The chest is not distended on the 10th day of transferring blastocysts may be caused by physiological reasons, or may be caused by the failure of the transfer. 1 physiological reasons: the transfer of blastocysts refers to in vitro fertilization – embryo transfer technology, is a kind of assisted reproductive technology, to be operated by professional doctors. After successful embryo implantation, due to the rise in estrogen and progesterone levels in the body, some pregnant women may experience breast swelling and pain, but there are a few pregnant women may not have any reaction, which is a normal physiological phenomenon. 2. Failure of implantation: the feeling of no breast swelling on the 10th day after embryo implantation may also be caused by the failure of embryo implantation after implantation, which can be combined with blood or urine HCG test to confirm whether the implantation is successful or not. When the test result is negative, you can observe temporarily under the guidance of your doctor and have regular checkups to see how the embryo is developing. If the chest is not distended on the 10th day of blastocyst transfer, you can go to the hospital for relevant examination and treatment under the guidance of the doctor.