Chorioamnionitis, unspecified trimester, fetus 3

This code indicates an inflammation of the fetal membranes (chorion and amnion) and amniotic fluid, occurring at an unspecified point during the pregnancy, specifically affecting the third fetus in a multiple gestation. Chorioamnionitis is typically caused by a bacterial infection ascending from the vagina.

Apply this code when documentation confirms chorioamnionitis in a multifetal pregnancy where the specific trimester is not recorded, and the condition is attributed to the third fetus. This diagnosis is often supported by clinical signs such as maternal fever, uterine tenderness, foul-smelling amniotic fluid, and fetal tachycardia.

• Ensure the documentation clearly identifies the affected fetus as the "third fetus" in a multiple gestation.
• Do not use this code if the trimester is specified; instead, select the appropriate trimester-specific code (O41.121-, O41.122-, O41.123-).
• Code any associated maternal infections or fetal conditions separately, such as sepsis or premature rupture of membranes.