Hi,
I checked in Guiness book of records and found out that the greatest (officially recorded) number of children produced by one mother is 69.  She was the 1st wife (out of 2 wives) of Feodor Vassilyev (1707-1782), a peasant from Shuya (a village located some 150 miles east of Moscow).  In 27 confinements she gave birth to: 16 pairs of twins, 7 sets of triplets and 4 sets of quadruplets.  The children, were born in the period between 1725 to 1765.
Best regards,