Are Hormonal Injections Best For Enhancing Uterus Growth?

My eight year old girl , her weight is 22kgs , her height is 3 feet 4 inches,had a UTI twice this month, i took her for lower abdomen's ultrasound prescribed by her pediatrician n found that her ovaries r fine but her uterus is equal to a new born baby's size, infact uterus just had margins nothing else . Dr said i need to do her MRI or get her some hormonal injections for enhancing her uterus growth ? Is that correct procedure ? should i go for it ? N what does that all mean ?