I have done a lot of research on this subject. This does not mean that most pregnancies after age 40 (actually, after age 37 according to my sources) will result in children born with Down Syndrome or other chromosomal problems; instead, most "old eggs" are never able to be fertilized at all, resulting in "failed cycles" or miscarriages. At age 45, there is a 1 in 12 chance of having a pregnancy with a child with Down Syndrome - not bad odds, I agree. However - most are never able to conceive AT ALL.
I have a friend who had several failed IVF cycles and was told by her fertility specialist that "old eggs" become a serious problem starting in the late thirties. She was 39, and he advised her to use donor eggs to increase her chances!
Therefore I DON'T believe for a minute that this 65-year-old quad mother-to-be had her youngest daughter at age 55 "naturally", i.e., without using IVF with donor eggs. Especially after watching the "exclusive interview" with the TV station RTL; she never admits it, of course, but the child does not resemble her at all. (See for yourself.)
In addition, it's striking how naive the woman appears to be... and clueless regarding the responsibility of raising quads - by herself.
She had better hope the media circus continues and finances it for her (Octomom had hoped for the same, and we know how that turned out).