Q: Do you have any statistics on how frequently women miscarry? Also, what are the most common causes of miscarriage?
A: Unfortunately, miscarriages are much more common than most women think. About 15-20% of all pregnancies end in miscarriage. The vast majority of miscarriages are caused by genetic abnormalities, which means that the sperm and the egg did not fuse and divide properly.
The good news is that having one miscarriage does not increase your chances of having a second – indeed, when someone who has miscarried gets pregnant again, her chances of miscarriage are the same 15-20%. Even if a woman has had three miscarriages in a row, her chances of carrying the next pregnancy are still 75%.
If a woman has three miscarriages in a row, she be termed a “habitual aborter” (spontaneous abortion is the medical term for miscarriage.) If a woman does have three miscarriages, we recommend looking for other causes of a miscarriage. Occasionally, she may have a malformation inside her uterus, which is investigated with an x-ray of the lining of her uterus. She may not be ovulating well enough, and it would be measured her blood level of progesterone, or do a biopsy of the lining of her uterus, to check into it. Or, rarely, the woman or her partner themselves may have an undetected genetic abnormality, called a balanced translocation, and we would send blood tests on both partners to check chromosomes. A few women make antibodies against pregnancy, and there would check on these through some blood tests.
However, remember that these are much less common, and after one miscarriage, obstetricians would say just go for it – and you don’t have to wait too long to try. A cycle or two is quite sufficient to wait to conceive. Good luck.