http://www.medicinenet.com/miscarriage_causes_and_symptoms/article.htmhttp://www.reproductivewellness.com/causes-of-recurrent-miscarriages/A miscarriage is the spontaneous loss of a pregnancyfrom conception to 20 weeks' gestation. The term stillbirth refers to the death of a fetus after 20 weeks' gestation. Miscarriage is sometimes referred to as spontaneous abortion, because the medical term abortion means the ending of a pregnancy, whether intentional or unintentional. Most miscarriages occur in the first trimester of pregnancy, between the 7th and 12th weeks of pregnancy What causes miscarriage?
The majority of miscarriages are believed to be caused by genetic problems in the embryo that would prevent a baby from developing normally and surviving. These fatal genetic errors typically are not related to genetic problems in the mother.
In other cases, certain illnesses or medical conditions can cause miscarriage and may increase the risk of miscarriage. Mothers who have diabetesor thyroid diseaseare at increased risk of miscarriage. Infections that spread to the placenta, including some viral infections, can also increase the risk of miscarriage.
In general, risk factors for miscarriage include the following:
Older maternal age
Cigarette smoking(>10 cigarettes/day)
Moderate to high alcohol consumption
Trauma to the uterus
Radiation exposure
Previous miscarriage
Maternal weight extremes (BMI either below 18.5 or above 25 kg/m2

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