A 1.6*1.2 fluid dark area next to the gestational sac may be caused by subchorionic hemorrhage, preeclampsia, and implantation bleeding. 1. Subchorionic hemorrhage: Subchorionic hemorrhage may be caused by abnormal embryonic development, poor ovarian function or overwork, etc. When pregnant women have symptoms of subchorionic hemorrhage, they may show liquid dark area during ultrasound examination. 2. Pre-eclampsia: 1.6*1.2 fluid dark area next to the gestational sac is considered to be caused by pre-eclampsia, when pregnant women have progressive bleeding in the uterine cavity, it may lead to fluid dark area, if the gestational sac has fetal heart and buds, it can be treated with fertility preservation. 3. Bleeding on implantation: When the fertilized egg is implanted in the uterus, it may cause physiological bleeding, and some pregnant women may have a small amount of secretion in the vagina at the time of conception, and if the patient is accompanied by other uncomfortable symptoms, she should consult a doctor for examination in a timely manner. Pregnant women are advised to seek timely medical attention for blood HCG and progesterone tests, and if the values are low, they can be treated with fertility preservation.