Please confirm that you are a health care professional
The link you have selected will take you to a third-party website. We do not control or have responsibility for the content of any third-party site.
The conceptus is still "guitar pick"–shaped at 21 days, and the hyperechoic embryo proper can be seen at the ventral aspect of the anechoic yolk sac.
Courtesy of Dr. Patricia Sertich.