miscarriage

Spontaneous expulsion of a fetus from the womb before it is capable of independent survival. Miscarriage is believed to occur in 15% of pregnancies, often at such an early stage as to go unnoticed. Possible causes include fetal abnormality, abnormality of the uterus or cervix, infection, shock, underactive thyroid, and drug and alcohol use. The risk of miscarriage increases dramatically with age, from 5% for women under 30 to 50% for women in their mid-40s.