The probability of empty sac is less than 0.5%. Empty sacs usually occur due to poor egg quality, abnormal sperm quality, chromosomal abnormalities and other reasons, but the probability of empty sacs in normal people is very small, in addition, if a woman has a viral infection during pregnancy, it may also cause empty sacs, but the majority of pregnant women are able to appear normal yolk sacs, fetal heart.
If an empty sac occurs, it is important to go to the hospital in time to find out the cause. Couples during the preparation period should pay attention to maintain a good work and rest, avoid staying up late, which can reduce the probability of empty sacs, but also pay attention to the chromosome examination, eugenics examination before preparation for pregnancy.