What is the most common cause of pregnancy loss?

Chromosomal abnormalities are identified as the most common cause of pregnancy loss, particularly in the first trimester. This is primarily due to the fact that many pregnancies that result in miscarriage involve embryos with an abnormal number of chromosomes, a condition known as aneuploidy. Such abnormalities can arise from errors during cell division, resulting in genetic issues that prevent the embryo from developing normally. Even in cases where an embryo does implant successfully, these chromosomal issues often result in early pregnancy loss, which is why they are deemed the leading cause of miscarriage.

While maternal age, infections, and environmental factors can contribute to the risk of pregnancy loss, chromosomal abnormalities remain the most prevalent underlying cause. As women age, the likelihood of chromosomal abnormalities increases, which can contribute to miscarriage rates, but the abnormalities themselves are the direct trigger for many of these losses.