ICD-10-CM Code For Unspecified Maternal Hypertension: Group Overview

The International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) code group O16 includes unspecified hypertensive disorders of pregnancy, childbirth, and the puerperium, covering elevated blood pressure states in pregnant or postpartum patients when a more specific diagnosis is not documented. These ICD-10-CM diagnosis codes are used to document clinical scenarios where hypertension is present but lacks sufficient detail to classify as gestational hypertension with or without proteinuria, preeclampsia, or chronic hypertension complicating pregnancy, capturing disease timing and clinical complexity relevant to maternal care. Accurate coding within the ICD-10-CM O16 group supports proper claim adjudication, complete clinical documentation, and appropriate reimbursement.

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ICD-10-CM O16: Unspecified Maternal Hypertension Overview

The ICD-10-CM O16 group represents unspecified hypertensive disorders occurring during pregnancy, childbirth, and the puerperium, targeting maternal cardiovascular and pregnancy-related conditions. These codes capture elevated blood pressure in pregnancy when insufficient detail is available to assign a more specific hypertensive disorder code. Accurate coding matters for appropriate reimbursement and for clear clinical and administrative records that support continuity of care.

When to Use

Use a code from this group when a patient during pregnancy, delivery, or the postpartum period has documented hypertension but the medical record does not specify severity, presence of proteinuria, or chronicity. These codes apply when clinicians document hypertension related to the pregnancy without additional qualifying details needed for a more specific hypertensive disorder code.

ICD-10-CM Codes

6 rows

ICD-10-CM Code	Description
O16.1	Unspecified maternal hypertension, first trimester
O16.2	Unspecified maternal hypertension, second trimester
O16.3	Unspecified maternal hypertension, third trimester
O16.4	Unspecified maternal hypertension, complicating childbirth
O16.5	Unspecified maternal hypertension, complicating the puerperium
O16.9	Unspecified maternal hypertension, unspecified trimester

DRG Codes

9 rows

DRG Code	Description
769	Postpartum and Post Abortion Diagnoses with O.R. Procedures
776	Postpartum and Post Abortion Diagnoses without O.R. Procedures
817	Other Antepartum Diagnoses with O.R. Procedures with MCC
818	Other Antepartum Diagnoses with O.R. Procedures with CC
819	Other Antepartum Diagnoses with O.R. Procedures without CC/MCC
831	Other Antepartum Diagnoses without O.R. Procedures with MCC
832	Other Antepartum Diagnoses without O.R. Procedures with CC
833	Other Antepartum Diagnoses without O.R. Procedures without CC/MCC
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Typical Clinical Scenarios

A pregnant woman in her third trimester presents for routine prenatal care with new-onset elevated blood pressures detected on multiple office visits but without proteinuria or other end-organ symptoms; she reports no headaches or visual changes and fetal testing is reassuring. Because hypertension is documented during pregnancy without features of preeclampsia, an unspecified maternal hypertension diagnosis from this group is assigned to capture the hypertensive disorder in pregnancy pending further characterization. Typical codes: O16.9
A multiparous patient presents to the emergency department with persistent mild to moderate hypertension identified on home blood pressure recordings during pregnancy, with intermittent edema but no laboratory evidence of renal dysfunction or significant proteinuria; urgent evaluation rules out severe features. This clinical circumstance—hypertension complicating pregnancy without specified severity or preeclampsia—warrants assignment of an unspecified maternal hypertension code to reflect the hypertensive condition requiring monitoring and management. Typical codes: O16.1, O16.9
A pregnant patient admitted for induction of labor has a history of gestational hypertension documented during prenatal care but incomplete outpatient records and no definitive documentation of whether proteinuria or severe features were present; the delivery episode requires a diagnosis to indicate hypertension in pregnancy as a comorbidity. In the absence of clear specification in the record, an unspecified maternal hypertension code from this group is used for the delivery hospitalization to reflect the documented hypertensive disorder. Typical codes: O16.2, O16.9

ICD-10-CM Code For Pre-existing Hypertension Complicating Pregnancy Childbirth And The Puerperium: Group Overview

O11-PRE-EXISTING-HYPERTENSION-WITH-PRE-ECLAMPSIA

ICD-10-CM Code For Pre Existing Hypertension With Pre Eclampsia: Group Overview

O12-GESTATIONAL-EDEMA-AND-PROTEINURIA

ICD-10-CM Code For Gestational Edema And Proteinuria Without Hypertension: Group Overview

O13-GESTATIONAL-HYPERTENSION-WITHOUT-PROTEINURIA

ICD-10-CM Code For Gestational Hypertension Without Significant Proteinuria: Group Overview

O14-PRE-ECLAMPSIA

ICD-10-CM Code For Pre Eclampsia: Group Overview

O15-ECLAMPSIA

ICD-10-CM Code For Eclampsia: Group Overview

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.

