Chorioamnionitis
A 30-year-old woman, gravida 2 para 1, was admitted 3 days ago at 30 weeks gestation with preterm premature rupture of membranes and managed expectantly. Today her temperature is 38.6 °C, pulse 120 beats/min, with marked uterine tenderness and foul-smelling vaginal discharge. Fetal heart rate baseline is 175 beats/min. Which of the following is the most likely diagnosis?
- A.Placental abruption
- B.Cervical incompetence
- C.ChorioamnionitisCorrect
- D.Onset of preterm labor
Explanation
Maternal fever with uterine tenderness, maternal tachycardia, fetal tachycardia and purulent or foul-smelling amniotic fluid after ruptured membranes is intra-amniotic infection, or chorioamnionitis. Once the membranes rupture the natural barrier to ascending vaginal flora is lost, so the risk of infection rises with the duration of rupture, which is why latency antibiotics are given and why serial monitoring of temperature, pulse, uterine tenderness and fetal heart rate is mandatory during expectant management. Chorioamnionitis is a clinical diagnosis and does not require amniocentesis in a typical case. Management is prompt delivery regardless of gestational age together with broad-spectrum intravenous antibiotics, usually ampicillin plus gentamicin, with anaerobic cover added for cesarean delivery. Placental abruption presents with painful vaginal bleeding and a tense tender uterus, but not with fever and purulent discharge. Cervical incompetence is painless cervical dilation in the mid trimester without infection. Preterm labor produces regular contractions and cervical change, not fever and foul discharge, although chorioamnionitis frequently triggers labor. Untreated infection risks maternal sepsis and neonatal pneumonia, sepsis and neurological injury.
Why each option
- A.
- Abruption causes painful bleeding with a tense tender uterus but not fever, purulent discharge or this infective picture.
- B.
- Cervical incompetence is painless mid-trimester dilation without fever, tenderness or discharge.
- C.
- Correct. Fever, uterine tenderness, maternal and fetal tachycardia and foul discharge after ruptured membranes define chorioamnionitis.
- D.
- Preterm labor is defined by regular contractions with cervical change and does not itself cause fever and foul-smelling discharge.
Reference: ACOG Committee Opinion No. 712, Intrapartum Management of Intraamniotic Infection (reaffirmed 2022)
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