Effects of the progestasert® on the menstrual pattern, ovarian steroids and endometrium

Abstract

Clinical studies with the new progesterone-releasing intrauterine device (Progestasert) were done in 192 women with follow-ups at 6 and 12 months, accumulating a total of 1,823 women months. 108 were nulliparous and 84 were parous. Our study shows 0.5 pregnancies per 100 women years during the first 12 months of its use, which is considerably lower than previously reported. The overall expulsion rate was 7.4 per 100 women years, with 4.8 and 10.7 corresponding to nulliparous and parous women, respectively. It was of significance to note that most expulsions (77%) occurred within one month after insertion. Intermenstrual spotting or bleeding constituted the major side effect of the system; yet, the amount was small and mostly limited to the first two months of its use. It was observed that the amount of menstrual flow and dysmenorrhea were significantly reduced in 20–30% of patients, including those women who had a history of heavy menstrual flow and dysmenorrhea prior to the insertion of the Progestasert. The overall continuation rate was 76.0 ± 3.2 with 79.2 ± 4.1 for the nulliparous women, and 71.7 ± 5.0 for the parous; thus the Progestasert is evidently suitable for both nulliparous and parous women. Serum steroid assays showed a normal ovulatory function. The effect of the Progestasert on the endometrium was observed in biopsies performed at 12 months, which generally displayed glandular atrophy and decidual reaction, regardless of the phase of the cycle. The new concept of combining IUDs with locally delivered steroidal compounds offers advantages, but the long range results rely on continuous clinical observations comprising a large population of many years of use.