How far can female fertility be extended?

Modern medicine is already allowing women to have children far later in life than their ancestors, but how far can female fertility really be extended?

Pregnancy after 40, IVF: CDC data shows more women delay having babies

PCOS (Polycystic Ovary Syndrome), LLU Fertility & IVF

What happens to a woman's fertility as she gets older? Does it decrease? If so, when does it start happening? How much can it go down from one year to another until

Fertility charting

Natural Fertility: The Essential Guide to Improving Your Fertility

Why do so many people have fertility issues nowadays? - Quora

Extending the Biological Clock - Reproductive Partners Fertility Center - San Diego

Popular Health Claims, Such as a Woman's Fertility Dropping at Age 30, Are Wildly Overblown

Risks of Hormonal Contraception After Age 40

How far can female fertility be extended?

12 Possible Risk Factors or Signs You Can't Get Pregnant