O43.021 Fetus-to-fetus placental transfusion syndrome, first trimester

Billable ICD-10-CM code, FY2026.

Applies from O43 Placental disorders

Excludes2 (not included here)

• maternal care for poor fetal growth due to placental insufficiency (O36.5-)
• placenta previa (O44.-)
• placental polyp (O90.89)
• placentitis (O41.14-)
• premature separation of placenta [abruptio placentae] (O45.-)

MS-DRG index

Defines the logic of DRG(s) 817-819 in MDC 14.

Approximate ICD-9-CM (GEMs)

• 656.71 Other placental conditions, affecting management of mother, delivered, with or without mention of antepartum condition (approximate)
• 656.73 Other placental conditions, affecting management of mother, antepartum condition or complication (approximate)

Medicare Code Edits (MCE v43.1 (April 2026))

• Maternity diagnoses (age 9 through 64): Age conflict edit. These diagnoses are clinically expected only in patients age 9 through 64.

Code annotations containing back-references to O43.021

Back-references to O43.0

• Type 2 Excludes: O31 Complications specific to multiple gestation ("placental transfusion syndromes (O43.0-)")
• Type 1 Excludes: O36 Maternal care for other fetal problems ("placental transfusion syndromes (O43.0-)")

Nearby codes

• O43.011 Fetomaternal placental transfusion syndrome, first trimester
• O43.012 Fetomaternal placental transfusion syndrome, second trimester
• O43.013 Fetomaternal placental transfusion syndrome, third trimester
• O43.019 Fetomaternal placental transfusion syndrome, unspecified trimester
• O43.02 Fetus-to-fetus placental transfusion syndrome
• O43.021 Fetus-to-fetus placental transfusion syndrome, first trimester (this code)
• O43.022 Fetus-to-fetus placental transfusion syndrome, second trimester
• O43.023 Fetus-to-fetus placental transfusion syndrome, third trimester
• O43.029 Fetus-to-fetus placental transfusion syndrome, unspecified trimester
• O43.1 Malformation of placenta
• O43.10 Malformation of placenta, unspecified