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When to Use

ICD-10-CM Codes

6 rows

ICD-10-CM Code	Description
O16.1	Unspecified maternal hypertension, first trimester
O16.2	Unspecified maternal hypertension, second trimester
O16.3	Unspecified maternal hypertension, third trimester
O16.4	Unspecified maternal hypertension, complicating childbirth
O16.5	Unspecified maternal hypertension, complicating the puerperium
O16.9	Unspecified maternal hypertension, unspecified trimester

DRG Codes

9 rows

DRG Code	Description
769	Postpartum and Post Abortion Diagnoses with O.R. Procedures
776	Postpartum and Post Abortion Diagnoses without O.R. Procedures
817	Other Antepartum Diagnoses with O.R. Procedures with MCC
818	Other Antepartum Diagnoses with O.R. Procedures with CC
819	Other Antepartum Diagnoses with O.R. Procedures without CC/MCC
831	Other Antepartum Diagnoses without O.R. Procedures with MCC
832	Other Antepartum Diagnoses without O.R. Procedures with CC
833	Other Antepartum Diagnoses without O.R. Procedures without CC/MCC
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Typical Clinical Scenarios

A pregnant woman in her third trimester presents for routine prenatal care with new-onset elevated blood pressures detected on multiple office visits but without proteinuria or other end-organ symptoms; she reports no headaches or visual changes and fetal testing is reassuring. Because hypertension is documented during pregnancy without features of preeclampsia, an unspecified maternal hypertension diagnosis from this group is assigned to capture the hypertensive disorder in pregnancy pending further characterization. Typical codes: O16.9
A multiparous patient presents to the emergency department with persistent mild to moderate hypertension identified on home blood pressure recordings during pregnancy, with intermittent edema but no laboratory evidence of renal dysfunction or significant proteinuria; urgent evaluation rules out severe features. This clinical circumstance—hypertension complicating pregnancy without specified severity or preeclampsia—warrants assignment of an unspecified maternal hypertension code to reflect the hypertensive condition requiring monitoring and management. Typical codes: O16.1, O16.9
A pregnant patient admitted for induction of labor has a history of gestational hypertension documented during prenatal care but incomplete outpatient records and no definitive documentation of whether proteinuria or severe features were present; the delivery episode requires a diagnosis to indicate hypertension in pregnancy as a comorbidity. In the absence of clear specification in the record, an unspecified maternal hypertension code from this group is used for the delivery hospitalization to reflect the documented hypertensive disorder. Typical codes: O16.2, O16.9

ICD-10-CM Code For Pre-existing Hypertension Complicating Pregnancy Childbirth And The Puerperium: Group Overview

O11-PRE-EXISTING-HYPERTENSION-WITH-PRE-ECLAMPSIA

ICD-10-CM Code For Pre Existing Hypertension With Pre Eclampsia: Group Overview

O12-GESTATIONAL-EDEMA-AND-PROTEINURIA

ICD-10-CM Code For Gestational Edema And Proteinuria Without Hypertension: Group Overview

O13-GESTATIONAL-HYPERTENSION-WITHOUT-PROTEINURIA

ICD-10-CM Code For Gestational Hypertension Without Significant Proteinuria: Group Overview

O14-PRE-ECLAMPSIA

ICD-10-CM Code For Pre Eclampsia: Group Overview

O15-ECLAMPSIA

ICD-10-CM Code For Eclampsia: Group Overview

Frequently Asked Questions

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Aug 11, 2026.Maintains the CPT code set's official descriptions and guidelines, licensed from the American Medical Association, used as the definitional source for CPT codes on this page.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's quarterly release of HCPCS Level II codes and short/long descriptors, the source for HCPCS code definitions and update history.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Aug 11, 2026.CMS's complete ICD-10-CM diagnosis code list, used to cross-reference diagnosis codes associated with this procedure or service.

Published by

Trek Health powers OpenPayer with a leading commercial payer intelligence platform, seamlessly converting fragmented payer data into actionable insights for provider organizations.

ICD-10-CM Code For Unspecified Maternal Hypertension: Group Overview

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ICD-10-CM O16: Unspecified Maternal Hypertension Overview

ICD-10-CM Code For Unspecified Maternal Hypertension: Group Overview

Sign up for ICD-10-CM Code For Unspecified Maternal Hypertension: Group Overview policy alerts

ICD-10-CM O16: Unspecified Maternal Hypertension Overview

When to Use

ICD-10-CM Codes

DRG Codes

Typical Clinical Scenarios

Related Codes

References

When to Use

ICD-10-CM Codes

DRG Codes

Typical Clinical Scenarios

Related Codes

References

ICD-10-CM Code For Unspecified Maternal Hypertension: Group Overview

Sign up for ICD-10-CM Code For Unspecified Maternal Hypertension: Group Overview policy alerts

ICD-10-CM O16: Unspecified Maternal Hypertension Overview

ICD-10-CM Code For Unspecified Maternal Hypertension: Group Overview

Sign up for ICD-10-CM Code For Unspecified Maternal Hypertension: Group Overview policy alerts

ICD-10-CM O16: Unspecified Maternal Hypertension Overview

When to Use

ICD-10-CM Codes

DRG Codes

Typical Clinical Scenarios

Related Codes

What does ICD-10-CM group `O16` represent?

Which specific codes are included in the `O16` group?

How does accurate use of `O16` codes affect reimbursement?

When should a coder choose an `O16` code instead of a more specific hypertensive pregnancy code?

What DRG groups are related to the `O16` diagnosis codes?

References

When to Use

ICD-10-CM Codes

DRG Codes

Typical Clinical Scenarios

Related Codes

What does ICD-10-CM group `O16` represent?

Which specific codes are included in the `O16` group?

How does accurate use of `O16` codes affect reimbursement?

When should a coder choose an `O16` code instead of a more specific hypertensive pregnancy code?

What DRG groups are related to the `O16` diagnosis codes?

References