It is more common for a woman to have a miscarriage than a baby, according to a study.
On average women can expect to have more miscarriages than children over their lives but many will be so early they go unnoticed.
This, says the scientist who wrote the study, is because of deadly genetic abnormalities in eggs which stop them ever developing into babies.
Experts say it is wrong to think of a miscarriage as a rare mistake, because it’s actually more common than a successful pregnancy.