trigger shot contains HCG(human chorionic gonadotropin
), which helps in the maturation process and also in release of ovum.
generally after taking HCG in around 36 hours woman will ovulate.
according to some studies the success rate with ovulation induction
and trigger shot is around 50%,
but some studies showing only 16% success rate.
success with ovulation induction is subjective, depends on individual.
so, you do not bother about this and follow your doctor's instructions.