Androstenedione, testosterone, progesterone and human chorionic gonadotrophin (HCG) in plasma and total oestrogens, luteinizing hormone (LH) and HCG in urine were measured in five women during conceptual cycles and in early pregnancy. There were increased levels in plasma and urine of all the hormones measured between 12 to 48 days after ovulation except progesterone. The concentration of this hormone in plasma decreased during this time. The possible sources of these hormones in early pregnancy are discussed.