The most prevalent cause of pregnancy loss is a chromosomal abnormality that prevents the fetus from developing correctly. A miscarriage might also be caused by aberrant hormone levels in the mother, such as thyroid hormone. Diabetes that is uncontrolled during pregnancy can also lead to a miscarriage. Miscarriages can also be caused by factors such as infections (especially HIV/AIDS), poor nutrition, and certain medications. However, these are relatively rare causes of miscarriage. Most miscarriages occur before the 12th week of gestation and are called early miscarriages. After this point, a small number of miscarriages are due to genetic abnormalities present in the embryo. These should not be considered normal losses and need to be investigated by a professional diagnosing laboratory. Some women who have had multiple miscarriages may want to consider genetic testing to identify any potential medical conditions or inherited mutations that could be responsible. For example, women with a family history of genetic diseases such as cancer may want to know about genetic mutations in their DNA that could increase their risk for other illnesses. Women who have had a prior fetal death should be warned that future miscarriages may be due to autoimmune disorders that can harm both the mother and her child. Therefore, regular checkups are recommended for both mothers and children after such events so that any problems can be detected early.