Estrogen-progesterone withdrawal bleeding in diagnosis of early pregnancy.

This study was designed to evaluate the efficacy of an exogenous estrogen-progesterone preparation for inducing "withdrawal bleeding" in non-pregnant women, a procedure used in some areas for the diagnosis of early pregnancy. Three hundred patients not desiring to be pregnant and with no signs of pregnancy other than menses delayed by 14 days or less were randomly assigned to treatment or control groups. The treatment group received an intramuscular injection of 50 mg progesterone and 3 mg oestradiol benzoate in oil. The control group received no hormonal injection. There was no significant difference between the two groups in the incidence of uterine bleeding within 7 days. Thus, the hormonal preparation was ineffective in inducing "withdrawal bleeding". Its use as a diagnostic test for pregnancy is not recommended.