Synopsis
Recognise when severe vomiting, uterine size discordance or thyroid findings indicate excessive trophoblastic activity and require urgent assessment for molar pregnancy.
- Nausea and vomiting are common in early pregnancy, but weight loss, dehydration, electrolyte imbalance and functional impairment define a more severe clinical problem requiring structured assessment.
- A molar pregnancy is one secondary cause of severe or unusually early hyperemesis; ask about bleeding, pelvic pressure, dates, previous mole and symptoms of thyroid or hypertensive disease.
- Compare uterine size with reliable gestation and scan rather than dates alone: a uterus larger than expected may reflect multiple pregnancy, fibroids, incorrect dates or abundant molar tissue.
- High hCG can stimulate thyroid receptors, producing suppressed TSH and raised free hormones; many patients lack Graves-specific signs and improve after trophoblastic tissue is treated.
- Clinical thyrotoxicosis matters more than an isolated low TSH in the first trimester; look for persistent resting tachycardia, tremor, heat intolerance, goitre, eye signs, heart failure and arrhythmia.
- Ultrasound, quantitative hCG and histology are complementary: none of vomiting, uterine size or thyroid tests alone diagnoses a mole.
- Correct dehydration and electrolyte deficits, give thiamine before dextrose after prolonged vomiting, use pregnancy-appropriate antiemetic care, offer low-molecular-weight heparin to admitted patients unless contraindicated, and involve specialists before evacuation if severe thyrotoxicosis is present.
- A normal-sized uterus or hCG within the broad gestational range does not exclude partial mole, which commonly presents like miscarriage and is diagnosed on tissue histology.
Key red flags
Hypotension, persistent tachycardia, oliguria, syncope or inability to retain fluids indicates significant volume depletion and usually requires hospital assessment.
Confusion, ataxia, ocular signs or profound weakness after prolonged vomiting suggests thiamine deficiency or major electrolyte disturbance and needs immediate treatment.
Fever, agitation, heart failure, atrial arrhythmia or severe tremor with raised thyroid hormones raises concern for thyroid storm rather than uncomplicated gestational biochemical change.
Uterine enlargement far beyond dates, early hypertension, bilateral ovarian enlargement or a markedly excessive hCG concentration should prompt urgent ultrasound for trophoblastic disease or multiple pregnancy.
Abdominal pain, peritonism, haemodynamic instability or unilateral adnexal findings require assessment for ectopic pregnancy, torsion, haemorrhage or another surgical cause.
Investigation priorities
Establish gestation, viability, fetal number, placental morphology and adnexal findings.
Management branches
A pregnant patient presents with persistent vomiting or inability to maintain oral fluids.
- Assess ABCDE, observations, hydration, weight change, urine output, abdominal and neurological findings, then obtain glucose, electrolytes and renal function urgently.
- Start isotonic intravenous fluid when clinically depleted, replace deficits with repeat testing and give thiamine before dextrose after sustained poor intake.
- Escalate immediately for confusion, major electrolyte disturbance, haematemesis, sepsis, surgical abdominal signs, cardiac failure or an unstable rhythm.