Q: How often does miscarriage happen?
A: Over 60% of early miscarriages are due to chromosomal anomalies in the embryo. An early miscarriage is one that occurs between 6 and 12 weeks of pregnancy, or in the first trimester of pregnancy.
Keep in mind, that there is nothing anyone could have done to prevent this.
Statistically speaking, in a study by The New England Journal of Medicine, 198 pregnancies were identified by an increase in the hCG level near the expected time of implantation. Of these, 22% ended before pregnancy was detected clinically.
The total rate of pregnancy loss after implantation (including clinically recognized spontaneous abortions) was 31%. Most of the 40 women with unrecognized early pregnancy losses had normal fertility since 95% of them subsequently became clinically pregnant within two years.
The New England Journal of Medicine - Volume 319:189-194 July 28, 1988 Number 4 Incidence of early loss of pregnancy AJ Wilcox, CR Weinberg, JF O'Connor, DD Baird, JP Schlatterer, RE Canfield, EG Armstrong, and BC Nisula