Maternal care for oth rhesus isoimmun, unsp tri, fetus 3

This code signifies maternal care for a pregnancy complicated by rhesus (Rh) isoimmunization, specifically when the mother is Rh-negative and has developed antibodies against Rh-positive fetal red blood cells, leading to potential hemolytic disease of the fetus and newborn. This particular code is used when the trimester is not specified in the documentation and refers to the third fetus in a multiple gestation.

Use this code when documentation indicates maternal care for Rh isoimmunization affecting the third fetus in a multiple pregnancy, and the specific trimester of care is not documented. This typically involves monitoring antibody titers, fetal well-being, and potential interventions like intrauterine transfusions. Documentation should clearly state "Rh isoimmunization," "third fetus," and the absence of a specified trimester.

• Ensure documentation explicitly identifies the third fetus in a multiple gestation to use this specific code.
• If the trimester is known, use the more specific O36.01- (first trimester), O36.02- (second trimester), or O36.03- (third trimester) codes.
• Always sequence this code as a secondary diagnosis, following the code for the obstetric encounter (e.g., Z3A.- for weeks of gestation).