O30.01

Twin pregnancy, monochorionic/monoamniotic

Header / non-billable

This code does not map to a risk-adjusting HCC in the loaded models.

Coding notes

Excludes 1 never coded together · Excludes 2 may co-exist

This code · O30.01
Excludes 1

conjoined twins (O30.02-)

Synonyms

Twin pregnancy, one placenta, one amniotic sac

Inherited from O30Multiple gestation
Code also

any complications specific to multiple gestation

Inherited from chapter 15Pregnancy, childbirth and the puerperium
Excludes 1

supervision of normal pregnancy (Z34.-)

Excludes 2

mental and behavioral disorders associated with the puerperium (F53.-) obstetrical tetanus (A34) postpartum necrosis of pituitary gland (E23.0) puerperal osteomalacia (M83.0)

Use additional

code, if applicable, from category Z3A, Weeks of gestation, to identify the specific week of the pregnancy, if known.

Note

CODES FROM THIS CHAPTER ARE FOR USE ONLY ON MATERNAL RECORDS, NEVER ON NEWBORN RECORDS Codes from this chapter are for use for conditions related to or aggravated by the pregnancy, childbirth, or by the puerperium (maternal causes or obstetric causes) Trimesters are counted from the first day of the last menstrual period. They are defined as follows: 1st trimester- less than 14 weeks 0 days 2nd trimester- 14 weeks 0 days to less than 28 weeks 0 days 3rd trimester- 28 weeks 0 days until delivery

Official Guidelines for O30.01

FY 2026 ›

Sections that reference O30.01

Sections whose FY 2026 text names O30.01, its O30 category, or a range containing it — the chapter guidance above is the authoritative source.