2026 ICD-10-CM Diagnosis Code T38.4X6AUnderdosing of oral contraceptives, initial encounter
T38.4X6A is a billable ICD-10-CM diagnosis code for underdosing of oral contraceptives, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). The code is not accepted as a principal diagnosis by the Medicare Code Editor. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Underdosing of drugs and medicaments, initial encounter.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for T38.4X6A.
Coding GuidelinesGuidance
Underdosing refers to taking less of a medication than is prescribed by a provider or a manufacturer's instruction. Codes for underdosing should never be assigned as principal or first-listed codes. If a patient has a relapse or exacerbation of the medical condition for which the drug is prescribed because of the reduction in dose, then the medical condition itself should be coded.
The appropriate 7th character is to be added to each code from block Poisoning by, adverse effect of and underdosing of hormones and their synthetic substitutes and antagonists, not elsewhere classified (T38). Use the following options for the applicable episode of care:
- A - initial encounter
- D - subsequent encounter
- S - sequela
Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Levonorgestrel
a synthetic progestational hormone with actions similar to those of progesterone and about twice as potent as its racemic or (+-)-isomer (norgestrel). it is used for contraception, control of menstrual disorders, and treatment of endometriosis.Lynestrenol
a synthetic progestational hormone used often in mixtures with estrogens as an oral contraceptive (contraceptives, oral).Norethindrone
a synthetic progestational hormone with actions similar to those of progesterone but functioning as a more potent inhibitor of ovulation. it has weak estrogenic and androgenic properties. the hormone has been used in treating amenorrhea, functional uterine bleeding, endometriosis, and for contraception.Norethindrone Acetate
acetate ester of norethindrone that is used as a long-term contraceptive (contraceptive agents).Ethinyl Estradiol-Norgestrel Combination
ethinyl estradiol and norgestrel given in fixed proportions.Norgestrel
a synthetic progestational agent with actions similar to those of progesterone. this racemic or (+-)-form has about half the potency of the levo form (levonorgestrel). norgestrel is used as a contraceptive, ovulation inhibitor, and for the control of menstrual disorders and endometriosis.Norgestrienone
a synthetic steroid with progestational and contraceptive activities.
Table of Drugs and ChemicalsClinical
Substances in the Table of Drugs and Chemicals that reference this code family. Always confirm in the Tabular List before coding.
Patient EducationClinical
Birth Control
Birth control, also known as contraception, is the use of medicines, devices, or surgery to prevent pregnancy. There are many different types. Some are reversible, while others are permanent. Some types can also help prevent sexually transmitted infections (STIs).
The full article covers:
- What is birth control?
- What are the different types of birth control?
- What are some other forms of pregnancy prevention?
- What is emergency contraception?
- What else should I know about birth control?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert T38.4X6A to ICD-9-CMHistory
Code HistoryHistory
Questions About T38.4X6AOverview
Is T38.4X6A (Underdosing of oral contraceptives) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report underdosing of oral contraceptives, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T38.4X6A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for underdosing of oral contraceptives, such as an emergency visit or first evaluation.
Can T38.4X6A be a principal diagnosis?
No. The Medicare Code Editor rejects this code as a principal diagnosis because underdosing of oral contraceptives, initial encounter describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.
Footnotes
[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.
