Posted by Larry Grunfeld, MD on June 28, 19100 at 07:51:23:
In Reply to: q for dr. and/or anyone posted by elana on June 26, 19100 at 12:25:05:
The early embryo divides into the placenta and the fetal structures. The earliest fetal structure seen is the yolk sac. It can be seen as early as 34 days post LH surge. The fetus grows next to the yolk sac and ultimately separates from it. The presence of a normal yolk sac is likely to mean that a fetus will develop. Miscarriages often have abnormally large yolk sacs. The yolk sac is the organ from which the fetus derives its germ cells. These cells develop into sperm or eggs.
Larry Grunfeld, MD
: what is the yolk sac? is that the material that eventually becomes the fetus?