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Timing of onset of contraceptive effectiveness in Norplant® implant users II
ORIGINAL RESEARCH ARTICLE
Timing of Onset of Contraceptive Effectiveness in Norplant威 Implant Users II Effect on the Ovarian Function in the First Cycle of Use Vivian Brache,* Paul D. Blumenthal,† Francisco Alvarez,* Thomas R. Dunson,‡ Leila Cochon,* and Anibal Faundes§
The objective of this study was to time the onset of contraceptive effectiveness in Norplant威 implant users, when the capsules were inserted beyond the first 7 days of the cycle, based on the immediate effect on the ovarian activity. A total of 42 healthy women requesting Norplant implant contraception were enrolled at clinics in Santo Domingo, Dominican Republic, and in Baltimore, Maryland. Implants were inserted on days 8 –13 of the menstrual cycle. Blood samples for estradiol (E2), progesterone ( P), luteinizing hormone (LH) (in a subset of 12 women), and levonogestrel (LNG) assay, were taken at 0 h and at 6, 12, 24, 72, and 168 h postinsertion. Ovulation, as defined by P ⬎2.5 ng/mL, occurred in 40% of subjects. A short lasting, frequently blunted, LH peak occurred within 12 h postinsertion, in all these subjects. The remaining subjects had anovulatory cycles with two distinct E2 profiles: continuously increasing E2 levels to a high mean of 414.3 pg/mL (28%), or no sustained increase in E2 (32%). Most cycles (86%) in which Norplant was inserted with high E2 levels (⬎175 pg/mL) were ovulatory, whereas none were ovulatory with low E2 (⬍100 pg/mL) at insertion. Based on the endocrine effects of Norplant implant insertion in the midadvanced follicular phase, in which ovulation will either occur within 48 h of insertion or will be impaired, additional contraceptive protection is necessary only for 3 days. CONTRACEPTION 1999;59:245–251 © 1999 Elsevier Science Inc. All rights reserved. KEY WORDS:
Norplant威, back-up contraception, ovulation inhibition, luteinizing hormone peak
*PROFAMILA, Santo Domingo, Dominican Republic; †Johns Hopkins Bayview Medical Center, Baltimore, Maryland; ‡Family Health International, Research Triangle Park, North Carolina; and §Centro de Pesquisas de Doenc¸as MaternoInfantis de Campinas (CEMICAMP), Campinas, Sao Paulo, Brasil Name and address for correspondence: Vivian Brache, Biomedical Research Department, PROFAMILIA, P.O. Box 1053, Santo Domingo, Dominican Republic. Submitted for publication February 23, 1999 Revised April 15, 1999 Accepted for publication April 15, 1999
© 1999 Elsevier Science Inc. All rights reserved. 655 Avenue of the Americas, New York, NY 10010
Introduction The contraceptive efficacy and acceptability of Norplant威 subdermal implants have been extensively documented.1,2 Several studies have shown that the main mechanisms of action of this progestin-only, long acting method are ovulation inhibition or dysfunction and deleterious effects on cervical mucus rendering sperm penetration difficult.3–12 However, the majority of these studies have been conducted during long-term use. Initial studies showed that, when the implants are inserted in the first 7 days of the cycle, ovulation inhibition is achieved in the first cycle.13,14 However, limiting insertion to the first 7 days of the cycle may hinder the woman’s access to adequate contraception; therefore, current clinical guidelines state that implants may be inserted at any time in the cycle, provided that there is reasonable assurance that the woman is not pregnant and that a back-up method is used for the first week.15,16 To better define the length of time that backup contraception would be needed when inserting Norplant implants beyond the first 7 days of the menstrual cycle, we undertook this clinical study, which was designed to time the onset of contraceptive effectiveness in Norplant implant users when inserted in the midadvanced follicular phase (days 8 –13 of the cycle). The outcome measures of interest were indicators of ovulation inhibition in the same cycle of use and changes in cervical mucus in the first week of use. The first report in this series, which examined the effect on cervical mucus in the first hours to days postinsertion, has recently been published.17 This report is the second in this series and focuses on the effect of levonorgestrel over the ovarian function in the first cycle postinsertion. ISSN 0010-7824/99/$20.00 PII S0010-7824(99)00028-1
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Materials and Methods Study Information The methods, study design, schedule of visits, and subject characteristics have been previously described.16 Briefly, this study was designed as a prospective, descriptive investigation with the objective to obtain scientific data on the changes in cervical mucus and key hormones within the first hours to days after Norplant implant insertion, and to better estimate when the cervical and hormonal environments were hostile enough to suggest impaired fertility. A total of 42 women who were between days 8 and 13 of their menstrual cycle and who had requested Norplant implants were admitted to the study at two reproductive health clinics: one in Santo Domingo, Dominican Republic, and the other in Baltimore, Maryland. Volunteers had to be abstinent or use nonspermicidal condoms for the duration of the study. Subjects made up to five follow-up visits postinsertion (6, 12, and 24 h postinsertion, and days 3 and 7 postinsertion). Cervical mucus and blood samples were obtained with the primary outcome measures being cervical mucus scores, sperm penetration distances, and serum levels of progesterone (P), estradiol (E2), and levonorgestrel (LNG). Estradiol and progesterone were assayed in samples taken before insertion (hour 0) and on days 1, 3, and 7 postinsertion. Two subjects (both in day 13 of the cycle) had baseline progesterone levels above 2.5 ng/mL (3.6 and 21.2 ng/mL), indicative of prior ovulation, and were therefore excluded from this analysis. Levonorgestrel was assayed in the blood samples taken at each visit. LH was assayed only in the 12 women at the Santo Domingo clinic who showed increase in P levels indicative of luteal activity (P ⬎2.5 ng/mL). Progesterone levels ⬎2.5 ng/mL was used as an indicator of ovulation, considering that the sampling period was short (7 days) and did not cover the entire luteal phase.
