It’s a difficult area because Islamic marriages, regardless of the age of the bride, are often conducted in private homes by people who are not legally qualified to conduct them; therefore such marriages are not registered and are not legally recognised. If a girl is abused (which in my opinion every child bride is) the perpetrator would be prosecuted, but since secrecy surrounds underage marriages, it’s unlikely that such abuse, and the physical injury caused, would ever be brought to the attention of the authorities.
There are thousands of girls being subjected to FGM, but again, because that horrendous practice is carried out secretly, and mainly during a trip abroad, only now are we beginning to acknowledge that a serious problem exists.
http://www.bbc.co.uk/news/uk-23982767