Why Did I Have a Miscarriage?

Miscarriage is very common, happening in anywhere from 10–20 percent of all known pregnancies, according to the Mayo Clinic. In an original survey (opens in new tab) Marie Claire conducted in partnership with SurveyMonkey (opens in new tab), 25 percent of women reported experiencing at least one miscarriage.

If you've had a miscarriage, know this: You didn't cause it by lifting a heavy object or exercising too intensely. Neither of those things lead to pregnancy loss. Nor does flying, stress, or sex. Fertility expert Aaron K. Styer, M.D. (opens in new tab), reproductive endocrinologist and co-medical director of CCRM Boston, assures us that the majority—more than 61 percent, according to one study—of miscarriages occur when the embryo has an abnormal number of chromosomes. In patients undergoing IVF, a form of preimplantation genetic testing for aneuploidy (opens in new tab) (PGT-A or PGS) called comprehensive chromosomal screening (CCS) can reduce the risk of miscarriages by looking at all pairs of chromosomes for any abnormal pairings. In this treatment, a small number of cells are taken from the outside of an embryo and tested to determine if it has the correct number of chromosomes before being transferred into the uterus.

The risk of miscarriage does increase with maternal age (due to the raised risk of chromosomal abnormalities). Certain chronic medical conditions and hormonal imbalances can also play a role.

Bear in mind: One miscarriage alone doesn’t immediately indicate a fertility issue. In fact, only 1 to 2 percent  (opens in new tab)of women will have two or more miscarriages. If you have two miscarriages in your attempt to get pregnant, go ahead and schedule an appointment with a fertility specialist to see if there might be a diagnosable reason—and treatment.

Still have questions about getting pregnant? Check out our fertility FAQ here (opens in new tab).

Editors’ note: We use the terms “woman” and “female” in this article to refer to people with internal reproductive organs; however we understand that not everyone with internal reproductive organs identifies as a woman or a female. We use the terms “man” and “male” to refer to people with external reproductive organs; however we understand that not everyone with external reproductive organs identifies as a man or a male.