Differentials
Hyperemesis gravidarum
SIGNS / SYMPTOMS
A common presenting symptom. Nausea and vomiting might develop earlier and be more severe because of unusually high hCG levels.
INVESTIGATIONS
Routine early maternal screening ultrasound has enabled earlier diagnosis of molar pregnancy, before severe clinical symptoms develop. Hyperemesis associated with a molar gestation resolves promptly after evacuation, roughly in parallel to the decline in hCG levels.
Spontaneous abortion
SIGNS / SYMPTOMS
Risk factors include older parental age, infection, and thrombophilias.
Cramp-like discomfort may signify the process of expulsion of the fetus.
INVESTIGATIONS
Ultrasound findings of a complete mole are characteristically different from spontaneous abortion. A partial mole may contain a fetal pole or fetus, usually without cardiac activity, and may be more difficult to discriminate from a missed abortion.
Inspection of evacuated tissue for hydropic villi, and chromosome testing of evacuated tissue may be confirmatory.
Multiple gestation
SIGNS / SYMPTOMS
The uterus is larger than expected for dates, and there is an elevated serum hCG level with corresponding symptoms of nausea and emesis. Multiple gestations can be complicated with a complete or partial mole and a co-existing viable fetus, but it is rare for molar pregnancies to be associated with multiple gestation.
INVESTIGATIONS
Ultrasound with uterine enlargement greater than expected for gestational age and multiple fetuses.
Ovarian cysts
SIGNS / SYMPTOMS
Elevated levels of hCG or hypersensitivity to hCG causes gross cystic enlargement of the ovaries. Ovarian cysts may present with pelvic or abdominal masses or ovarian torsion. Pelvic pressure and abdominal extension are common. The theca lutein cysts of molar pregnancies are typically a painful condition.
INVESTIGATIONS
Theca lutein cysts are difficult to diagnose by palpation because of uterine enlargement. However, ultrasound identifies enlarged ovaries with cysts >6 cm in diameter. After evacuation of the MP, ovarian cysts spontaneously regress within about 12 weeks.
Uterine fibroids
SIGNS / SYMPTOMS
Symptoms include an enlarged uterus on exam, pelvic pain and pressure, and bleeding.
INVESTIGATIONS
Pelvic ultrasound shows well-defined uterine tumors.
Hyperthyroidism
SIGNS / SYMPTOMS
History of heat intolerance, palpitations, and anxiety.
INVESTIGATIONS
Enlarged and possibly tender thyroid and thyroid nodules on palpation.
Decreased thyroid-stimulating hormone and elevated thyroxine (T4).
Preeclampsia
SIGNS / SYMPTOMS
New-onset, persistent hypertension (defined as a systolic blood pressure ≥140 mmHg and/or a diastolic blood pressure ≥90 mmHg), usually after 20 weeks’ gestation, with new-onset proteinuria (protein:creatinine ratio of ≥0.3 and albumin:creatinine ratio of ≥8 mg/mmol) or evidence of systemic involvement.
INVESTIGATIONS
In molar pregnancy, symptoms of preeclampsia might develop earlier and be more severe because of unusually high hCG levels.
Ectopic pregnancy
SIGNS / SYMPTOMS
Missed menstrual period, lower quadrant pain, or pelvic pain with some degree of vaginal bleeding or spotting. Cervical motion tenderness may be present on pelvic exam.
INVESTIGATIONS
Elevated hCG levels.
Ultrasound reveals an empty uterus and may show a mass in the fallopian tubes.
Pelvic tumor
SIGNS / SYMPTOMS
May present with an enlarged uterus and painless bleeding of uterine and adnexal masses.
Nausea, emesis, and hyperthyroidism are not typically seen in pelvic malignancies.
INVESTIGATIONS
Serum hCG levels are rarely elevated with pelvic tumors.
Ultrasound of the pelvis demonstrates a uterine mass or abnormal adnexal organs.
Pelvic computed tomography generally is diagnostic.
Pathology of the products of dilation and suction evacuation may confirm tumor histology.
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