ICD10BillableValid for clinical use
ICD-10 Code O99.511: Diseases of the respiratory system complicating pregnancy, first trimester
Reviewed by HealthAssure Clinical TeamUpdated 26 May 2026
What is this code?
ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Pregnancy, childbirth and the puerperium (O00-O9A).
đź“‹Clinical overview
This ICD-10 code is commonly used when documentation describes a maternal respiratory-system disease complicating pregnancy, childbirth, or the puerperium. The most accurate code depends on maternal timing and whether the chart more specifically identifies the underlying pulmonary or airway diagnosis elsewhere in the record.
When is it used?
- May be used when a clinician documents diseases of the respiratory system complicating pregnancy, first trimester in a patient's medical record.
- May appear in hospital records, claims, referrals, and clinical documentation.
- This code can be used as a clinically usable diagnosis entry in standardized coding workflows.
What it does not mean
- A code alone does not explain severity, treatment plan, or outcome.
- A medical code should not be treated as a substitute for a doctor's diagnosis or advice.
đź©şClinical context
When commonly used
- Obstetric, pulmonology, maternal-fetal medicine, inpatient, delivery, postpartum, and prenatal documentation where maternal respiratory disease materially affects pregnancy monitoring or management.
- Coding and utilization-review workflows where the record clearly ties maternal respiratory-system disease to pregnancy, childbirth, or the puerperium and maternal timing changes the final complication code.
Common workup
- Related procedures or service context already linked on this page include Obstetric ultrasound, Fetal nonstress testing.
Common management context
- Maternal respiratory-system disease follow-up often includes symptom review, oxygenation or pulmonary assessment context, medication review, obstetric monitoring, and coordination with pulmonology or maternal-fetal medicine.
- Documentation usually becomes more specific when the chart identifies trimester or delivery timing, the underlying pulmonary or airway diagnosis, severity, and whether additional maternal-fetal surveillance is needed.
- Specialist context already linked on this page includes Obstetrician, Gynecologist, Pulmonologist.
🔍Key distinctions
Important notes
- This ICD-10 family captures maternal respiratory-system disease as a pregnancy-related, childbirth-related, or puerperium-related complication, while separate diagnosis coding may still carry the underlying pulmonary disorder detail documented elsewhere in the chart.
- Trimester or maternal timing detail matters, and clearer chart language about the underlying respiratory condition can add specificity beyond this broad maternal complication family.
- This title reflects maternal respiratory-system disease complicating pregnancy, which is coded separately from similar maternal respiratory complications during childbirth or the puerperium.
- Trimester detail is part of the maternal respiratory-system disease code choice, so documentation that clearly states first, second, third, or unspecified trimester affects specificity.
Related codes to consider
O99.512Diseases of the respiratory system complicating pregnancy, second trimester
Related maternal respiratory-system disease ICD-10 code; documentation often becomes more specific when the chart identifies trimester or delivery timing, the underlying pulmonary diagnosis, or clearer pregnancy context.
O99.513Diseases of the respiratory system complicating pregnancy, third trimester
Related maternal respiratory-system disease ICD-10 code; documentation often becomes more specific when the chart identifies trimester or delivery timing, the underlying pulmonary diagnosis, or clearer pregnancy context.
O99.519Diseases of the respiratory system complicating pregnancy, unspecified trimester
Related maternal respiratory-system disease ICD-10 code; documentation often becomes more specific when the chart identifies trimester or delivery timing, the underlying pulmonary diagnosis, or clearer pregnancy context.
Code hierarchy
chapter
15Pregnancy, childbirth and the puerperium (O00-O9A)
block
O94-O9AOther obstetric conditions, not elsewhere classified
category
O99Other maternal diseases classifiable elsewhere but complicating pregnancy, childbirth and the puerperium
category
O99.5Diseases of the respiratory system complicating pregnancy, childbirth and the puerperium
category
O99.51Diseases of the respiratory system complicating pregnancy
currentO99.51
Where you may see this code
You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records.
Related specialists
ObstetricianGynecologistPulmonologist
Related procedures
Obstetric ultrasound
May appear in pregnancy follow-up pathways when maternal diseases complicate pregnancy and fetal well-being is monitored.
Fetal nonstress testing
May be used in selected higher-risk pregnancy monitoring pathways.
Related codes
Sibling codes
Coverage-related procedures and services
Coding guidelines
Common synonyms
Diseases of the respiratory system complicating pregnancy, first trimester
Frequently asked questions
About this content
This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.