from rupturing syphilis bacteria. Pregnancy Penicillin is an effective treatment for syphilis in pregnancy but there is no agreement on which dose or route of delivery is most effective. Epidemiology In 2012, about 0.5% of adults were infected with syphilis, with 6 million new cases. In 1999, it is believed to have infected 12 million additional people, with greater than 90% of cases in the developing world. It affects between 700,000 and 1.6 million pregnancies a year, resulting in spontaneous abortions, stillbirths, and congenital syphilis. During 2015, it caused about 107,000 deaths, down from 202,000 in 1990. In sub-Saharan Africa, syphilis contributes to approximately 20% of perinatal deaths. Rates are proportionally higher among intravenous drug users, those who are infected with HIV, and men who have sex with men. In the United States about 55,400 people are newly infected each year. In the United States as of 2020, rates of syphilis have increased by more than threefold; in 2018 approximately 86% of all cases of syphilis in the United States were in men. African Americans accounted for almost half of all cases in 2010. As of 2014, syphilis infections continue to increase in the United States. Syphilis was very common in Europe during the 18th and 19th centuries. Flaubert found it universal among nineteenth-century Egyptian prostitutes. In the developed world during the early 20th century, infections declined rapidly with the widespread use of antibiotics, until the 1980s and 1990s. Since 2000, rates of syphilis have been increasing in the US, Canada, the UK, Australia and Europe, primarily among men who have sex with men. Rates of syphilis among US women have remained stable during this time, while rates among UK women have increased, but at a rate less than that of men. Increased rates among heterosexuals have occurred in China and Russia since the 1990s. This has been attributed to unsafe sexual practices, such as sexual promiscuity, prostitution, and decreasing use of barrier protection. Left untreated, it has a mortality rate of 8% to 58%, with a greater death rate among males. The symptoms of syphilis have become less severe over the 19th and 20th centuries, in part due to widespread availability of effective treatment, and partly due to virulence of the bacteria. With early treatment, few complications result. Syphilis increases the risk of HIV transmission by two to five times, and coinfection is common (30–60% in some urban centers).