What is the management for a pregnant patient presenting with lower abdominal pain, mild vaginal bleeding, and a palpable uterus at the umbilicus, with fetal heart tones present and no signs of severe complications?

Management of Threatened Abortion in Second Trimester

This patient has a threatened abortion with reassuring features and should be managed expectantly with close outpatient follow-up, Rh status assessment for potential anti-D immunoglobulin administration, and clear instructions for warning signs requiring immediate return. 1

Immediate Assessment and Risk Stratification

The clinical presentation indicates a threatened abortion rather than a pregnancy emergency requiring immediate intervention. Key reassuring features include:

• Hemodynamic stability with normal vital signs and no signs of hemorrhagic shock 1
• Closed cervix on examination, indicating the pregnancy has not progressed to inevitable abortion 2
• Viable fetus confirmed by fetal heart tones at 150 bpm, which is within normal range 1, 3
• Appropriate uterine size for gestational age (palpable at umbilicus suggests approximately 20 weeks) 1
• Absence of peritoneal signs (no rebound or guarding), making ruptured ectopic pregnancy or other surgical emergencies unlikely 3

The mild suprapubic tenderness and vaginal bleeding are consistent with threatened abortion, which occurs in approximately 20-30% of early pregnancies and has variable outcomes 2, 4.

Essential Diagnostic Evaluation

Ultrasound Assessment

Perform transvaginal ultrasound immediately to confirm intrauterine pregnancy location, assess fetal viability with cardiac activity visualization, evaluate placental location and position (to exclude placenta previa before any digital examination), measure amniotic fluid volume, and assess for any signs of abruption or subchorionic hemorrhage 1, 4. The ultrasound is critical even with reassuring fetal heart tones, as clinical assessment alone has only 38.8% concordance with definitive diagnosis 2.

Laboratory Testing

Obtain the following baseline studies:

• Rh status determination immediately, as anti-D immunoglobulin administration may be indicated 5, 1
• Complete blood count to assess for anemia from bleeding 5
• Type and screen in case transfusion becomes necessary 5
• Quantitative β-hCG for baseline documentation, though less critical at this gestational age with confirmed fetal heart tones 1, 6

Rh Immunoglobulin Administration

If the patient is Rh-negative, administer 50 μg of anti-D immunoglobulin for first-trimester threatened abortion or 300 μg if beyond 12 weeks gestation. 5 While ACOG notes that evidence for prophylaxis in threatened abortion with a viable fetus before 12 weeks is limited, many physicians administer it when there is "heavy" bleeding or associated abdominal pain, or when the event occurs near 12 weeks' gestation 5. Given this patient has both bleeding and abdominal pain at approximately 20 weeks (based on uterine size), anti-D immunoglobulin administration is strongly recommended 5.

Expectant Management Protocol

Patient Education and Warning Signs

Provide detailed instructions about signs and symptoms requiring immediate return to the emergency department:

• Increased vaginal bleeding (soaking more than one pad per hour for two consecutive hours) 5
• Severe or worsening abdominal pain that is not relieved by acetaminophen 5
• Fever (temperature >38°C/100.4°F), which may indicate infection 5
• Dizziness, lightheadedness, or syncope, suggesting hemorrhage 1
• Passage of tissue or clots 2
• Decreased or absent fetal movement (if patient has been feeling movement) 5
• Gush of fluid, suggesting rupture of membranes 5

Follow-Up Arrangements

Schedule follow-up within 24-48 hours with obstetrics for repeat assessment 1. This should include:

• Repeat ultrasound to confirm continued fetal viability 1, 4
• Assessment of bleeding pattern (increasing, decreasing, or stable) 2
• Evaluation for any signs of infection (fever, malodorous discharge, leukocytosis) 5
• Counseling about prognosis and activity restrictions 1

Activity and Lifestyle Modifications

While evidence for bed rest is limited, counsel the patient to:

• Avoid strenuous activity and heavy lifting until bleeding resolves 1
• Abstain from sexual intercourse until cleared by obstetrics 1
• Avoid tampons and use pads only to monitor bleeding 1
• Maintain adequate hydration 5

Critical Pitfalls to Avoid

Never perform digital bimanual examination before ultrasound excludes placenta previa in patients beyond first trimester, as this can precipitate catastrophic hemorrhage 1. In this case, speculum examination was appropriate to assess cervical status, but digital examination should be deferred until ultrasound confirms placental location 1.

Do not assume threatened abortion is benign without ultrasound confirmation of intrauterine pregnancy location and fetal viability, as clinical assessment has poor concordance (38.8%) with definitive diagnosis 2. Even with palpable uterus and fetal heart tones, ectopic pregnancy (though rare at this size) and other complications must be excluded 3, 7.

Ensure concrete follow-up plans are documented and understood before discharge, as approximately 15-20% of threatened abortions progress to pregnancy loss, and delayed recognition of complications can lead to significant morbidity 1, 2.

Prognosis and Counseling

With a closed cervix, normal fetal heart tones, and hemodynamic stability, the prognosis is generally favorable, though approximately 15-20% of threatened abortions may still progress to pregnancy loss 2, 4. Counsel the patient that bleeding may continue for several days but should gradually decrease 4. The presence of fetal cardiac activity is the most important prognostic indicator for continued pregnancy viability 4.