What is the likely diagnosis for a 3-month pregnant patient presenting with vaginal spotting, abdominal cramps, a closed cervix, and a uterus size consistent with gestational age?

Molar Pregnancy (Gestational Trophoblastic Disease)

The most likely diagnosis is molar pregnancy (option b), given the critical finding of a uterus palpated at the umbilicus in a patient reporting 3 months gestation—this represents size-dates discrepancy that is pathognomonic for molar pregnancy.

Key Diagnostic Features Supporting Molar Pregnancy

Size-Dates Discrepancy

• A uterus at the umbilical level corresponds to approximately 20 weeks gestational size, yet the patient reports only 3 months (12 weeks) pregnancy 1
• This marked discrepancy between reported gestational age and actual uterine size is the hallmark clinical finding of complete molar pregnancy 1
• The excessive uterine enlargement results from proliferating trophoblastic tissue and accumulated fluid 1

Clinical Presentation Consistent with Molar Pregnancy

• Vaginal spotting with minimal blood-stained discharge is a common presenting symptom of molar pregnancy 2
• Abdominal cramping can occur as the uterus expands rapidly 3
• Closed cervix indicates the pregnancy has not yet progressed to expulsion 3, 4
• Stable vital signs (BP 110/80, HR 88, afebrile) are typical in early molar pregnancy before complications develop 2

Why Other Options Are Less Likely

Incomplete Abortion (Option d) - Excluded

• Incomplete abortion typically presents with an open cervix with products of conception visible or protruding through the cervical os 4
• The uterus size would be smaller than expected for gestational age, not larger 3
• This patient has a closed cervix and enlarged uterus, making incomplete abortion incompatible 4

Ectopic Pregnancy (Option e) - Excluded

• Ectopic pregnancy presents with a uterus that is smaller than expected for dates, not larger 5, 6
• The most common finding is a complex adnexal mass (75% of cases), not an enlarged uterus 5
• At 3 months gestation, an unruptured ectopic would have already caused significant symptoms and likely rupture 6

Breech Pregnancy (Option c) - Not Applicable

• Fetal presentation cannot be determined at 12 weeks gestation and is irrelevant to the clinical scenario 7
• Breech presentation does not cause size-dates discrepancy or vaginal bleeding 7

Hydrops Pregnancy (Option a) - Less Likely

• While hydrops can cause uterine enlargement, it typically occurs later in pregnancy (second/third trimester) 7
• Hydrops would not explain the degree of size-dates discrepancy seen here 1

Critical Next Steps

Immediate Diagnostic Evaluation Required

• Ultrasound examination is mandatory to confirm molar pregnancy and visualize the characteristic "snowstorm" or "bunch of grapes" appearance 2
• Transvaginal ultrasound provides superior resolution for first trimester evaluation 8, 2
• Quantitative beta-hCG levels should be obtained—molar pregnancy typically shows markedly elevated levels (often >100,000 mIU/mL) 8

Important Clinical Caveat

• Digital pelvic examination should be avoided until ultrasound excludes placenta previa and vasa previa, though less likely at this gestational age 8, 7
• The patient requires urgent referral to gynecology or early pregnancy assessment service for definitive diagnosis and management 6
• Molar pregnancy requires evacuation and long-term beta-hCG monitoring due to risk of persistent gestational trophoblastic disease and malignant transformation 1