Placentitis, unspecified trimester, fetus 1

This code signifies inflammation of the placenta occurring at any point during a pregnancy, specifically affecting the first fetus in a multiple gestation. Placentitis can be caused by various infectious agents and may lead to adverse pregnancy outcomes.

Apply this code when documentation confirms placental inflammation in a multifetal pregnancy, and the specific trimester is not recorded. This diagnosis is typically supported by pathological examination of the placenta or clinical signs and symptoms indicative of placental infection.

• Ensure documentation clearly specifies "fetus 1" in a multiple gestation to differentiate from other fetuses.
• If the trimester is known, use a more specific code from the O41.1- series (e.g., O41.12 for second trimester).
• Code any associated maternal conditions or infectious agents separately.