a. General Rules for Obstetric Cases
1) Codes from chapter 15 and sequencing priority
Obstetric cases require codes from chapter 15, codes in the range O00-O9A, Pregnancy, Childbirth, and the Puerperium. Chapter 15 codes have sequencing priority over codes from other chapters. Additional codes from other chapters may be used in conjunction with chapter 15 codes to further specify conditions. Should the provider document that the pregnancy is incidental to the encounter, then code Z33.1, Pregnant state, incidental, should be used in place of any chapter 15 codes. It is the provider's responsibility to state that the condition being treated is not affecting the pregnancy.
2) Chapter 15 codes used only on the maternal record
Chapter 15 codes are to be used only on the maternal record, never on the record of the newborn.
3) Final character for trimester
The majority of codes in Chapter 15 have a final character indicating the trimester of pregnancy. The timeframes for the trimesters are indicated at the beginning of the chapter. If trimester is not a component of a code, it is because the condition always occurs in a specific trimester, or the concept of trimester of pregnancy is not applicable. Certain codes have characters for only certain trimesters because the condition does not occur in all trimesters, but it may occur in more than just one.
Assignment of the final character for trimester should be based on the provider's documentation of the trimester (or number of weeks) for the current admission/encounter. This applies to the assignment of trimester for pre-existing conditions as well as those that develop during or are due to the pregnancy. The provider's documentation of the number of weeks may be used to assign the appropriate code identifying the trimester.
Whenever delivery occurs during the current admission, and there is an "in childbirth" option for the obstetric complication being coded, the "in childbirth" code should be assigned.
4) Selection of trimester for inpatient admissions that encompass more than one trimester
In instances when a patient is admitted to a hospital for complications of pregnancy during one trimester and remains in the hospital into a subsequent trimester, the trimester character for the antepartum complication code should be assigned on the basis of the trimester when the complication developed, not the trimester of the discharge. If the condition developed prior to the current admission/encounter or represents a pre-existing condition, the trimester character for the trimester at the time of the admission/encounter should be assigned.
5) Unspecified trimester
Each category that includes codes for trimester has a code for "unspecified trimester." The "unspecified trimester" code should rarely be used, such as when the documentation in the record is insufficient to determine the trimester and it is not possible to obtain clarification.
6) 7th character for Fetus Identification
Where applicable, a 7th character is to be assigned for certain categories (O31, O32, O33.3 - O33.6, O35, O36, O40, O41, O60.1, O60.2, O64, and O69) to identify the fetus for which the complication code applies.
Assign 7th character "0":
- For single gestations
- When the documentation in the record is insufficient to determine the fetus affected and it is not possible to obtain clarification.
- When it is not possible to clinically determine which fetus is affected.
b. Selection of OB Principal or First-listed Diagnosis
1) Routine outpatient prenatal visits
For routine outpatient prenatal visits when no complications are present, a code from category Z34, Encounter for supervision of normal pregnancy, should be used as the first-listed diagnosis. These codes should not be used in conjunction with chapter 15 codes.
2) Supervision of High-Risk Pregnancy
Codes from category O09, Supervision of high-risk pregnancy, are intended for use only during the prenatal period. For complications during the labor or delivery episode as a result of a high-risk pregnancy, assign the applicable complication codes from Chapter 15. If there are no complications during the labor or delivery episode, assign code O80, Encounter for full-term uncomplicated delivery.
For routine prenatal outpatient visits for patients with high-risk pregnancies, a code from category O09, Supervision of high-risk pregnancy, should be used as the first-listed diagnosis. Secondary chapter 15 codes may be used in conjunction with these codes if appropriate.
3) Episodes when no delivery occurs
In episodes when no delivery occurs, the principal diagnosis should correspond to the principal complication of the pregnancy which necessitated the encounter. Should more than one complication exist, all of which are treated or monitored, any of the complications codes may be sequenced first.
