Forget about blame with miscarriage: its function is entirely natural

FOR more than a century, medical researchers have known that miscarriage is rarely preventable and is instead usually due to chromosomal abnormalities in an embryo. In recent decades, it has also become clear that miscarriage is very common: as many as one in five known pregnancies ends this way. That figure goes up as we get ever better at detecting pregnancy from its very first stages. It is now estimated that, among women in their early 20s, half of pregnancies end in miscarriage. This proportion rises with age.

No small effort has been made by …