Suitable biological methods for the estimation of human chorionic gonadotrophin (hcg) in body fluids include those involving ovarian hyperaemia and prostatic weight in rats. Immunological assays depending on haemagglutination-inhibition and complementfixation tests lack specificity and cannot be recommended for the quantitative determination of the hormone.
In normal pregnancy hcg levels are high in the first trimester and much lower in the second and third trimesters. hcg activity appears in urine shortly after conception and disappears rapidly following delivery.
In patients with hydatidiform mole hcg levels in body fluids are generally but not invariably well above the normal range. Following surgical treatment of mole and of trophoblastic tumours of the uterus hcg assays may be a valuable guide to prognosis.
hcg readings in blood and urine are often abnormally high in women with severe pre-eclamptic toxaemia. In mild and moderate toxaemia levels are generally within the normal range.
Patients with hyperemesis gravidarum usually fail to show the peak period of hcg excretion in early pregnancy. hcg readings in such cases bear no definite relationship to the duration and severity of the vomiting.
In diabetic pregnancy and in threatened and habitual abortion assays of hcg are of little diagnostic or prognostic value. The administration of stilboestrol to pregnant diabetics causes a transient fall in hcg output.
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