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Approximately 15–25% of recognized pregnancies end in miscarriage. However, many miscarriages often occur before a woman even knows she is pregnant.
Over time, chronic hepatitis B virus and hepatitis C virus infections can progress to advanced liver disease, liver failure, and hepatocellular carcinoma. Unlike other forms, more than 80% of hepatitis C infections become chronic and lead to liver disease. When combined with hepatitis B, hepatitis C now accounts for 75% percent of all cases of liver disease around the world. Liver failure caused by hepatitis C is now leading cause of liver transplants in the United States.
The most destructive flu epidemic of all times in recorded history occurred in 1918, with approximately 20 million deaths worldwide.
In 1864, the first barbiturate (barbituric acid) was synthesized.
The Babylonians wrote numbers in a system that used 60 as the base value rather than the number 10. They did not have a symbol for "zero."