According to the Guinness Book of World's Records, what is the largest number of children born to one woman?

Mrs. Vassilyeva, wife of Feodor Vassilyev gave birth to 69 children over the 40 year period between 1725 - 1765. The Vassilyevas were a peasant family from Shuya, Russia, and Feodor has two wives. His first wife, whose name has been lost to history, had 27 confinements and gave birth to 16 pairs of twins, seven sets of triplets and four sets of quadruplets. All but two of them survived. She passed away in 1782 and Vassilyev remarried. His second wife was also unusually prolific, giving birth to six pairs of twins and two sets of triplets. He ended up siring 87 children. The first Mrs. Vassilyeva is believed to have a genetic predisposition to hyper-ovulate (release multiple eggs in one cycle), which significantly increases the chance of having twins or multiple children.

Although it seems overly fantastic and statistically unlikely, there is a significant amount of primary source evidence suggesting this story is true. The Monastery of Nikolsk recorded every birth and reported them to Moscow in 1782.

Although there have been numerous cases of very large families and, especially in modern times, many large families are the result of fertility medications. This woman gave birth to 69 children, all through natural means.