Placental protein 14 (PP14) and human chorionic gonadotrophin (HCG) were analysed in patients participating in an in-vitro fertilization-embryo transfer programme which did not include any kind of luteal support. Women with normal pregnancies, spontaneous abortions, ectopic pregnancies, biochemical pregnancies and non-pregnant women were compared. A combination of HCG and PP14 analyses distinguished between normal and abnormal implantation as early as 15 days after oocyte retrieval. The product of HCG (IU/l) and PP14 (micrograms/l) concentrations differed significantly between normal pregnancy, spontaneous abortion and ectopic pregnancy (P = 0.0248). It is concluded that both endometrial (PP14) and trophoblastic (HCG) markers, when used in combination, exhibit changes in abnormal implantation which may be clinically useful.