus, there can be a stage of progesterone deficiency leading to slow development of the gestational sac. 2. Inadequate nutritional intake: If the pregnant woman usually has a low intake of nutrients or picky eating, it will lead to nutritional deficiencies, resulting in the slow development of the gestational sac in the sixth week of pregnancy. 3. Chromosomal abnormalities: the slow development of the 6-week gestational sac can also be caused by chromosomal abnormalities, at this time the fetus may be arrested or miscarriage of the present. If a pregnant woman has a slow development of pregnancy sacs, it is recommended to consult a doctor in time, under the guidance of the doctor, improve the relevant examination, to clarify the cause of the disease, symptomatic treatment.