Late implantation can result in a gestational sac by about 10 days at the latest.
Early blastocysts are formed 72 hours after fertilization, early blastocysts enter the uterine cavity 4 days after fertilization, early blastocysts develop into late blastocysts about 6 days after fertilization, and late blastocysts implant in the uterine lining and implantation occurs about 7 days after fertilization. The late blastocysts implant in the endometrium and implantation occurs at about 7 days after fertilization.
The gestational sac and yolk sac can be detected by ultrasound 4 weeks after fertilization, and the embryonic tissue can be seen at 5 weeks, but the time may vary according to individual’s physique and lifestyle.
If there is no gestational sac within the corresponding time, it is recommended to go to the hospital to clarify the cause of the disease and treat it under the guidance of the doctor, so as to avoid delaying the condition.