A spontaneous abortion occurs in early pregnancy when the uterus evacuates the products of conception. A complete spontaneous abortion is when the uterus expels all of the pregnancy tissue. If there is vaginal bleeding but tissue remains in the uterus and the cervical os is dilated, this is considered an incomplete abortion. A missed abortion is defined as a pregnancy loss with a closed cervical os.
Approximately 10% of clinically recognized pregnancies end in a miscarriage, and 80% of these occur within the first trimester. It is estimated that about 50% of these losses are due to fetal chromosomal abnormalities.
Vaginal bleeding and uterine cramping are the main symptoms of pregnancy loss.
Risk factors for early pregnancy loss included advanced maternal age, history of prior pregnancy loss, endocrine abnormalities (eg, diabetes, thyroid disease), short intervals between pregnancies, infections, autoimmune diseases, and uterine anomalies.
Related topic: stillbirth
Spontaneous abortion
Alerts and Notices
Synopsis
Codes
ICD10CM:
003.9 – Complete or unspecified spontaneous abortion without complication
SNOMEDCT:
17369002 – Miscarriage
003.9 – Complete or unspecified spontaneous abortion without complication
SNOMEDCT:
17369002 – Miscarriage
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Diagnostic Pearls
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Differential Diagnosis & Pitfalls
- Ectopic pregnancy – Pregnancy located outside of the uterus.
- Early viable intrauterine pregnancy – Viable pregnancy seen on ultrasound, or criteria has not been made for early pregnancy loss and it is too early in the pregnancy to see a yolk sac.
- Incomplete abortion – Retained products of conception after some initial vaginal bleeding.
- Missed abortion – Pregnancy tissue in uterus but criteria have been met for early pregnancy loss, or patient previously had viable intrauterine pregnancy and now has no cardiac activity.
- Threatened abortion – Vaginal bleeding in early pregnancy, closed cervical os, and diagnostic criteria for pregnancy loss has not been made.
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Therapy
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Drug Reaction Data
Below is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.
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References
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Last Reviewed:08/17/2020
Last Updated:04/30/2023
Last Updated:04/30/2023