Hormone Assays Samples from both centers were shipped to the Steroid Research Laboratory in Helsinki, Finland for central analysis of E2, P, and LNG. Estradiol was determined by radioimmunoassay according to the protocol from the World Health Organization, with an intraassay coefficient of variation (CV) of 5.0%– 7.3% and an interassay CV of 10.4%–16.6%. Progesterone was determined by a time resolved solid phase fluoroimmunoassay (Delfia, Wallac Oy Pharmacia, Turku, Finland) with an intra- and interassay CV of 3.3%–7.3% and 2.7%–10.1%, respectively. Levonorgestrel was measured by radioimmunoassay with tri-
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tium labeled levonorgestrel as tracer, as described by Weiner and Johansson.13 The intra- and interassay CV varied from 2.3% to 6.3% and from 7.9% to 12.0%, respectively. LH was determined locally at the laboratory of the Department of Biomedical Research of PROFAMILIA in Santo Domingo by an enzyme immunoassay (EIA) provided by the World Health Organization Matched Reagent Programme (Geneva, Switzerland) standardized against International Reference Preparation 80/552 and with an intra- and interassay CV of 2.4% and 9.4%, respectively. The 2 test was used to test whether there was an association between estradiol levels at the moment of insertion and subsequent ovarian profile.
Results The 40 subjects enrolled ranged in age from 18 to 33 years, with a mean of 23.8 years. Their average weight was 57.9 kg, with a range of 40.0 – 83.6 kg. Of the insertions, 15% were done on day 8/9 (n ⫽ 6), 32% on day 10/11 (n ⫽ 13), and 53% on day 12/13 (n ⫽ 21). Upon evaluation of the hormonal results, three distinct ovarian profiles were observed after Norplant implants insertion. Two of these profiles were anovulatory (P ⬍2.5 ng/mL): profile A was characterized by no sustained postinsertion increase in E2 levels, whereas profile B was characterized by a continuous rise in E2 (⬎250 pg/mL). The third profile (profile C), was defined as having “luteal activity”; in these subjects, progesterone levels rose to ⱖ2.5 ng/mL and the majority most likely corresponded to ovulations. Of the 40 women enrolled, profile A was observed in 13 women (32%) and profile B in 11 (28%), whereas luteal activity (profile C) was observed in 16 (40%). Subjects with profile A had the lowest preinsertion mean E2 (82.2 ⫾ 17.1 pg/mL), with no sustained postinsertion increase in serum levels, as shown by a mean of 85 pg/mL on day 7 postinsertion. Mean P levels in this group, remained ⬍0.5 ng/mL throughout the study (Figure 1). Subjects with profile B had a mean E2 level of 132.5 ⫾ 42.1 pg/mL at insertion and exhibited a continuous and pronounced rise, reaching a mean of 414.3 pg/mL at Day 7 postinsertion, with a mean P level of 0.7 ng/mL on this same day. Subjects with luteal activity (profile C) had the highest mean estradiol levels before insertion (210.1 ⫾ 71.5 pg/mL), followed by a drop to 191.8 pg/mL and 113.7 pg/mL on day 1 and day 3 postinsertion, respectively. A slight rise to 148.4 pg/mL was observed on day 7. The mean P levels among these 16 subjects with luteal activity reached 2.7 ⫾ 1.6 and 8.5 ⫾ 3.4 ng/mL on day 3 and day 7 postinsertion, respectively. However, four of these subjects had progesterone levels ⬍6 ng/mL at
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Figure 1. Different ovarian profiles observed in first cycle of use after Norplant implant insertion on days 8 –13 of the follicular phase.
day 7, suggestive of luteal insufficiency or luteinized unruptured follicle (LUF). Of the 16 subjects with luteal activity, 12 were from Santo Domingo and four from the Baltimore clinic. LH was measured in all 12 subjects from the Santo Domingo clinic, but additional serum from the Baltimore women was not available for this assay. Two women already had an elevated LH peak at the time of insertion (55.9 and 56.6 IU/L), which decreased to ⬍10 IU/L by 24 h postinsertion. In five other subjects, the onset of the LH surge was probably in progress at insertion, with values between 9.0 and 18.3 IU/L, followed by a short-lived peak that occurred within 12 h (31– 66 IU/L) and that had dropped in all instances by 24 h postinsertion. The five remaining subjects had low LH levels at time 0 (⬍7
IU/L), followed by a small surge also within 12 h (8.0 –19.7 IU/L, 143%– 650% increase from time 0), and returning to baseline levels by 24 h postinsertion. (Table 1). In one of these last cases a second LH elevation was observed on day 3 (14.5 IU/L) that was higher than that seen at 12 h (9 IU/L). If sampling had been taken only every 24 h, no LH surge (⬎20 IU/L) would have been detected in any of the subjects, except in the two women who already had an LH peak at the time of insertion (⬎50 IU/L). Figure 2 shows the percentage of cycles with luteal activity according to the day of cycle in which the insertion was done. No luteal activity was observed among the six women in whom insertions were done before day 10 of the cycle; however, the percentage of cycles with luteal activity ranged between 38% and
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Table 1. LH levels (IU/L) at 0, 6, 12, 24, and 72 h after Norplant implant insertion in women with luteal activity Subject no. 16 10 28 6 4 23 22 2 20 33 27 13
0h
6h
12 h
24 h
72 h
1.4 2.6 3.0 4.1 6.7 9.3 9.4 10.1 14.1 18.3 (55.9) 56.6
4.1 (19.7) (9.0) 11.7 11.4 (38.7) (58.2) 21.8 6.0 (30.7) 14.6 (91.4)
(8.0) 12.8 7.0 (15.0) (16.3) 34.9 35.4 (46.0) (65.7) 19.6 6.0 70.3
5.4 3.5 3.8 4.9 6.2 5.8 7.2 19.9 12.1 7.4 2.6 7.6
6.8 6.0 14.5 5.4 11.3 13.4 10.3 23.3 22.7 7.7 6.2 11.6
LH peaks in parentheses.
