Mat care chromosomal abnlt in fetus, Trisomy 21, fetus 4

This code indicates that a pregnant patient is receiving medical care due to a suspected or confirmed diagnosis of Trisomy 21 (Down syndrome) in the fourth fetus of a multiple gestation pregnancy. This care typically involves monitoring the fetal well-being and planning for potential complications associated with Trisomy 21.

Use this code when documentation specifies maternal care for a fetus diagnosed with or suspected of having Trisomy 21, and it is explicitly identified as the fourth fetus in a multifetal pregnancy. This applies to scenarios where diagnostic tests like amniocentesis or NIPT have indicated the chromosomal abnormality.

• Ensure the documentation clearly identifies the specific fetus (e.g., "fetus 4") when coding for multiple gestations.
• Do not use this code if the chromosomal abnormality is not Trisomy 21; other O35.1 subcategories exist for different abnormalities.
• Sequence this code as a secondary diagnosis following the primary reason for the encounter if the maternal care is not the sole focus.