Ultrasuperovulation is an advanced technique that significantly increases the number of oocytes produced by female mice. However, existing ultrasuperovulation techniques have a low fertilization rate, probably caused by the low incidence of sperm reaching the female's oocytes in vivo. Now, a group of researchers from Japan found that mating ultrasuperovulated mice with their breeding partner during or after ovulation can overcome this limitation and improve fertilization rates.
