Complex sentence: However, there are additional medical concerns for younger mothers, particularly those under 15 and those living in developing countries; for example, obstetric fistula is a particular issue for very young mothers in poorer regions.
Split into simpler sentences: However, there are additional medical concerns for younger mothers, particularly those under 15 and those living in developing countries. For example, obstetric fistula is a particular issue for very young mothers in poorer regions.