60% when implants were inserted between days 10 and 13 of the cycle. Table 2 shows the percentage of women in each profile, according to E2 level at insertion. A very clear correlation was found between estradiol levels at insertion and subsequent ovarian profile: profile A (no sustained increase in E2 and no luteal activity) was observed in 83% of the women with low E2 levels at insertion (⬍100 pg/mL) and in none of those with high E2 levels preinsertion (⬎175 pg/mL). On the other hand, luteal activity occurred in 86% of the cycles in which estradiol levels were ⬎175 pg/mL at the moment of insertion, whereas it did not occur in any woman who had E2 levels ⬍100 pg/mL at insertion (p ⫽ 0.0000). Levonorgestrel levels rapidly attained a mean value
Figure 2. Percentage of cycles with luteal activity according to day of cycle in which Norplant implants were inserted.
above 600 pg/mL at 6 h postinsertion, further increasing to above 900 pg/mL at 24 h, and still remaining near those levels at days 3 and 7 postinsertion (Figure 3). Although significant variability existed between subjects, no significant difference in levonorgestrel levels was observed among the three distinct groups of ovarian profile.
Discussion The data presented here indicate that the effect of the initial administration of levonorgestrel on the menstrual cycle depends on the degree of follicular development existing at the moment of insertion. Our results, when considered with those of previous studies of the endocrine profile and follicular development in women during long-term use of Norplant,8,10,11 suggest the following sequence: if the follicular development is at an early stage, based on low E2 levels (⬍100 pg/mL), the follicular development will be interrupted. When an intermediate degree of development has been attained, the follicle will continue to grow, with increasing high estradiol levels but without subsequent rupture or luteinization. If the follicle has reached preovulatory development, a short-lived LH surge will follow shortly, within the first 12 h of insertion, followed by luteal activity (either LUF or ovulation). Forty percent of the subjects, those who appear to have ovulated after insertion, may have required another form of contraception. All of them had a LH surge within 12 h after insertion. Considering that ovulation occurs around 9 –10 h after the LH peak, with an upper variability of about 24 h,18 –20 and considering that conception is highly unlikely 24 h after ovulation,21 it seems that 3 days of additional protection would be sufficient in women. Furthermore, the normal mean duration of the LH surge is 48 –50 h,22,23 and studies show that a shortlived surge may be incompatible with pregnancy
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Table 2. Percent distribution of women in each ovarian profile stratified by estradiol (E2) (pg/mL) levels at insertion
Ovarian profile after insertion Profile A (no further E2 increase, no luteal activity) Profile B (E2 sustained increase, no luteal activity) Profile C (luteal activity)
E2
Total no. (%)
<100
100–175
>175
13/40 (32%) 11/40 (28%) 16/40 (40%)
10/12 (83%) 2/12 (17%) 0/12 (0%)
3/14 (21%) 7/14 (50%) 4/14 (29%)
0/14 (0%) 2/14 (14%) 12/14 (86%)
p ⫽ 0.0000.
because of the lack of oocyte maturation or inadequate corpus luteum development and function.24,25 This study confirms the observation that levonorgestrel seems to accelerate the appearance of a shortlived, frequently blunted LH peak when sufficient estradiol priming has occurred.26 Other reports have shown the importance of the progestational signal after an E2 increase to induce the LH surge.22,27–29 Evidence exists that the administration of mifepristone in the late follicular phase delays the LH surge by antagonizing the progestational signal.30 –32 Furthermore, in phase I studies testing the contraceptive feasibility of a combination of mifepristone/progestin sequential regimens, the progestin administered after 15 consecutive days of mifepristone use appeared to trigger a pituitary gonadotrophin surge.33,34 In a similarly designed protocol, Petta et al. report on the effect of the injection of 150 mg of depot medroxyprogesterone acetate (DMPA), on days 8 –13 of the cycle, on the ovarian function in the first month of use. Thirty percent of the subjects ovulated, and high E2 levels were also shown to be an indicator
of subsequent follicular rupture. Ovulation only occurred among women who had E2 levels of ⱖ100 pg/mL. Follicular rupture, as documented by ultrasound observations, had occurred in all women by day 3 after DMPA administration. These authors also conclude that DMPA may trigger the ovulatory mechanism.35 In summary, the data here presented suggests that two possible ovulatory dysfunctions with a contraceptive effect follow Norplant implants insertion in the second half of the follicular phase of the cycle: 1) inhibition of ovulation, with or without continued follicle development; or 2) induction of a blunted LH peak in amplitude and duration. This blunted LH peak is characteristically observed among ovulating, long-term Norplant implant users, who are considered to be well protected against pregnancy.7,9,11 On the other hand, if the LH surge is already well underway, a normal LH peak may occur within the 12 h after insertion of the implants. When the latter condition is present, the woman will not be protected against pregnancy for the first 2 or 3 days after implant insertion.
Figure 3. Serum levonorgestrel levels in the first week after insertion of Norplant subdermal implants.
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In conclusion, considering the immediate endocrine effects of Norplant implants when inserted in the midadvanced follicular phase, irrespective of the day of the cycle, additional protection is recommended for 3 days only. This recommendation is further reinforced by the progestagenic changes observed in the cervical mucus and adverse effects on sperm penetration reported in the same group of women within 3 days after Norplant implant insertion.17 This study also demonstrates the immediate contraceptive effect of Norplant implant when implants are inserted within the first 7 days of the cycle, a period in which E2 levels are low, and backup contraception is not required. This window could probably be extended through day 9, inasmuch as ovulations did not occur among six women in which insertions took place on day 8/9. However, because the number of women in this study is small, the burden of an unwanted pregnancy is high, and the inconvenience of 3 days of additional back-up protection is minimal, it seems appropriate to retain the conservative approach of using additional means of protection for 3 days when insertion has been performed beyond the first 7 days of the cycle.
Acknowledgments We acknowledge and are grateful to Irving Sivin for assistance in the statistical analysis and to Laneta Dorflinger and Lucinda Glover for comments on the draft manuscript. Partial support for this work was provided by Family Health International (FHI; Research Triangle Park, North Carolina) with funds from the US Agency of International Development (USAID), although the views expressed in this article do not necessarily reflect those of USAID. FHI is an international nonprofit organization that conducts research and provides technical assistance in reproductive health, family planning, sexually transmitted diseases, and AIDS.
References 1. Sivin I. International experience with Norplant implants and Norplant implants-2 contraceptives. Stud Fam Plann 1988;19:81–94. 2. Fraser IS, Tiitinen A, Affandi, B et al. Norplant威 consensus statement and background review. Contraception 1998;57:1–9. 3. Croxatto HB, Diaz S, Pavez M, Mirda P, Brandeis A. Plasma progesterone levels during long-term treatment with levonorgestrel Silastic implants. Acta Endocrinol 1982;101:307–11. 4. Brache V, Fau´ndes A, Johansson E, Alvarez F. Anovulation, inadequate luteal phase and poor sperm penetration in cervical mucus during prolonged use of Norplant implants. Contraception 1985;31:261–73.
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5. Alvarez F, Brache V, Tejada AS, Fau´ndes A. Abnormal endocrine profile among women with confirmed or presumed ovulation during long-term Norplant implants use. Contraception 1986;33:111–9. 6. Brache V, Alvarez F, Fau´ndes A, Tejada AS, Cocho´n L. Ovarian endocrine function through five years continuous treatment with Norplant subdermal implants. Contraception 1990;41:160 –77. 7. Olsson SE, Bakos O, Lindgren PG, Odlind V, Wide L. Ovarian function during use of subdermal implants releasing low doses of levonorgestrel. Br J Fam Plann 1990;16:88 –93. 8. Shoupe D, Horenstein J, Mishell DR Jr, Lacarra M, Medearis A. Characteristics of ovarian follicular development in Norplant implants users. Fertil Steril 1991; 55:766 –70. 9. Fau´ndes A, Brache V, Tejada AS, Cocho´n L, Alvarez F. Ovulatory dysfunction during continuous administration of low-dose levonorgestrel by subdermal implants. Fertil Steril 1991;56:27–31. 10. Shaaban MM, Segal S, Salem HT, Ghaneimah SA, Khalifa E-AM, Ahmed A-G. Sonographic assessment of ovarian and endometrial changes during long-term Norplant implants use and their correlation with hormonal levels. Fertil Steril 1993;59:998 –1002. 11. Alvarez F, Brache V, Faundes A, Tejada, AS, Thevenin F. Ultrasonographic and endocrine evaluation of ovarian function among Norplant implants users with regular menses. Contraception 1996;54:275–9. 12. Croxatto HB, Diaz S, Salvatierra AM, Morales P, Ebensperger C, Brandeis A. Treatment with Norplant subdermal implants inhibits sperm penetration through cervical mucus in vitro. Contraception 1987;36:193–201. 13. Weiner E, Johansson EDB. Plasma levels of d-norgestrel, estradiol and progesterone during treatment with Silastic implants containing d-norgestrel. Contraception 1976;14:81–92. 14. Moore DE, Roy S, Stanczyk FZ, Mishell DR, Jr. Bleeding and serum d-norgestrel, estradiol and progesterone patterns in women using d-norgestrel subdermal polysiloxane capsules for contraception. Contraception 1978;17:315–28. 15. Curtis, KM, Bright, PL, eds. Technical Guidance Working Group. Recommendations for updating selected practices in contraceptive use: results of a technical meeting. 1994. 16. McIntosh N, Riseborough P, Davis, C, eds. JHPIEGO Corporation. Norplant Implants Guidelines for Family Planning Service Programs, 2nd ed. 1995. 17. Dunson TR, Blumenthal, PD, Alvarez F, et al. Timing of onset of contraceptive effectiveness in Norplant implant users. I. Changes in cervical mucus. Fertil Steril 1998;69:258 – 66. 18. Paurstein CJ, Eddy CA, Croxatto HD, Hess R, SilerKhodr TM, Croxatto HB. Temporal relationships of estrogen, progesterone, and luteinizing hormone levels to ovulation in women and infrahuman primates. Am J Obstet Gynecol 1978;130:876 – 86. 19. World Health Organization Task Force Investigators. Temporal relationships between ovulation and defined  changes in the concentration of plasma estradiol-17, luteinizing hormone, follicle stimulating hormone, and progesterone. Am J Obstet Gynecol 1980; 138:383–90. 20. Garcia JE, Jones GS, Wright GL. Prediction of the time of ovulation. Fertil Steril 1981; 36:308 –15.
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21. Wilcox AJ, Weinberg CR, Baird DD. Timing of sexual intercourse in relation to ovulation. N Engl J Med 1995; 333:1517–21. 22. Hoff JD, Quigley ME, Yen SS. Hormonal dynamics at midcycle: a reevaluation. J Clin Endocrinol Metab 1983; 57:792– 6. 23. Fritz MA, McLachlan RI, Cohen NL, Dahl KD, Bremner WJ, Soules MR. Onset and characteristics of the midcycle surge in bioactive and immunoactive luteinizing hormone secretion in normal women: influence of physiological variations in periovulatory ovarian steroid hormone secretion. J Clin Endocrinol Metab 1992; 75:489 –93. 24. Zelinski-Wooten MB, Lazendorf SE, Wolf DP, AlainChadrasekher Y, Stouffer RL. Titrating luteinizing hormone surge requirements for ovulatory changes in primate follicles. I. Oocyte maturation and corpus luteum function. J Clin Endocrinol Metab 1991;73:577– 83. 25. Chandrasekher YA, Hutchison JS, Zelinski-Wooten MB, Hess DL, Wolf DP, Stouffer RL. Initiation of periovulatory events in primate follicles using recombinant and native human luteinizing hormone to mimic the midcycle gonadotropin surge. J Clin Endocrinol Metab 1994;79:298 –306 26. Brache, V, Alvarez, F, Faundes, A, Cochon, L, Thevenin, F. Effect of preovulatory insertion of Norplant implants over luteinizing hormone secretion and follicular development. Fertil Steril 1996;65:1110 – 4. 27. March CM, Goebelsmann U, Nakamura RM, Mishell DR Jr. Roles of estradiol and progesterone in eliciting the midcycle luteinizing hormone and follicle-stimulating hormone surges. J Clin Endocrinol Metab 1979; 49:507–11. 28. Permezel JM, Lenton EA, Roberts I, Cooke ID. Acute effects of progesterone and the antiprogestin RU 486 on
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gonadotropin secretion in the follicular phase of the menstrual cycle. J Clin Endocrinol Metab 1989;68: 960 –5. Batista MC, Cartledge TP, Zellmer AW, Nieman LK, Merriam GR, Loriaux DL. Evidence for a critical role of progesterone in the regulation of the midcycle gonadotropin surge and ovulation. J Clin Endocrinol Meta 1992;74:565–70. Shoupe D, Mishell DR Jr, Page MA, Madkour H, Spitz IM, Lobo RA. Effects of the antiprogesterone RU486 in normal women. II. Administration in the late follicular phase. Am J Obstet Gynecol 1987;157:1421– 6. Permezel JM, Lenton EA, Roberts I, Cooke ID. Acute effects of progesterone and the antiprogestin RU 486 on gonadotropin secretion in the follicular phase of the menstrual cycle. J Clin Endocrinol Metab 1989;68:960 –5. Batista MC, Cartledge TP, Zellmer AW, Niemar LK, Loriaux DL, Merriam GR. The antiprogestin RU486 delays the midcycle gonadotropin surge and ovulation in gonadotropin-releasing hormone-induced cycles. Fertil Steril 1994;62:28 –34. Croxatto HB, Massai MR, Salvatierra AW, Fuentealba B, Croxatto HD. Effects of a sequential regimen of mifepristone-medroxyprogesterone acetate on ovarian function, endometrial development, and hormonal parameters. Contraception 1996;54:79 – 86. Kekkonen R, Lahteenmaki P, Luukainen T, Tuominen J. Sequential regimen of the antiprogesterone RU486 and synthetic progestin for contraception. Fertil Steril 1993;60:610 –15. Petta CA, Faundes A, Dunson TR, Ramos M, DeLucio M, Faundes D, Bahamondes L. Timing of onset of contraceptive effectiveness in Depo-Provera users. II. Effects on ovarian function. Fertil Steril 1998;70: 817–20.
Timing of Onset of Contraceptive Effectiveness in Norplant威 Implant Users II Effect on the Ovarian Function in the First Cycle of Use Vivian Brache,* Paul D. Blumenthal,† Francisco Alvarez,* Thomas R. Dunson,‡ Leila Cochon,* and Anibal Faundes§
The objective of this study was to time the onset of contraceptive effectiveness in Norplant威 implant users, when the capsules were inserted beyond the first 7 days of the cycle, based on the immediate effect on the ovarian activity. A total of 42 healthy women requesting Norplant implant contraception were enrolled at clinics in Santo Domingo, Dominican Republic, and in Baltimore, Maryland. Implants were inserted on days 8 –13 of the menstrual cycle. Blood samples for estradiol (E2), progesterone ( P), luteinizing hormone (LH) (in a subset of 12 women), and levonogestrel (LNG) assay, were taken at 0 h and at 6, 12, 24, 72, and 168 h postinsertion. Ovulation, as defined by P ⬎2.5 ng/mL, occurred in 40% of subjects. A short lasting, frequently blunted, LH peak occurred within 12 h postinsertion, in all these subjects. The remaining subjects had anovulatory cycles with two distinct E2 profiles: continuously increasing E2 levels to a high mean of 414.3 pg/mL (28%), or no sustained increase in E2 (32%). Most cycles (86%) in which Norplant was inserted with high E2 levels (⬎175 pg/mL) were ovulatory, whereas none were ovulatory with low E2 (⬍100 pg/mL) at insertion. Based on the endocrine effects of Norplant implant insertion in the midadvanced follicular phase, in which ovulation will either occur within 48 h of insertion or will be impaired, additional contraceptive protection is necessary only for 3 days. CONTRACEPTION 1999;59:245–251 © 1999 Elsevier Science Inc. All rights reserved. KEY WORDS:
Norplant威, back-up contraception, ovulation inhibition, luteinizing hormone peak
*PROFAMILA, Santo Domingo, Dominican Republic; †Johns Hopkins Bayview Medical Center, Baltimore, Maryland; ‡Family Health International, Research Triangle Park, North Carolina; and §Centro de Pesquisas de Doenc¸as MaternoInfantis de Campinas (CEMICAMP), Campinas, Sao Paulo, Brasil Name and address for correspondence: Vivian Brache, Biomedical Research Department, PROFAMILIA, P.O. Box 1053, Santo Domingo, Dominican Republic. Submitted for publication February 23, 1999 Revised April 15, 1999 Accepted for publication April 15, 1999
© 1999 Elsevier Science Inc. All rights reserved. 655 Avenue of the Americas, New York, NY 10010
Introduction The contraceptive efficacy and acceptability of Norplant威 subdermal implants have been extensively documented.1,2 Several studies have shown that the main mechanisms of action of this progestin-only, long acting method are ovulation inhibition or dysfunction and deleterious effects on cervical mucus rendering sperm penetration difficult.3–12 However, the majority of these studies have been conducted during long-term use. Initial studies showed that, when the implants are inserted in the first 7 days of the cycle, ovulation inhibition is achieved in the first cycle.13,14 However, limiting insertion to the first 7 days of the cycle may hinder the woman’s access to adequate contraception; therefore, current clinical guidelines state that implants may be inserted at any time in the cycle, provided that there is reasonable assurance that the woman is not pregnant and that a back-up method is used for the first week.15,16 To better define the length of time that backup contraception would be needed when inserting Norplant implants beyond the first 7 days of the menstrual cycle, we undertook this clinical study, which was designed to time the onset of contraceptive effectiveness in Norplant implant users when inserted in the midadvanced follicular phase (days 8 –13 of the cycle). The outcome measures of interest were indicators of ovulation inhibition in the same cycle of use and changes in cervical mucus in the first week of use. The first report in this series, which examined the effect on cervical mucus in the first hours to days postinsertion, has recently been published.17 This report is the second in this series and focuses on the effect of levonorgestrel over the ovarian function in the first cycle postinsertion. ISSN 0010-7824/99/$20.00 PII S0010-7824(99)00028-1
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Materials and Methods Study Information The methods, study design, schedule of visits, and subject characteristics have been previously described.16 Briefly, this study was designed as a prospective, descriptive investigation with the objective to obtain scientific data on the changes in cervical mucus and key hormones within the first hours to days after Norplant implant insertion, and to better estimate when the cervical and hormonal environments were hostile enough to suggest impaired fertility. A total of 42 women who were between days 8 and 13 of their menstrual cycle and who had requested Norplant implants were admitted to the study at two reproductive health clinics: one in Santo Domingo, Dominican Republic, and the other in Baltimore, Maryland. Volunteers had to be abstinent or use nonspermicidal condoms for the duration of the study. Subjects made up to five follow-up visits postinsertion (6, 12, and 24 h postinsertion, and days 3 and 7 postinsertion). Cervical mucus and blood samples were obtained with the primary outcome measures being cervical mucus scores, sperm penetration distances, and serum levels of progesterone (P), estradiol (E2), and levonorgestrel (LNG). Estradiol and progesterone were assayed in samples taken before insertion (hour 0) and on days 1, 3, and 7 postinsertion. Two subjects (both in day 13 of the cycle) had baseline progesterone levels above 2.5 ng/mL (3.6 and 21.2 ng/mL), indicative of prior ovulation, and were therefore excluded from this analysis. Levonorgestrel was assayed in the blood samples taken at each visit. LH was assayed only in the 12 women at the Santo Domingo clinic who showed increase in P levels indicative of luteal activity (P ⬎2.5 ng/mL). Progesterone levels ⬎2.5 ng/mL was used as an indicator of ovulation, considering that the sampling period was short (7 days) and did not cover the entire luteal phase.
Hormone Assays Samples from both centers were shipped to the Steroid Research Laboratory in Helsinki, Finland for central analysis of E2, P, and LNG. Estradiol was determined by radioimmunoassay according to the protocol from the World Health Organization, with an intraassay coefficient of variation (CV) of 5.0%– 7.3% and an interassay CV of 10.4%–16.6%. Progesterone was determined by a time resolved solid phase fluoroimmunoassay (Delfia, Wallac Oy Pharmacia, Turku, Finland) with an intra- and interassay CV of 3.3%–7.3% and 2.7%–10.1%, respectively. Levonorgestrel was measured by radioimmunoassay with tri-
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tium labeled levonorgestrel as tracer, as described by Weiner and Johansson.13 The intra- and interassay CV varied from 2.3% to 6.3% and from 7.9% to 12.0%, respectively. LH was determined locally at the laboratory of the Department of Biomedical Research of PROFAMILIA in Santo Domingo by an enzyme immunoassay (EIA) provided by the World Health Organization Matched Reagent Programme (Geneva, Switzerland) standardized against International Reference Preparation 80/552 and with an intra- and interassay CV of 2.4% and 9.4%, respectively. The 2 test was used to test whether there was an association between estradiol levels at the moment of insertion and subsequent ovarian profile.
Results The 40 subjects enrolled ranged in age from 18 to 33 years, with a mean of 23.8 years. Their average weight was 57.9 kg, with a range of 40.0 – 83.6 kg. Of the insertions, 15% were done on day 8/9 (n ⫽ 6), 32% on day 10/11 (n ⫽ 13), and 53% on day 12/13 (n ⫽ 21). Upon evaluation of the hormonal results, three distinct ovarian profiles were observed after Norplant implants insertion. Two of these profiles were anovulatory (P ⬍2.5 ng/mL): profile A was characterized by no sustained postinsertion increase in E2 levels, whereas profile B was characterized by a continuous rise in E2 (⬎250 pg/mL). The third profile (profile C), was defined as having “luteal activity”; in these subjects, progesterone levels rose to ⱖ2.5 ng/mL and the majority most likely corresponded to ovulations. Of the 40 women enrolled, profile A was observed in 13 women (32%) and profile B in 11 (28%), whereas luteal activity (profile C) was observed in 16 (40%). Subjects with profile A had the lowest preinsertion mean E2 (82.2 ⫾ 17.1 pg/mL), with no sustained postinsertion increase in serum levels, as shown by a mean of 85 pg/mL on day 7 postinsertion. Mean P levels in this group, remained ⬍0.5 ng/mL throughout the study (Figure 1). Subjects with profile B had a mean E2 level of 132.5 ⫾ 42.1 pg/mL at insertion and exhibited a continuous and pronounced rise, reaching a mean of 414.3 pg/mL at Day 7 postinsertion, with a mean P level of 0.7 ng/mL on this same day. Subjects with luteal activity (profile C) had the highest mean estradiol levels before insertion (210.1 ⫾ 71.5 pg/mL), followed by a drop to 191.8 pg/mL and 113.7 pg/mL on day 1 and day 3 postinsertion, respectively. A slight rise to 148.4 pg/mL was observed on day 7. The mean P levels among these 16 subjects with luteal activity reached 2.7 ⫾ 1.6 and 8.5 ⫾ 3.4 ng/mL on day 3 and day 7 postinsertion, respectively. However, four of these subjects had progesterone levels ⬍6 ng/mL at
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Figure 1. Different ovarian profiles observed in first cycle of use after Norplant implant insertion on days 8 –13 of the follicular phase.
day 7, suggestive of luteal insufficiency or luteinized unruptured follicle (LUF). Of the 16 subjects with luteal activity, 12 were from Santo Domingo and four from the Baltimore clinic. LH was measured in all 12 subjects from the Santo Domingo clinic, but additional serum from the Baltimore women was not available for this assay. Two women already had an elevated LH peak at the time of insertion (55.9 and 56.6 IU/L), which decreased to ⬍10 IU/L by 24 h postinsertion. In five other subjects, the onset of the LH surge was probably in progress at insertion, with values between 9.0 and 18.3 IU/L, followed by a short-lived peak that occurred within 12 h (31– 66 IU/L) and that had dropped in all instances by 24 h postinsertion. The five remaining subjects had low LH levels at time 0 (⬍7
IU/L), followed by a small surge also within 12 h (8.0 –19.7 IU/L, 143%– 650% increase from time 0), and returning to baseline levels by 24 h postinsertion. (Table 1). In one of these last cases a second LH elevation was observed on day 3 (14.5 IU/L) that was higher than that seen at 12 h (9 IU/L). If sampling had been taken only every 24 h, no LH surge (⬎20 IU/L) would have been detected in any of the subjects, except in the two women who already had an LH peak at the time of insertion (⬎50 IU/L). Figure 2 shows the percentage of cycles with luteal activity according to the day of cycle in which the insertion was done. No luteal activity was observed among the six women in whom insertions were done before day 10 of the cycle; however, the percentage of cycles with luteal activity ranged between 38% and
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Table 1. LH levels (IU/L) at 0, 6, 12, 24, and 72 h after Norplant implant insertion in women with luteal activity Subject no. 16 10 28 6 4 23 22 2 20 33 27 13
0h
6h
12 h
24 h
72 h
1.4 2.6 3.0 4.1 6.7 9.3 9.4 10.1 14.1 18.3 (55.9) 56.6
4.1 (19.7) (9.0) 11.7 11.4 (38.7) (58.2) 21.8 6.0 (30.7) 14.6 (91.4)
(8.0) 12.8 7.0 (15.0) (16.3) 34.9 35.4 (46.0) (65.7) 19.6 6.0 70.3
5.4 3.5 3.8 4.9 6.2 5.8 7.2 19.9 12.1 7.4 2.6 7.6
6.8 6.0 14.5 5.4 11.3 13.4 10.3 23.3 22.7 7.7 6.2 11.6
LH peaks in parentheses.
60% when implants were inserted between days 10 and 13 of the cycle. Table 2 shows the percentage of women in each profile, according to E2 level at insertion. A very clear correlation was found between estradiol levels at insertion and subsequent ovarian profile: profile A (no sustained increase in E2 and no luteal activity) was observed in 83% of the women with low E2 levels at insertion (⬍100 pg/mL) and in none of those with high E2 levels preinsertion (⬎175 pg/mL). On the other hand, luteal activity occurred in 86% of the cycles in which estradiol levels were ⬎175 pg/mL at the moment of insertion, whereas it did not occur in any woman who had E2 levels ⬍100 pg/mL at insertion (p ⫽ 0.0000). Levonorgestrel levels rapidly attained a mean value
Figure 2. Percentage of cycles with luteal activity according to day of cycle in which Norplant implants were inserted.
above 600 pg/mL at 6 h postinsertion, further increasing to above 900 pg/mL at 24 h, and still remaining near those levels at days 3 and 7 postinsertion (Figure 3). Although significant variability existed between subjects, no significant difference in levonorgestrel levels was observed among the three distinct groups of ovarian profile.
Discussion The data presented here indicate that the effect of the initial administration of levonorgestrel on the menstrual cycle depends on the degree of follicular development existing at the moment of insertion. Our results, when considered with those of previous studies of the endocrine profile and follicular development in women during long-term use of Norplant,8,10,11 suggest the following sequence: if the follicular development is at an early stage, based on low E2 levels (⬍100 pg/mL), the follicular development will be interrupted. When an intermediate degree of development has been attained, the follicle will continue to grow, with increasing high estradiol levels but without subsequent rupture or luteinization. If the follicle has reached preovulatory development, a short-lived LH surge will follow shortly, within the first 12 h of insertion, followed by luteal activity (either LUF or ovulation). Forty percent of the subjects, those who appear to have ovulated after insertion, may have required another form of contraception. All of them had a LH surge within 12 h after insertion. Considering that ovulation occurs around 9 –10 h after the LH peak, with an upper variability of about 24 h,18 –20 and considering that conception is highly unlikely 24 h after ovulation,21 it seems that 3 days of additional protection would be sufficient in women. Furthermore, the normal mean duration of the LH surge is 48 –50 h,22,23 and studies show that a shortlived surge may be incompatible with pregnancy
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Table 2. Percent distribution of women in each ovarian profile stratified by estradiol (E2) (pg/mL) levels at insertion
Ovarian profile after insertion Profile A (no further E2 increase, no luteal activity) Profile B (E2 sustained increase, no luteal activity) Profile C (luteal activity)
E2
Total no. (%)
<100
100–175
>175
13/40 (32%) 11/40 (28%) 16/40 (40%)
10/12 (83%) 2/12 (17%) 0/12 (0%)
3/14 (21%) 7/14 (50%) 4/14 (29%)
0/14 (0%) 2/14 (14%) 12/14 (86%)
p ⫽ 0.0000.
because of the lack of oocyte maturation or inadequate corpus luteum development and function.24,25 This study confirms the observation that levonorgestrel seems to accelerate the appearance of a shortlived, frequently blunted LH peak when sufficient estradiol priming has occurred.26 Other reports have shown the importance of the progestational signal after an E2 increase to induce the LH surge.22,27–29 Evidence exists that the administration of mifepristone in the late follicular phase delays the LH surge by antagonizing the progestational signal.30 –32 Furthermore, in phase I studies testing the contraceptive feasibility of a combination of mifepristone/progestin sequential regimens, the progestin administered after 15 consecutive days of mifepristone use appeared to trigger a pituitary gonadotrophin surge.33,34 In a similarly designed protocol, Petta et al. report on the effect of the injection of 150 mg of depot medroxyprogesterone acetate (DMPA), on days 8 –13 of the cycle, on the ovarian function in the first month of use. Thirty percent of the subjects ovulated, and high E2 levels were also shown to be an indicator
of subsequent follicular rupture. Ovulation only occurred among women who had E2 levels of ⱖ100 pg/mL. Follicular rupture, as documented by ultrasound observations, had occurred in all women by day 3 after DMPA administration. These authors also conclude that DMPA may trigger the ovulatory mechanism.35 In summary, the data here presented suggests that two possible ovulatory dysfunctions with a contraceptive effect follow Norplant implants insertion in the second half of the follicular phase of the cycle: 1) inhibition of ovulation, with or without continued follicle development; or 2) induction of a blunted LH peak in amplitude and duration. This blunted LH peak is characteristically observed among ovulating, long-term Norplant implant users, who are considered to be well protected against pregnancy.7,9,11 On the other hand, if the LH surge is already well underway, a normal LH peak may occur within the 12 h after insertion of the implants. When the latter condition is present, the woman will not be protected against pregnancy for the first 2 or 3 days after implant insertion.
Figure 3. Serum levonorgestrel levels in the first week after insertion of Norplant subdermal implants.
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In conclusion, considering the immediate endocrine effects of Norplant implants when inserted in the midadvanced follicular phase, irrespective of the day of the cycle, additional protection is recommended for 3 days only. This recommendation is further reinforced by the progestagenic changes observed in the cervical mucus and adverse effects on sperm penetration reported in the same group of women within 3 days after Norplant implant insertion.17 This study also demonstrates the immediate contraceptive effect of Norplant implant when implants are inserted within the first 7 days of the cycle, a period in which E2 levels are low, and backup contraception is not required. This window could probably be extended through day 9, inasmuch as ovulations did not occur among six women in which insertions took place on day 8/9. However, because the number of women in this study is small, the burden of an unwanted pregnancy is high, and the inconvenience of 3 days of additional back-up protection is minimal, it seems appropriate to retain the conservative approach of using additional means of protection for 3 days when insertion has been performed beyond the first 7 days of the cycle.
Acknowledgments We acknowledge and are grateful to Irving Sivin for assistance in the statistical analysis and to Laneta Dorflinger and Lucinda Glover for comments on the draft manuscript. Partial support for this work was provided by Family Health International (FHI; Research Triangle Park, North Carolina) with funds from the US Agency of International Development (USAID), although the views expressed in this article do not necessarily reflect those of USAID. FHI is an international nonprofit organization that conducts research and provides technical assistance in reproductive health, family planning, sexually transmitted diseases, and AIDS.
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