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ICD-10-CM 2027 diagnosis code

O34.01Maternal care for unspecified congenital malformation of uterus, first trimester

✓ Billable / specificMaternity · age 9–64Female only

O34.01 is a valid, billable ICD-10-CM code for maternal care for unspecified congenital malformation of uterus, first trimester. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.Short description: Maternal care for unsp congen malform of uterus, first tri

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About O34.01

O34.01 is the ICD-10-CM diagnosis code for maternal care for unspecified congenital malformation of uterus, first trimester. It belongs to category O34 (maternal care for abnormality of pelvic organs), block O30-O48 (maternal care related to the fetus and amniotic cavity and possible delivery problems) and chapter 15 (pregnancy, childbirth and the puerperium). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within O34.0 (maternal care for congenital malformation of uterus), O34.01 is specifically for maternal care for unspecified congenital malformation of uterus, first trimester. Related codes cover unspecified trimester (O34.00), second trimester (O34.02) and third trimester (O34.03).

Code first: any associated obstructed labor (O65.5).

Use an additional code for specific condition.

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 817 (Other Antepartum Diagnoses with O.R. Procedures with MCC, relative weight 2.0534), DRG 818 (Other Antepartum Diagnoses with O.R. Procedures with CC, relative weight 1.2942), DRG 819 (Other Antepartum Diagnoses with O.R. Procedures without CC/MCC, relative weight 0.7739), DRG 831 (Other Antepartum Diagnoses without O.R. Procedures with MCC, relative weight 1.1558), DRG 832 (Other Antepartum Diagnoses without O.R. Procedures with CC, relative weight 0.7585) and DRG 833 (Other Antepartum Diagnoses without O.R. Procedures without CC/MCC, relative weight 0.5002), in MDC 14 (Pregnancy, Childbirth and the Puerperium), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

The Medicare Code Editor treats this as a maternity diagnosis, expected only for patients age 9 through 64.

It is on the CMS list of diagnoses consistent only with female patients (the sex-conflict edit itself was retired in FY2025).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 654.01 (congenital abnormalities of uterus, delivered, with or without mention of antepartum condition), 654.02 (congenital abnormalities of uterus, delivered, with mention of postpartum complication), 654.03 (congenital abnormalities of uterus, antepartum condition or complication) and 1 more.

Notes that apply from higher levels

Instructions written at a parent level also apply to O34.01.

› From O34 Maternal care for abnormality of pelvic organs
Includes
  • the listed conditions as a reason for hospitalization or other obstetric care of the mother, or for cesarean delivery before onset of labor
Code first
  • any associated obstructed labor (O65.5)
Use additional code
  • code for specific condition

Broader instructions also apply from Chapter 15: Pregnancy, childbirth and the puerperium.

MS-DRG v44.0 grouping

All DRGs →

Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.

ICD-9-CM equivalent

Converter →
  • 654.01Congenital abnormalities of uterus, delivered, with or without mention of antepartum conditionapproximate
  • 654.02Congenital abnormalities of uterus, delivered, with mention of postpartum complicationapproximate
  • 654.03Congenital abnormalities of uterus, antepartum condition or complicationapproximate
  • 654.04Congenital abnormalities of uterus, postpartum condition or complicationapproximate

From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about O34.01

Is O34.01 billable?

Yes. O34.01 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can O34.01 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict O34.01 as a principal diagnosis.

Is O34.01 a CC or MCC?

No. O34.01 is neither a CC nor an MCC under MS-DRG v44.0.

What DRG does O34.01 group to?

O34.01 is used in the MS-DRG v44.0 logic for MS-DRG 817 (Other Antepartum Diagnoses with O.R. Procedures with MCC), MS-DRG 818 (Other Antepartum Diagnoses with O.R. Procedures with CC), MS-DRG 819 (Other Antepartum Diagnoses with O.R. Procedures without CC/MCC), MS-DRG 831 (Other Antepartum Diagnoses without O.R. Procedures with MCC), MS-DRG 832 (Other Antepartum Diagnoses without O.R. Procedures with CC) and MS-DRG 833 (Other Antepartum Diagnoses without O.R. Procedures without CC/MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.

What is the ICD-9 code for O34.01?

The CMS General Equivalence Mappings map O34.01 to ICD-9-CM 654.01, 654.02, 654.03 and 654.04.