4) When a delivery occurs
When an obstetric patient is admitted and delivers during that admission, the condition that prompted the admission should be sequenced as the principal diagnosis. If multiple conditions prompted the admission, sequence the one most related to the delivery as the principal diagnosis. A code for any complication of the delivery should be assigned as an additional diagnosis. In cases of cesarean delivery, if the patient was admitted with a condition that resulted in the performance of a cesarean procedure, that condition should be selected as the principal diagnosis. If the reason for the admission was unrelated to the condition resulting in the cesarean delivery, the condition related to the reason for the admission should be selected as the principal diagnosis.
5) Outcome of delivery
A code from category Z37, Outcome of delivery, should be included on every maternal record when a delivery has occurred. These codes are not to be used on subsequent records or on the newborn record.
c. Pre-existing conditions versus conditions due to the pregnancy
Certain categories in Chapter 15 distinguish between conditions of the mother that existed prior to pregnancy (pre-existing) and those that are a direct result of pregnancy. When assigning codes from Chapter 15, it is important to assess if a condition was pre-existing prior to pregnancy or developed during or due to the pregnancy in order to assign the correct code.
Categories that do not distinguish between pre-existing and pregnancy-related conditions may be used for either. It is acceptable to use codes specifically for the puerperium with codes complicating pregnancy and childbirth if a condition arises postpartum during the delivery encounter.
d. Pre-existing hypertension in pregnancy
Category O10, Pre-existing hypertension complicating pregnancy, childbirth and the puerperium, includes codes for hypertensive heart and hypertensive chronic kidney disease. When assigning one of the O10 codes that includes hypertensive heart disease or hypertensive chronic kidney disease, it is necessary to add a secondary code from the appropriate hypertension category to specify the type of heart failure or chronic kidney disease.
See Section I.C.9. Hypertension.
e. Fetal Conditions Affecting the Management of the Mother
1) Codes from categories O35 and O36
Codes from categories O35, Maternal care for known or suspected fetal abnormality and damage, and O36, Maternal care for other fetal problems, are assigned only when the fetal condition is actually responsible for modifying the management of the mother, i.e., by requiring diagnostic studies, additional observation, special care, or termination of pregnancy. The fact that the fetal condition exists does not justify assigning a code from this series to the mother's record.
2) In utero surgery
In cases when surgery is performed on the fetus, a diagnosis code from category O35, Maternal care for known or suspected fetal abnormality and damage, should be assigned identifying the fetal condition. Assign the appropriate procedure code for the procedure performed.
No code from Chapter 16, the perinatal codes, should be used on the mother's record to identify fetal conditions. Surgery performed in utero on a fetus is still to be coded as an obstetric encounter.
f. HIV Infection in Pregnancy, Childbirth and the Puerperium
During pregnancy, childbirth or the puerperium, a patient admitted because of an HIV-related illness should receive a principal diagnosis from subcategory O98.7-, Human immunodeficiency [HIV] disease complicating pregnancy, childbirth and the puerperium, followed by the code(s) for the HIV-related illness(es).
Patients with asymptomatic HIV infection status admitted during pregnancy, childbirth, or the puerperium should receive codes of O98.7- and Z21, Asymptomatic human immunodeficiency virus [HIV] infection status.
g. Diabetes mellitus in pregnancy
Diabetes mellitus is a significant complicating factor in pregnancy. Pregnant women who are diabetic should be assigned a code from category O24, Diabetes mellitus in pregnancy, childbirth, and the puerperium, first, followed by the appropriate diabetes code(s) (E08-E13) from Chapter 4.
h. Long term use of insulin and oral hypoglycemics
Code Z79.4, Long-term (current) use of insulin, or code Z79.84, Long-term (current) use of oral hypoglycemic drugs, should also be assigned if the diabetes mellitus is being treated with insulin or oral medications. If the patient is treated with both oral medications and insulin, only the code for insulin-controlled should be assigned.
i. Gestational (pregnancy induced) diabetes
Gestational (pregnancy induced) diabetes can occur during the second and third trimester of pregnancy in women who were not diabetic prior to pregnancy. Gestational diabetes can cause complications in the pregnancy similar to those of pre-existing diabetes mellitus. It also puts the woman at greater risk of developing diabetes after the pregnancy. Codes for gestational diabetes are in subcategory O24.4, Gestational diabetes mellitus. No other code from category O24, Diabetes mellitus in pregnancy, childbirth, and the puerperium, should be used with a code from O24.4.
