Empress Leopoldina of Brazil had seven children between April 4, 1819, and December 2, 1825. Seven children in six years and a half. Died in December 1826 after a miscarriage at the age of 29.
Empress Teresa Cristina of Brazil had four children between February 23, 1845, and July 19, 1848. Four children in three years and a half.
Princess Leopoldina of Saxe-Coburg and Gotha (neé Princess of Brazil) had four sons between May 19, 1866, and September 15, 1870. Four sons in four years and a half. Died in typhoid fever in February 1871 at the age of 23.
Princess Maria Elizabeth of Brazil had twelve children between June 6, 1938, and July 14, 1959. Twelve children in 21 years (the last pregnancy was with twins).