Recently Mis Carried, A Trip To The Hospital Days Before

Recently mis carried, a trip to the hospital days before my miscarriage was brought on my a persistent groin ache moving from left to right. Early scan showed no sac and the following days bleeding and cramps started and it was confirmed my hcg levels had halved in 48 hours. What could have been the cause of this groin pain? It is still lingering on now every now and then, does suggest underlying issues? I have mentioned to hospital and no explanation given yet.