In medical terminology, a miscarriage is classified as a “spontaneous abortion.” This does not mean it is the same as an induced abortion, which is a procedure to intentionally end a pregnancy. The two are fundamentally different events that share a clinical label, and that overlap in language causes real confusion for patients, especially when they see the word “abortion” on their medical records or hospital paperwork.
Why Doctors Use the Word “Abortion”
In medicine, “abortion” has historically referred to any pregnancy that ends before 20 weeks of gestation, regardless of the cause. A miscarriage is a “spontaneous abortion,” meaning the pregnancy ended on its own. An intentional procedure to end a pregnancy is an “induced abortion.” The National Institutes of Health draws this distinction clearly: a spontaneous abortion is the loss of a pregnancy before the 20th week, more commonly known as a miscarriage.
This terminology dates back long before abortion became a politically charged word. Doctors, nurses, and medical coders still use it in clinical documentation, diagnostic codes, and research literature. Your hospital discharge papers or insurance claims might list a diagnosis like “incomplete spontaneous abortion” or “missed abortion” when you experienced a miscarriage. Seeing that language can be jarring and even distressing, particularly for someone grieving a wanted pregnancy. There has been a push within the medical community to replace “abortion” with “pregnancy loss” or “miscarriage” in patient-facing communication, but the older terminology persists in medical records, billing systems, and coding manuals.
How Medical Records Code Miscarriage
The diagnostic coding system that hospitals and insurers use has an entire section dedicated to spontaneous abortion. These codes cover specific clinical scenarios: incomplete spontaneous abortion (where some pregnancy tissue remains), complete spontaneous abortion (where all tissue has passed), and missed abortion (where the pregnancy has stopped developing but hasn’t yet passed). Each code begins with “O03” for spontaneous abortion, which is categorically separate from codes used for induced procedures.
So while the word “abortion” may appear in your medical chart after a miscarriage, the codes distinguish it from an elective procedure. If you’re concerned about how a miscarriage is documented in your records, you can request a copy and ask your provider to clarify any terminology.
What Actually Causes a Miscarriage
Miscarriage is common. About 10 in 100 known pregnancies end in miscarriage, and for women over 40, roughly 1 in 3 pregnancies end this way. More than 80% of miscarriages happen before the 12th week of pregnancy.
The single biggest cause is chromosomal abnormalities in the embryo. Around 50% of first-trimester miscarriages are attributed to these genetic errors, where the embryo received too many or too few chromosomes during fertilization. These are random events, not caused by anything the pregnant person did or didn’t do. A Greek study examining 198 first-trimester miscarriage samples found abnormal chromosomes in about 42% of cases, with the vast majority being numerical errors (an extra or missing chromosome) rather than structural problems.
Other causes include hormonal imbalances, uterine abnormalities, infections, and certain chronic health conditions. But in many cases, no specific cause is ever identified.
The Medical Terms You Might Encounter
If you’ve had or are going through a miscarriage, you may hear several clinical terms that all fall under the umbrella of pregnancy loss:
- Threatened miscarriage (threatened abortion): Vaginal bleeding and cramping in a pregnancy that is still viable. The cervix remains closed and no tissue has passed. Many threatened miscarriages resolve, and the pregnancy continues.
- Missed miscarriage (missed abortion): The pregnancy has stopped developing, but the body hasn’t yet recognized the loss. There may be no bleeding or cramping, and it’s often discovered during a routine ultrasound.
- Incomplete miscarriage (incomplete abortion): Some pregnancy tissue has passed but some remains in the uterus. The cervix is open.
- Complete miscarriage: All pregnancy tissue has passed on its own without medical intervention.
In every one of these cases, “abortion” in the clinical name refers to spontaneous pregnancy loss, not a deliberate procedure.
Miscarriage and Abortion Use the Same Treatments
One reason the two get conflated is that managing a miscarriage sometimes requires the same medications or procedures used in induced abortion. When a pregnancy has stopped developing but the tissue hasn’t passed on its own, there are three options: waiting for the body to pass it naturally (expectant management), taking medication to help the process along, or having a minor surgical procedure to remove the tissue.
The medication regimen for both miscarriage management and induced abortion before 13 weeks is nearly identical. Both use the same two drugs in the same doses, administered the same way. The surgical option, a uterine aspiration procedure, is also the same for both. This overlap matters because in places where abortion is legally restricted, patients experiencing miscarriage sometimes face delays in receiving these standard treatments. Pharmacies may question prescriptions, and hospitals may hesitate over procedures, even when the pregnancy is clearly no longer viable.
For the patient, medical management of a miscarriage involves taking medication at home, then passing pregnancy tissue over the following hours or days. Success rates with medication range from about 80 to 85% within 7 to 10 days. The experience involves heavy bleeding, cramping, and the passage of tissue, and providers typically prescribe pain medication alongside the treatment.
Why the Distinction Matters
A miscarriage is an involuntary event. It happens without any decision or action by the pregnant person. An induced abortion is a medical procedure chosen by the patient. These are different experiences medically, emotionally, and legally, even though they share terminology and treatment methods.
The shared clinical language creates real problems. A study published in the BMJ noted that the word “abortion” is still widely used in medical literature to describe spontaneous pregnancy loss, and that medical professionals find it difficult to maintain one set of terms for patients and another for documentation. For someone reading their own medical chart after losing a wanted pregnancy, finding the word “abortion” can feel like a mischaracterization of what happened to them. If you encounter this term in your records and it concerns you, know that the clinical codes and context make the distinction clear to anyone reviewing your medical history.