Up to 15% of clinically recognised pregnancies end in miscarriage and possibly 50% of all conceptions end within the first 12 weeks of pregnancy.
Approximately half of the women do not realise they were even pregnant.
Advanced maternal age is often associated with an increased risk of miscarriage and there are many causal reasons for this correlation.
Miscarriage may be the result of poor egg quality, which may be inefficient metabolically, genetically or chromosomally, or defective spermatozoa, or indeed the embryo in its early development may encounter problems.
The other major cause, of course, is the uterus, which could have anatomical, immunological or inflammatory problems.
Some women may have several consecutive miscarriages, and in this case we use the term recurrent miscarriage.
In either case, there are diagnostic tests and protocols to be applied to aid the couple in achieving a live birth.