Miscarriage is defined as the spontaneous loss of a pregnancy before the 20th week of gestation. It is a common event, affecting approximately 10% to 20% of known pregnancies, though the actual rate is likely higher since many losses occur before pregnancy is confirmed. This loss is a source of anxiety, often raising concerns about the ability to conceive again. However, a single pregnancy loss does not cause infertility, which is the inability to become pregnant.
Miscarriage Does Not Cause Infertility
The vast majority of miscarriages occur due to issues with the specific embryo, not problems with the parent’s ability to sustain a future pregnancy. Most early losses, particularly those in the first trimester, are caused by random chromosomal or genetic abnormalities in the developing fetus. These abnormalities affect the embryo’s proper growth and development. They are usually non-recurrent, occurring by chance during fertilization, and are considered an isolated event rather than an indication of an underlying health condition.
Because the cause is often an isolated genetic error, the reproductive system remains unaffected and capable of achieving and carrying a healthy pregnancy. For individuals who have experienced one miscarriage, the risk of a future loss is only slightly elevated, remaining at about 20%. The majority of people who experience a single miscarriage go on to have successful subsequent pregnancies without medical intervention. This high likelihood of a positive outcome confirms that a single loss is not a predictor of long-term infertility.
Rare Complications That Can Impact Future Conception
While the miscarriage event itself rarely causes infertility, a few rare physical complications resulting from the loss or its management can create challenges for future conception. The most significant of these is Asherman’s Syndrome, a condition characterized by the formation of scar tissue, or intrauterine adhesions, inside the uterus. This scarring can interfere with the normal growth of the endometrium, the lining where a future embryo needs to implant.
Asherman’s Syndrome most often develops following Dilation and Curettage (D&C), a surgical procedure sometimes used to clear remaining tissue from the uterus after a miscarriage. This procedure involves scraping the uterine lining, and if the basal layer of the endometrium is damaged, scar tissue can form, causing the walls of the uterus to stick together. The resulting adhesions can lead to secondary infertility, implantation issues, or recurrent pregnancy loss.
Another rare complication that can impact the uterine environment is a severe uterine infection, known as endometritis, occurring following the miscarriage. Although infections are uncommon, they cause inflammation and damage to the endometrial lining, potentially leading to scarring and affecting the uterus’s ability to support a new pregnancy. Fortunately, both Asherman’s Syndrome and chronic endometritis are diagnosable and often treatable with hysteroscopic surgery, allowing for a return to normal reproductive function.
Differentiating Recurrent Miscarriage from Infertility
It is important to distinguish between infertility and recurrent pregnancy loss (RPL), as they represent different challenges. Infertility is defined as the inability to conceive after 12 months of unprotected intercourse for those under 35, or six months for those 35 and older. By contrast, individuals with recurrent pregnancy loss are able to conceive but experience two or more consecutive miscarriages, indicating an issue with maintaining the pregnancy.
Recurrent loss often signals an underlying maternal or paternal health condition that requires specialized investigation. These issues may include anatomical problems (such as a uterine septum or fibroids), endocrine disorders (like uncontrolled diabetes or thyroid dysfunction), or autoimmune conditions (like antiphospholipid syndrome). Clinicians recommend a full diagnostic workup, including blood tests and imaging, after a patient has experienced two consecutive losses to identify and manage these factors. Addressing these specific conditions can significantly improve the chance of carrying a subsequent pregnancy to term.