The codes under subcategory O24.4 include diet controlled, insulin controlled, and controlled by oral hypoglycemic drugs. If a patient with gestational diabetes is treated with both diet and insulin, only the code for insulin-controlled is required. If a patient with gestational diabetes is treated with both diet and oral hypoglycemic medications, only the code for "controlled by oral hypoglycemic drugs" is required. Code Z79.4, Long-term (current) use of insulin or code Z79.84, Long-term (current) use of oral hypoglycemic drugs, should not be assigned with codes from subcategory O24.4.
An abnormal glucose tolerance in pregnancy is assigned a code from subcategory O99.81, Abnormal glucose complicating pregnancy, childbirth, and the puerperium.
j. Sepsis and septic shock complicating abortion, pregnancy, childbirth and the puerperium
When assigning a chapter 15 code for sepsis complicating abortion, pregnancy, childbirth, and the puerperium, a code for the specific type of infection should be assigned as an additional diagnosis. If severe sepsis is present, a code from subcategory R65.2, Severe sepsis, and code(s) for associated organ dysfunction(s) should also be assigned as additional diagnoses.
k. Puerperal sepsis
Code O85, Puerperal sepsis, should be assigned with a secondary code to identify the causal organism (e.g., for a bacterial infection, assign a code from category B95-B96, Bacterial infections in conditions classified elsewhere). A code from category A40, Streptococcal sepsis, or A41, Other sepsis, should not be used for puerperal sepsis. If applicable, use additional codes to identify severe sepsis (R65.2-) and any associated acute organ dysfunction.
l. Alcohol and tobacco use during pregnancy, childbirth and the puerperium
1) Alcohol use during pregnancy, childbirth and the puerperium
Codes under subcategory O99.31, Alcohol use complicating pregnancy, childbirth, and the puerperium, should be assigned for any pregnancy case when a mother uses alcohol during the pregnancy or postpartum. A secondary code from category F10, Alcohol related disorders, should also be assigned to identify manifestations of the alcohol use.
2) Tobacco use during pregnancy, childbirth and the puerperium
Codes under subcategory O99.33, Smoking (tobacco) complicating pregnancy, childbirth, and the puerperium, should be assigned for any pregnancy case when a mother uses any type of tobacco product during the pregnancy or postpartum. A secondary code from category F17, Nicotine dependence, should also be assigned to identify the type of nicotine dependence.
m. Poisoning, toxic effects, adverse effects and underdosing in a pregnant patient
A code from subcategory O9A.2, Injury, poisoning and certain other consequences of external causes complicating pregnancy, childbirth, and the puerperium, should be sequenced first, followed by the appropriate injury, poisoning, toxic effect, adverse effect or underdosing code, and then the additional code(s) that specifies the condition caused by the poisoning, toxic effect, adverse effect or underdosing. See Section I.C.19. Adverse effects, poisoning, underdosing and toxic effects.
n. Normal Delivery, Code O80
1) Encounter for full term uncomplicated delivery
Code O80 should be assigned when a woman is admitted for a full-term normal delivery and delivers a single, healthy infant without any complications antepartum, during the delivery, or postpartum during the delivery episode. Code O80 is always a principal diagnosis. It is not to be used if any other code from chapter 15 is needed to describe a current complication of the antenatal, delivery, or perinatal period. Additional codes from other chapters may be used with code O80 if they are not related to or are in any way complicating the pregnancy.
