Miscarriage represents a profound loss, and for many who experience one, the immediate concern shifts to the possibility of conceiving a healthy pregnancy in the future. Miscarriage is defined as the spontaneous loss of a pregnancy before 20 weeks of gestation, affecting approximately 10% to 20% of known pregnancies. Infertility is medically defined as the inability to conceive after one year of unprotected intercourse, or six months for women over the age of 35. Understanding the relationship between these two conditions is important.
Understanding the Link: Does Miscarriage Directly Cause Infertility?
A single miscarriage does not typically cause infertility, and most people who experience one or two losses go on to conceive successfully. The loss is often due to a random chromosomal abnormality in the embryo, which is a one-time event that does not affect future fertility potential. Studies show that a large majority of women, even those who have had two or more losses, eventually achieve a successful pregnancy.
Experiencing a miscarriage is often viewed by fertility specialists as evidence that a woman can become pregnant, which is an encouraging sign. Some research suggests that the highest post-miscarriage fertility rates occur in the three to six months following the loss, possibly due to a biological readiness in the body. The risk of having a subsequent miscarriage after one loss is only slightly higher, at about 20%, and for most, the outcome is a healthy baby.
The primary concern is not the miscarriage itself, but whether the loss points to an existing underlying health issue. Only a small percentage of women, about 1%, experience recurrent pregnancy loss, which is defined as two or more consecutive miscarriages. In these cases, the repeated losses may signal an issue that could also interfere with the ability to conceive, meaning both the miscarriage and the difficulty conceiving are symptoms of the same problem.
Scarring and Procedural Complications
In very rare instances, the medical management of a miscarriage can introduce a complication that affects future conception. When a miscarriage is incomplete, a surgical procedure called Dilation and Curettage (D&C) may be performed to remove remaining tissue from the uterus. This procedure involves dilating the cervix and gently scraping or suctioning the uterine lining.
The scraping of the uterine wall, particularly if performed aggressively or repeatedly, can sometimes damage the basal layer of the endometrium. This damage can lead to the formation of scar tissue inside the uterus, a condition known as Asherman’s Syndrome. Asherman’s Syndrome is a rare complication, but it is a potential cause of infertility because the adhesions can prevent an embryo from successfully implanting or cause menstrual irregularities.
Researchers estimate that over 90% of Asherman’s Syndrome cases occur after pregnancy-related D&C procedures, though the overall risk remains low. The scar tissue physically reduces the space within the uterine cavity and can impair the function of the endometrium, which is necessary to support a pregnancy. Treatment for this condition typically involves hysteroscopic surgery to remove the scar tissue, which can often restore fertility.
Shared Conditions Affecting Both Pregnancy Loss and Conception
When a person experiences both miscarriage and subsequent infertility, it is often because a single underlying health condition disrupts both the ability to conceive and sustain a pregnancy. These shared factors are the focus of investigation during recurrent loss. One common category involves hormonal imbalances, such as poorly controlled diabetes, thyroid disorders, or polycystic ovary syndrome (PCOS), which can disrupt the reproductive cycle.
Anatomical issues in the uterus can also cause both problems, acting as a barrier to successful implantation and development. Examples include a uterine septum, which is a wall of tissue dividing the uterus, or large uterine fibroids that distort the cavity. Correcting these structural abnormalities, such as surgically removing a septum, can often resolve the issue.
Another significant group of causes relates to genetic and autoimmune factors. Chromosomal abnormalities in either partner, such as a balanced translocation, can lead to the creation of embryos with an unbalanced genetic makeup, causing repeated losses. Autoimmune disorders, most notably Antiphospholipid Syndrome (APS), cause the body to produce antibodies that increase the risk of blood clotting, which can interfere with the blood flow to the developing placenta. Identifying and treating these specific conditions is the key to overcoming both the recurrent loss and the difficulty conceiving.
Seeking Evaluation and Specialized Care
Knowing when to seek specialized care from a reproductive endocrinologist or fertility specialist is an important step. While one early miscarriage typically does not require extensive investigation, an evaluation is strongly recommended after two or more consecutive losses. If a woman is over the age of 35, many specialists recommend starting an evaluation after just one miscarriage combined with six months of difficulty conceiving, due to age-related decline in egg quality.
The initial evaluation typically involves a series of diagnostic tests designed to uncover underlying issues. These may include blood work to check for hormonal imbalances (such as thyroid function and prolactin levels) and to screen for Antiphospholipid Syndrome. A hysteroscopy or specialized ultrasound may also be used to visualize the inside of the uterus and check for anatomical issues or scarring.
Genetic screening, or karyotyping, of both partners can also be performed to identify any chromosomal translocations contributing to the recurrent losses. This comprehensive evaluation allows for the identification of a specific cause in many cases, leading to a targeted treatment plan and improving the chances of a future successful pregnancy.