Reproductive · Spontaneous Abortion
The facts most likely to be tested
Inevitable abortion is characterized by vaginal bleeding and cramping in the presence of a dilated cervical os.
The products of conception remain intrauterine in an inevitable abortion, distinguishing it from an incomplete or complete abortion.
Transvaginal ultrasound is the diagnostic gold standard to confirm the presence of an intrauterine pregnancy and assess for fetal cardiac activity.
The cervical os is physically open on bimanual examination, which is the pathognomonic physical exam finding.
Management for a hemodynamically stable patient includes expectant management, medical management with misoprostol, or surgical evacuation via suction curettage.
Surgical evacuation is the mandatory treatment choice if the patient presents with hemodynamic instability, sepsis, or severe hemorrhage.
Rh(D) immunoglobulin must be administered to all Rh-negative patients to prevent alloimmunization.
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A 26-year-old G2P1 woman at 10 weeks gestation presents to the emergency department with moderate vaginal bleeding and rhythmic lower abdominal pain. On physical examination, her vital signs are stable. A speculum exam reveals a dilated cervical os with visible tissue at the external os. A transvaginal ultrasound confirms an intrauterine pregnancy with no fetal cardiac activity.
What is the most appropriate next step in management?
Surgical evacuation (suction curettage)
The presence of a dilated cervical os with products of conception confirms an inevitable abortion; given the presence of tissue at the os, surgical evacuation is the definitive management to prevent hemorrhage and infection.
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Etiology / Epidemiology
Occurs in first trimester pregnancies; primary risk factors include advanced maternal age and chromosomal abnormalities.
Clinical Manifestations
Presents with vaginal bleeding and cramping with a dilated cervical os; the hallmark is the inability to stop the process.
Diagnosis
Diagnosis is clinical via pelvic exam showing a dilated cervical os; transvaginal ultrasound confirms the presence of an intrauterine pregnancy.
Treatment
Management involves expectant management, misoprostol, or surgical evacuation (D&C); do not use if signs of infection.
Prognosis
Most patients recover fully; hemorrhage and infection are the primary risks requiring immediate intervention.
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Epidemiology & Etiology
Inevitable abortion is a subset of spontaneous abortion occurring before 20 weeks gestation. It is most frequently caused by fetal aneuploidy. Advanced maternal age and prior history of pregnancy loss are significant clinical predictors.
Pertinent Anatomy
The cervical os is the critical anatomical landmark. In an inevitable abortion, the internal os is dilated, allowing for the passage of products of conception.
Pathophysiology
The process begins with uterine contractions and cervical dilation. Once the cervical os is open, the pregnancy cannot be salvaged. The separation of the placenta from the uterine wall leads to vaginal bleeding and eventual expulsion of the fetus.
Clinical Manifestations
Patients present with heavy vaginal bleeding and rhythmic lower abdominal pain. The pathognomonic finding is a dilated cervical os on physical exam. Red flags include fever, foul-smelling discharge, or hemodynamic instability, which suggest septic abortion.
Diagnosis
The gold standard for diagnosis is a physical exam demonstrating a dilated cervical os. Transvaginal ultrasound is used to assess the status of the pregnancy and rule out ectopic gestation. A serial beta-hCG may be used to confirm non-viability if the ultrasound is inconclusive.
Treatment
For stable patients, misoprostol is the first-line medical management to facilitate uterine evacuation. Surgical management via dilation and curettage (D&C) is indicated for heavy bleeding or patient preference. Contraindications for medical management include hemodynamic instability or suspected infection.
Prognosis
Most patients have an uncomplicated recovery. Key complications include hemorrhage and endometritis. Patients should be monitored for excessive bleeding and instructed to return if they develop a fever.
Differential Diagnosis
Threatened abortion: cervical os is closed
Incomplete abortion: some products of conception remain in the uterus
Complete abortion: all products of conception expelled, os closes
Ectopic pregnancy: positive pregnancy test with empty uterus on ultrasound
Cervical insufficiency: painless cervical dilation in the second trimester