The most common causative organism of puerperal sepsis is:

Puerperal sepsis refers to infection of the genital tract occurring after childbirth. The most common pathogen is Streptococcus pyogenes (Group A Streptococcus), which spreads rapidly and can lead to septicemia and toxic shock syndrome. Risk factors include prolonged labor, repeated vaginal examinations, poor aseptic technique, and retained placental fragments. Early treatment with broad-spectrum antibiotics is essential.