Signs and Symptoms of Miscarriage
Vaginal bleeding is the earliest and most common sign of miscarriage, often accompanied by abdominal cramping or pelvic pain. 1, 2
Primary Clinical Manifestations
Vaginal Bleeding
- Bleeding or spotting represents the cardinal early warning sign of pregnancy loss, ranging from light spotting to heavy hemorrhage 1, 2
- Heavy bleeding is defined as saturating a sanitary pad with blood and clots more than once per hour, requiring immediate medical evaluation 1
- Bleeding may be pink, brown-tinged, or bright red with clots 3
Abdominal Pain and Cramping
- Cramping or abdominal pain typically accompanies bleeding in miscarriage 2, 4
- Pain may be localized to the lower abdomen or pelvis 5
- The combination of heavy bleeding with significant abdominal pain raises concern for complications requiring urgent assessment 5
Associated Symptoms Indicating Complications
Signs of Hemodynamic Compromise
- Lightheadedness or dizziness suggests significant blood loss and potential hemodynamic instability, warranting immediate evaluation 5
- Shoulder pain may indicate intra-abdominal hemorrhage from ruptured ectopic pregnancy 5
Infection-Related Symptoms
- Fever suggests endometritis or intraamniotic infection, which occurs in 13-38% of cases depending on management approach 6, 7
- Uterine tenderness on examination indicates possible infection 7
Ultrasound Findings Diagnostic of Miscarriage
Transvaginal ultrasound is the standard diagnostic test to confirm miscarriage, with specific criteria established to avoid misdiagnosis 6, 1, 8:
- Crown-rump length ≥7 mm with no cardiac activity 6
- Mean gestational sac diameter ≥25 mm with no embryo 6
- Absence of embryo with cardiac activity ≥14 days after visualization of gestational sac without yolk sac 6
Critical Diagnostic Considerations
Mandatory Workup Components
- Digital pelvic examination is absolutely contraindicated until ultrasound excludes ectopic pregnancy and placental causes of bleeding 3, 5
- Quantitative beta-hCG level is essential regardless of ultrasound findings to assess for ectopic pregnancy or retained tissue 3, 7
- Complete blood count assesses degree of blood loss and evaluates for infection 7, 5
Differential Diagnoses Requiring Exclusion
- Ectopic pregnancy accounts for 7-20% of pregnancies of unknown location and represents the most critical life-threatening diagnosis to exclude 3, 5
- Placental abruption can present with bleeding and pain in later pregnancy 3
- Cervical lesions, polyps, or cervicitis may cause bleeding without pregnancy loss 3
Epidemiology and Risk Context
- Miscarriage affects 15-20% of clinically recognized pregnancies, with approximately 80% occurring in the first 12 weeks of gestation 1, 2, 9
- An estimated 23 million miscarriages occur worldwide annually 9
- Risk factors include advanced maternal age (>35 years), paternal age >40 years, previous miscarriages, smoking, alcohol use, and extremes of body mass index 9
When to Seek Immediate Medical Attention
Patients should return immediately for worsening bleeding, severe abdominal pain, lightheadedness, shoulder pain, or fever 5: