Abstract
Nestorone® progestin (NES) is a potent 19-nor-progesterone derivative which is biologically
inactive when administered orally; however, it is an excellent option for implant
contraception. The objective of this study was to evaluate ovarian function during
use of either one 4-cm or two 3-cm NES implants for 24 months. A total of 60 volunteers
were enrolled in each dose group. Vaginal ultrasound (VUS) and blood sampling for
determinations of estradiol (E2), progesterone (P) and NES serum levels were carried out twice a week for 6 consecutive
weeks, beginning in months 1, 6, 12, 18, and 24 of implant use. Serum levels of NES
declined with time, with a more pronounced decrease during the first 18 months of
implant use; thereafter, NES levels remained stable until the end of the study at
24 months. Luteal activity was very infrequent during the first year of use (<3%)
but increased during the second year, occurring in 27% and 35% of the sampling periods
in the 1-implant group, and 2% and 16% of the sampling periods in the 2-implant group,
at months 18 and 24 of use, respectively. No luteal activity was observed with NES
levels above 80 pmol/L. Serum P levels in periods of luteal activity were significantly
lower than those of controls. Persistent anovulatory follicles were the most common
VUS finding and this was associated with E2 levels that remained within the normal range (101–1500 pmol/L) in the majority of
the sampling periods studied. Considering that a single implant offers advantage for
insertion and removal, a new single NES implant is being developed with a slightly
higher release rate, to reduce effectively the incidence of ovulation and provide
a greater margin of safety beyond 2 years.
Keywords
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References
- Norplant® consensus statement and background review.Contraception. 1998; 57: 1-9
- Recent experience with and future directions of contraceptive implants and injectable contraceptives.Curr Opin Obstet Gynecol. 1993; 5: 805-814
- Contraceptive implants.Curr Opin Obstet Gynecol. 1994; 6: 564-569
- Fertility control with subdermal Silastic capsules containing a new progestin (ST-1435).Int J Fertil. 1976; 21: 103-108
- Pituitary and ovarian function during contraception with one subcutaneous implant releasing a progestin, ST 1435.Contraception. 1982; 25: 299-306
- Contraception with subdermal ST-1435 capsules.Contraception. 1985; 31: 305-318
- Concentration-dependent mechanisms of ovulation inhibition by the progestin ST-1435.Fertil Steril. 1985; 44: 20-24
- A contraceptive subdermal implant releasing the progestin ST-1435.Fertil Steril. 1992; 58: 1142-1147
- Contraception with subdermal implants releasing the progestin ST-1435.Contraception. 1992; 45: 49-55
- Clinical trial with Nestorone subdermal contraceptive implants.Contraception. 1995; 51: 33-38
WHO Special Programme of Research, Development and Research Training in Human Reproduction. Programme for the Provision of Matched Assay Reagents for the RIA of Hormones in Reproductive Physiology, 16th ed, Method Manual. Sufi SB. Donaldson A, Jeffcoate SL, WHO Collaborating Centre for Immunoassay, London, UK, 1992.
- Contraception with subcutaneous capsules containing ST-1435. Pituitary and ovarian function and plasma levels of ST-1435.Contraception. 1981; 23: 63-75
- A method for labeling oestradiol-17β with radioiodine for radioimmunoassay.J Endocrinol. 1973; 37: 47
- Ovarian function during the use of a single contraceptive implant.Fertil Steril. 1998; 69: 714-721
- Effects of a single contraceptive Silastic implant containing nomegestrol acetate on ovarian function and cervical mucus production during 2 years.Fertil Steril. 1996; 65: 724-729
- Hormonal profile, endometrial histology and ovarian ultrasound assessment during 1 year of nomegestrol acetate implant (Uniplant).Hum Reprod. 1997; 12: 708-713
- Plasma progesterone levels during long-term treatment with levonorgestrel Silastic implants.Acta Endocrinol (Copenh). 1982; 101: 307-311
- Ovarian endocrine function through five years continuous treatment with Norplant® subdermal implants.Contraception. 1990; 41: 160-177
- Clinical performance of a new two-rod levonorgestrel contraceptive implant.Contraception. 1997; 55: 73-80
- Levonorgestrel capsule implants in the United States.Obstet Gynecol. 1998; 92: 337-344
- Estradiol plasma levels during long-term treatment with Norplant® subdermal implants.Contraception. 1988; 38: 465-474
- Pharmacodynamics of a contraceptive vaginal ring releasing 3-keto-desogestrel.Contraception. 1989; 39: 653-664
- Characteristics of ovarian follicular development in Norplant® implants users.Fertil Steril. 1991; 55: 766-770
- Sonographic assessment of ovarian and endometrial changes during long-term Norplant® use and their correlation with hormonal levels.Fertil Steril. 1993; 59: 998-1002
- Ultrasonographic and endocrine evaluation of ovarian function among Norplant® implants users with regular menses.Contraception. 1996; 54: 275-279
- Ultrasonographic monitoring of ovarian follicles in women using norethisterone for contraception.Int J Gynecol Obstet. 1996; 53: 31-34
- Inhibition of the positive feedback of estradiol during treatment with subcutaneous implants of d-norgestrel.Contraception. 1976; 13: 287-297
- Functional life-span of the dominant follicle in pharmacologically induced anovulatory cycles.Hum Reprod. 1996; 11: 114-116
- The pharmacodynamics and efficacy of Implanon®. An overview of the data.Contraception. 1998; 58: 91S-97S
- Milk and plasma concentrations of the progestin ST-1435 in women treated parenterally with ST-1435.Contraception. 1990; 42: 555-562
- Contraception in lactating women.Curr Opin Obstet Gynecol. 1993; 5: 815-822
- Unaltered lipoprotein and carbohydrate metabolism during treatment with contraceptive subdermal implants containing ST-1435.Contraception. 1985; 31: 123-130
- Serum lipids, blood pressure, body weight, and serum chemistry in women using subcutaneous contraceptive implants releasing the progestin ST-1435.Obstet Gynecol. 1992; 80: 855-859
Why family planning matters. Population Reports1999, 25, Series J, No 49.
Article info
Publication history
Accepted:
February 7,
2000
Received in revised form:
January 27,
2000
Received:
December 15,
1999
Identification
Copyright
© 2000 Elsevier Science Inc. Published by Elsevier Inc. All rights reserved.
