In those who are not improving with appropriate treatment, other complications such as an abscess should be considered.In 2015, about 11.8 million maternal infections occurred. In the developed world about 1% to 2% develop uterine infections following vaginal delivery. This increases to 5% to 13% among those who have more difficult deliveries and 50% with C-sections before the use of preventive 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, Hungarian physician Ignaz Semmelweiss decreased death from the disease in the First Obstetrical Clinic of Vienna from nearly 20% to 2% through the use of handwashing with calcium hypochlorite. Signs and symptoms
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. Causes
After childbirth, a womans genital tract has a large bare surface, which is prone to infection.
PPD 1–2: urinary tract infections risk factors include multiple catheterization during labor, multiple vaginal examinations during labor, and untreated bacteriuria. PPD 2–3: endometritis ( the most common cause ) risk factors include emergency cesarean section, prolonged membrane rupture, prolonged labor, and multiple vaginal examinations during labor. PPD 4–5: wound infection risk factors include emergency cesarean section, prolonged membrane rupture, prolonged labor, and multiple vaginal examinations during labor. PPD 5–6: septic pelvic thrombophlebitis risk factors include emergency cesarean section, prolonged membrane rupture, prolonged labor, and diffuse difficult vaginal childbirth. PPD 7–21: mastitis risk factors include nipple trauma from breastfeeding. Diagnosis
Puerperal fever is diagnosed with:

A temperature rise above 38 °C (100.4 °F) maintained over 24 hours or recurring during the period from the end of the first to the end of the 10th day after childbirth or abortion. (ICD-10)
Oral temperature of 38 °C (100.4 °F) or more on any two of the first ten days postpartum. (USJCMW)Puerperal fever  (from the Latin puer, male child (boy)), is no longer favored as a diagnostic category. Instead, contemporary terminology specifies:
the specific target of infection: endometritis (inflammation of the inner lining of the uterus), metrophlebitis (inflammation of the veins of the uterus), and peritonitis (inflammation of the membrane lining of the abdomen). the severity of the infection: less serious infection (contained multiplication of microbes) or possibly life-threatening sepsis (uncontrolled and uncontained multiplication of microbes throughout the blood stream).Endometritis is a polymicrobial infection.