What would cause a miscarriage if you were 8 weeks and had minor spotting but the baby showed normal heart-rate on an ultrasound just two hours before?

It's important to note that a miscarriage can occur for various reasons, and without a thorough medical evaluation, it's challenging to determine the exact cause. However, some potential factors could contribute to a miscarriage even after a normal heart-rate is observed on ultrasound:

Underlying Medical Conditions: Certain underlying medical conditions, such as uncontrolled diabetes, thyroid problems, or hormonal imbalances, can increase the risk of miscarriage.

Genetic Abnormalities: Chromosomal abnormalities or genetic defects in the developing embryo can lead to miscarriage.

Uterine Abnormalities: Structural issues in the uterus, such as a septum or fibroids, can interfere with the implantation and growth of the embryo.

Infections: Infections like sexually transmitted diseases (STDs) or certain viral or bacterial infections can cause inflammation and harm the developing pregnancy.

Immunological Issues: Sometimes, a woman's immune system may react against the pregnancy, leading to the production of antibodies that can affect the viability of the embryo.

Cervical Insufficiency: If the cervix (the opening to the uterus) is weak, it may not be able to hold the growing fetus, leading to a miscarriage.

Trauma or Injury: Physical trauma, accidents, or forceful impact on the abdomen can also increase the risk of miscarriage.

It's important to consult with a healthcare professional to understand the specific reason behind a miscarriage and receive appropriate guidance and support.