infection of some part of the female reproductive (reproductive system disease) organs following childbirth (parturition) or abortion. Cases of fever of 100.4° F (38° C) and higher during the first 10 days following delivery or miscarriage are notifiable to the civil authority in most developed countries, and the notifying physician clarifies the diagnosis later, if possible. Puerperal infection is most commonly of 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 septicemia (blood poisoning), cellulitis (inflammation of cellular 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 patient. Abortions performed in unhygienic surroundings commonly result in puerperal fever.

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 welchii (inhabitants of the lower bowel); and, rarely and fatally, the bacillus of tetanus.

In the second half of the 20th century puerperal fever has become very rare in developed countries. The decline of the disease may be partly attributed to improved environmental conditions, better obstetrical care, and the use of sulfonamides and antibiotics. Another reason appears to be a lessening of the virulence or invasiveness of Streptococcus pyogenes. This organism is also the cause of scarlet fever, which over the same period has also declined markedly in severity and incidence.