The Medicine and ICD-10 Coding of Abortion

Medical terminology of a fetus not carried to full term.

Today I am going to talk about what seems to be a very politically charged topic at the moment, but I am not actually going there. I want to review the term “abortion,” in medical terminology, and discuss procedures relating to a fetus not carried to full term.

People generally do not read the textbook. Although ovulation is usually asserted to occur around 14 days prior to onset of menses, with a fertility period of approximately six days preceding and including the day of ovulation, in reality, the time during which a woman can conceive is rather variable, and often unpredictable. Adolescent and perimenopausal individuals, and women with irregular menses, have even less reliable timing.

Fertilization of the egg by the sperm occurs in the fallopian tube during that fertile period, and under normal circumstances, the fertilized egg travels down until it reaches the uterus, and the 70 to 100 cell blastocyst then implants against the uterine wall. There are differing opinions as to whether conception is considered the moment of fertilization or implantation. However, unless implantation occurs (in a normal uterine location), there is no chance of a pregnancy that will result in delivery of a baby. The fertilized yet-not-implanted egg gets expelled during menstruation.

The word “embryo” refers to the period from time of implantation to the end of the eighth week after conception. From the beginning of the ninth week on, it is called a “fetus.” At the moment of delivery, the term is “neonate,” newborn infant, or baby. Fetuses are not viable prior to 22 weeks of gestation, and likelihood of survival increases to between 60 and 70 percent at 24 weeks gestation. About 40 percent of premature infants at this age will suffer long-term health complications.

An ectopic pregnancy is when a fertilized egg grows outside of the main cavity of the uterus. More than 90 percent of these occur in a fallopian tube at high risk for rupture. Other locations include ovarian, in an abnormal area in the uterus (like cornual, cervical, or in a cesarean scar), or abdominal. Ectopic pregnancies can be further complicated by occurring in concert with an intrauterine pregnancy, often because they are more common in cases of infertility treatment. “Uncomplicated” ectopic pregnancy ICD-10-CM codes are found in O00.-, and codes for ectopic and molar pregnancies with complications are housed in O08.-.

Fetal survival of an ectopic pregnancy is exceedingly rare, and there is a grave threat to the mother’s life if it is not terminated in a timely fashion. The only treatment for an ectopic pregnancy is ending the pregnancy, and it often requires surgical intervention, which results in excision/resection of the affected  body part.

The medical definition of abortion is “the termination of a pregnancy after, accompanied by, resulting in, or closely followed by the death of the embryo or fetus.” Secondary definitions are “spontaneous expulsion of a human fetus during the first 12 weeks of gestation” and “induced expulsion of a human fetus.”

In other words, a miscarriage, in medical terms, is called a spontaneous abortion. The most common causes of miscarriage are genetic or chromosomal abnormalities, placental issues, medical or anatomical conditions involving the mother, and infection. Spontaneous abortions most commonly occur so early in the pregnancy (weeks 0-6) that the patient may not even be aware they are pregnant, and may think it is just a late period. An estimated 10-15 percent of known pregnancies end in miscarriage.

If the embryo or fetus dies and the body naturally expels all the products of conception, it is termed “complete abortion.” If some of the products pass, but some parts of the fetus, placenta, or membranes are retained, it is called an “incomplete abortion.” An “inevitable abortion” is the scenario when the cervix has dilated in preparation for expulsion, but has not yet done so. For some coding reason unfathomable to me as a clinician, inevitable abortion indexes to O03.4, Incomplete spontaneous abortion without complication.

A “missed abortion” (O02.1) is when a fetus has died (not proximately, usually days to weeks ago), but the body does not proceed to expel the nonviable intrauterine pregnancy. A “septic abortion” is a result of intrauterine infection following an abortion. Finally, a “threatened abortion” (O20.0) is vaginal bleeding in pregnancy before 20 weeks with a closed cervix (i.e., not an inevitable abortion). A total of 25 percent of pregnancies have some bleeding in early pregnancy, and approximately half of these progress to abortion.

There are other complications of pregnancy that can result in the need for removal of nonviable products of conception. These include a blighted ovum (O02.0), in which an early embryo never develops or arrests, and a hydatidiform mole (AKA molar pregnancy, O01.-), when a noncancerous tumor forms instead of a healthy placenta. Complete and incomplete spontaneous abortions and their complications, such as pelvic infection, hemorrhage, sepsis, and shock, are coded in O03.-.

These spontaneous pregnancy losses are distinct from elective termination of pregnancy. In ICD-10-CM, there is a distinction between an encounter for elective termination of pregnancy without complications (Z33.2) and conditions/complications following induced (O04.-) or failed attempted termination (O07.-) of pregnancy.

Inducing abortion can either be accomplished by procedural or medical means. For outpatient procedures, Current Procedural Terminology (CPT) codes are utilized. The American College of Obstetrics and Gynecology (ACOG) recommends that abortions after 20 weeks be reported using a delivery code. However, they stipulate that some state legislatures legally define the distinction between a miscarriage and a stillbirth by the number of weeks or by weight, and this may guide the choice of CPT code.

If a patient is admitted in the hospital, then ICD-10-PCS codes are used. The body part for the obstetrics section is always some version of products of conception (POC, retained products, or ectopic).

• If products of conception are manually delivered without instrumentation, whether a liveborn, full-term fetus or nonviable products of conception, like a stillborn, the code is 10E0XZZ, Delivery of Products of Conception, External approach.
• If assistance is needed, like forceps or vacuum extraction, the root operation is D-Extraction.
• Extraction is also the correct root operation for retained or ectopic products of conception via natural/artificial opening, with or without endoscopic assistance.
• However, I found it interesting that if there is an ectopic pregnancy requiring operative intervention, like a salpingectomy, the PCS code is still found in the Obstetrics section. The root operation is resection, and the body part is products of conception, ectopic. Treatment of an ectopic pregnancy is not considered, nor is it coded in the section of Abortion.
• If the intent and what is accomplished is an elective termination of pregnancy, i.e., an abortion, the root operation is A-Abortion. I imagine the most commonly used approach is via natural or artificial opening (with or without endoscope), and the last character denotes whether vacuum extraction, laminaria, abortifacient, or simple curettage (no qualifier) was used.
• D&C stands for Dilation and curettage, in which the lining of the uterus is scraped with a sharp instrument. This may be used after miscarriage (root operation of extraction) or for elective abortions (root operation of abortion) to clear the uterine lining.
• D&E signifies Dilation and evacuation. It usually uses a combination of vacuum aspiration and the use of surgical tools. Again, which root operation this procedure falls under in ICD-10-PCS depends on what the intent was (e.g., treatment of spontaneous abortion of nonviable products of conception or elective abortion).

I hope this sheds light on the definitions, ICD-10-CM diagnoses, and procedure coding of miscarriage and abortion. It’s the best I can do.

Resources:

• Ferguson S, 10 Things to Know About Fertilization, Healthline, December 3, 2018.
• Griebel CP, Halvorsen J, Golemon TB, Day AA. Management of spontaneous abortion. Am Fam Physician. 2005 Oct 1;72(7):1243-50. PMID: 16225027.
• Billing for Interruption of Pregnancy: Early Pregnancy Loss | ACOG
• Gray L, ICD-10-PCS Obstetrics Coding, ICD10monitor, October 1, 2012.
• Wells K, 1931 State Law Make Abortion a Felony if Roe Falls, Warns Michigan Attorney General, Medscape, May 11, 2022.