2) Uncomplicated delivery with resolved antepartum complication
Code O80 may be used if the patient had a complication at some point during the pregnancy, but the complication is not present at the time of the admission for delivery.
3) Outcome of delivery for O80
Z37.0, Single live birth, is the only outcome of delivery code appropriate for use with O80.
o. The Peripartum and Postpartum Periods
1) Peripartum and Postpartum periods
The postpartum period begins immediately after delivery and continues for six weeks following delivery. The peripartum period is defined as the last month of pregnancy to five months postpartum.
2) Peripartum and postpartum complication
A postpartum complication is any complication occurring within the six-week period.
3) Pregnancy-related complications after 6 week period
Chapter 15 codes may also be used to describe pregnancy-related complications after the peripartum or postpartum period if the provider documents that a condition is pregnancy related.
4) Admission for routine postpartum care following delivery outside hospital
When the mother delivers outside the hospital prior to admission and is admitted for routine postpartum care and no complications are noted, code Z39.0, Encounter for care and examination of mother immediately after delivery, should be assigned as the principal diagnosis.
5) Pregnancy associated cardiomyopathy
Pregnancy associated cardiomyopathy, code O90.3, is unique in that it may be diagnosed in the third trimester of pregnancy but may continue to progress months after delivery. For this reason, it is referred to as peripartum cardiomyopathy. Code O90.3 is only for use when the cardiomyopathy develops as a result of pregnancy in a woman who did not have pre-existing heart disease.
p. Code O94, Sequelae of complication of pregnancy, childbirth, and the puerperium
1) Code O94
Code O94, Sequelae of complication of pregnancy, childbirth, and the puerperium, is for use in those cases when an initial complication of a pregnancy develops a sequelae requiring care or treatment at a future date.
2) After the initial postpartum period
This code may be used at any time after the initial postpartum period.
3) Sequencing of Code O94
This code, like all sequela codes, is to be sequenced following the code describing the sequelae of the complication.
q. Termination of Pregnancy and Spontaneous abortions
1) Abortion with Liveborn Fetus
2) Retained Products of Conception following an abortion
Subsequent encounters for retained products of conception following a spontaneous abortion or elective termination of pregnancy are assigned the appropriate code from category O03, Spontaneous abortion, or codes O07.4, Failed attempted termination of pregnancy without complication and Z33.2, Encounter for elective termination of pregnancy. This advice is appropriate even when the patient was discharged previously with a discharge diagnosis of complete abortion.
3) Complications leading to abortion
r. Abuse in a pregnant patient
For suspected or confirmed cases of abuse of a pregnant patient, a code(s) from subcategories O9A.3, Physical abuse complicating pregnancy, childbirth, and the puerperium, O9A.4, Sexual abuse complicating pregnancy, childbirth, and the puerperium, and O9A.5, Psychological abuse complicating pregnancy, childbirth, and the puerperium, should be sequenced first, followed by the appropriate codes (if applicable) to identify any associated current injury due to physical abuse, sexual abuse, and the perpetrator of abuse.
See Section I.C.19. Adult and child abuse, neglect and other maltreatment.
s. COVID-19 infection in pregnancy, childbirth, and the puerperium
During pregnancy, childbirth or the puerperium, when COVID-19 is the reason for admission/encounter , code O98.5-, Other viral diseases complicating pregnancy, childbirth and the puerperium, should be sequenced as the principal/first-listed diagnosis, and code U07.1, COVID-19, and the appropriate codes for associated manifestation(s) should be assigned as additional diagnoses. Codes from Chapter 15 always take sequencing priority.
If the reason for admission/encounter is unrelated to COVID-19 but the patient tests positive for COVID-19 during the admission/encounter, the appropriate code for the reason for admission/encounter should be sequenced as the principal/first-listed diagnosis, and codes O98.5- and U07.1, as well as the appropriate codes for associated COVID-19 manifestations, should be assigned as additional diagnoses.