Postpartum infections, also known as childbed fever and puerperal fever, are any bacterial infections of the female reproductive tract following childbirth or miscarriage. Signs and symptoms usually include a fever greater than 38.0 °C (100.4 °F), chills, lower abdominal pain, and possibly bad-smelling vaginal discharge. It usually occurs after the first 24 hours and within the first ten days following delivery. Postpartum infections, also known as childbed fever and puerperal fever, are any bacterial infections of the female reproductive tract following childbirth or miscarriage. Signs and symptoms usually include a fever greater than 38.0 °C (100.4 °F), chills, lower abdominal pain, and possibly bad-smelling vaginal discharge. It usually occurs after the first 24 hours and within the first ten days following delivery. The most common infection is that of the uterus and surrounding tissues known as puerperal sepsis, postpartum metritis, or postpartum endometritis. Risk factors include Caesarean section (C-section), the presence of certain bacteria such as group B streptococcus in the vagina, premature rupture of membranes, multiple vaginal exams, manual removal of the placenta, and prolonged labour among others. Most infections involve a number of types of bacteria. Diagnosis is rarely helped by culturing of the vagina or blood. In those who do not improve, medical imaging may be required. Other causes of fever following delivery include breast engorgement, urinary tract infections, infections of an abdominal incision or an episiotomy, and atelectasis. Due to the risks following Caesarean section, it is recommended that all women receive a preventive dose of antibiotics such as ampicillin around the time of surgery. Treatment of established infections is with antibiotics, with most people improving in two to three days. In those with mild disease, oral antibiotics may be used; otherwise intravenous antibiotics are recommended. Common antibiotics include a combination of ampicillin and gentamicin following vaginal delivery or clindamycin and gentamicin in those who have had a C-section. In those who are not improving with appropriate treatment, other complications such an abscess should be considered. In 2015, about 11.8 million maternal infections occurred. In the developed world about one to two percent develop uterine infections following vaginal delivery. This increases to five to thirteen percent among those who have more difficult deliveries and 50 percent with C-sections before the use of preventative antibiotics. In 2015, these infections resulted in 17,900 deaths down from 34,000 deaths in 1990. They are the cause of about 10% of deaths around the time of pregnancy. The first known descriptions of the condition date back to at least the 5th century BCE in the writings of Hippocrates. These infections were a very common cause of death around the time of childbirth starting in at least the 18th century until the 1930s when antibiotics were introduced. In 1847, in Austria, Ignaz Semmelweiss through the use of handwashing with calcium hypochlorite decreased death from the disease from nearly twenty percent to two percent. Signs and symptoms usually include a fever greater than 38.0 °C (100.4 °F), chills, low abdominal pain, and possibly bad smelling vaginal discharge. It usually occurs after the first 24 hours and within the first ten days following delivery. After childbirth a woman's genital tract has a large bare surface, which is prone to infection. Infection may be limited to the cavity and wall of her uterus, or it may spread beyond to cause septicaemia (blood poisoning) or other illnesses, especially when her resistance has been lowered by a long labour or severe bleeding. Puerperal infection is most common on the raw surface of the interior of the uterus after separation of the placenta (afterbirth); but pathogenic organisms may also affect lacerations of any part of the genital tract. By whatever portal, they can invade the bloodstream and lymph system to cause sepsis, cellulitis (inflammation of connective tissue), and pelvic or generalized peritonitis (inflammation of the abdominal lining). The severity of the illness depends on the virulence of the infecting organism, the resistance of the invaded tissues, and the general health of the woman. Organisms commonly producing this infection are Streptococcus pyogenes; staphylococci (inhabitants of the skin and of pimples, carbuncles, and many other pustular eruptions); the anaerobic streptococci, which flourish in devitalized tissues such as may be present after long and injurious labour and unskilled instrumental delivery; Escherichia coli and Clostridium perfringens (inhabitants of the lower bowel); and Clostridium tetani. Causes (listed in order of decreasing frequency) include endometritis, urinary tract infection, pneumonia/atelectasis, wound infection, and septic pelvic thrombophlebitis. Septic risk factors for each condition are listed in order of the postpartum day (PPD) on which the condition generally occurs.