Risk factors for miscarriage include an older mother or father, previous miscarriage, exposure to tobacco smoke, obesity, diabetes, and drug or alcohol use, among others. In those under the age of 35 the risk is about 10% while it is about 45% in those over the age of 40. Risk begins to increase around the age of 30. About 80% of miscarriages occur in the first 12 weeks of pregnancy (the first trimester). The underlying mechanism in about half of cases involves chromosomal abnormalities. Other conditions that can produce similar symptoms include an ectopic pregnancy and implantation bleeding. Diagnosis of a miscarriage may involve checking to see if the cervix is open or closed, testing blood levels of human chorionic gonadotropin (hCG), and an ultrasound. Ultrasound is an oscillating sound pressure wave with a frequency greater than the upper limit of the human hearing range. Ultrasound is thus not separated from 'normal' (audible) sound by differences in physical properties, only by the fact that humans cannot hear it. Although this limit varies from person to person, it is approximately 20 kilohertz (20,000 hertz) in healthy, young adults. Ultrasound devices operate with frequencies from 20 kHz up to several gigahertz. Ultrasound is used in many different fields. Ultrasonic devices are used to detect objects and measure distances. Ultrasonic imaging (sonography) is used in both veterinary medicine and human medicine. In the nondestructive testing of products and structures, ultrasound is used to detect invisible flaws. Industrially, ultrasound is used for cleaning and for mixing, and to accelerate chemical processes. Animals such as bats and porpoises use ultrasound for locating prey and obstacles. Prevention is occasionally possible with good prenatal care. This may involve avoiding drugs and alcohol, infectious diseases, and radiation. No specific treatment is usually needed during the first 7 to 14 days. Most women will complete the miscarriage without interventions. Occasionally the medication misoprostol or a procedure known as dilation and curettage (D&C) is required to remove the failed pregnancy. Women who are rhesus negative may require Rho(D) immune globulin. Pain medication and emotional support may be beneficial. Miscarriage is the most common complication of early pregnancy. Among women who know they are pregnant, the miscarriage rate is roughly 10% to 20% while rates among all conceptions is around 30% to 50%. About 5% of women have two miscarriages in a row. |