Hi,my Wife Has Been Having Miscarriage About 4-5 Times. And

Hi,my wife has been having miscarriage about 4-5 times. And a doctor introduce primolut which she took 3 days after she tested positive to pregnant again & she will take it twice a week for period of time but 2 days after d first primolut injectionshe see small bleeding again. How dangerous is this to the pregnancy & does it still safe?