Twin pregnancy, dichorionic/diamniotic, third trimester

This code signifies a twin gestation where each fetus has its own chorion and amnion, indicating two separate placentas and amniotic sacs. This specific code applies when the pregnancy has reached the third trimester.

Use this code for a pregnant patient carrying dichorionic/diamniotic twins who is in her third trimester of gestation. Documentation must clearly specify a twin pregnancy, dichorionic/diamniotic placentation, and a gestational age consistent with the third trimester (typically 28 weeks and beyond).

• Ensure documentation explicitly states "dichorionic/diamniotic" for accurate coding; "fraternal twins" often implies this but direct confirmation is preferred.
• Verify the gestational age to confirm the third trimester; avoid using this code for earlier trimesters.
• This code is typically a secondary diagnosis, following the primary code for the pregnancy itself (e.g., Z3A.xx for weeks of gestation).