Levels of HCG in subjects using the Progestasert(TM) intrauterine progesterone systems.

Twelve subjects using the intrauterine progesterone system were followed during 4 consecutive menstrual cycles for FSH, LH, hCG and progesterone levels. They were all multiparous, with documented ovulation and sexually active even during the ovulatory period. With the exception of one case which became pregnant, there was no evidence for the presence of hCG during the period of observation. This data, even if preliminary, suggest that the Progestasert(TM) exerts a contraceptive action which differs from that of other devices, whether medicated or not, and that, such action occurs at a stage early enough to prevent the formation of hCG.