The first trimester of pregnancy can see a variety of factors leading to abortion (miscarriage). Common causes include: Chromosomal Abnormalities: Genetic issues in the embryo are the most frequent cause, often preventing normal development. Hormonal Imbalances: Insufficient progesterone can affect the uterine lining and embryo implantation. Uterine Abnormalities: Structural issues, such as fibroids or an abnormal shape of the uterus, can interfere with implantation and growth. Infections: Certain infections, such as bacterial vaginosis or sexually transmitted infections, can increase miscarriage risk. Chronic Health Conditions: Conditions like diabetes, thyroid disorders, and autoimmune diseases can impact pregnancy viability. Lifestyle Factors: Smoking, excessive alcohol use, and drug use can contribute to miscarriages. Age: Advanced maternal age can increase the risk of chromosomal abnormalities. Physical Trauma: Significant physical injury can potentially lead to miscarriage.