Plasma levels of d-norgestrel, estradiol and progesterone during treatment with silastic implants containing d-norgestrel

Extended use of levonorgestrel-releasing intrauterine system (LNG-IUS) 52 mg: A population pharmacokinetic approach to estimate in vivo levonorgestrel release rates and systemic exposure including comparison with two other LNG-IUSs

OBJECTIVE

To characterize performance of levonorgestrel-releasing intrauterine system (LNG-IUS) 52mg (Mirena) over 8 years of use and facilitate comparisons with LNG-IUS 19.5mg and LNG-IUS 13.5mg.

STUDY DESIGN

We estimated in vivo levonorgestrel (LNG) release rates and LNG plasma/serum concentrations for LNG-IUS 52mg up to 8 years of use with a population pharmacokinetic (popPK) approach using data from the Mirena Extension Trial (MET) and earlier clinical trials. We compared these with previously published release rates and exposure data for LNG-IUS 19.5mg and 13.5mg. Our 8-year popPK and release models were developed based on measured plasma/serum LNG and sex hormone-binding globulin concentrations and residual LNG content from removed LNG-IUS 52mg devices.

RESULTS

Model-based estimated LNG release rates for LNG-IUS 52mg decreased from ∼21 µg/d after insertion to ∼7.0 µg/d after 8 years, similar to LNG-IUS 19.5mg after 5 years (7.6 µg/d) and higher than LNG-IUS 13.5mg after 3 years (5.5 µg/d). Model-based estimated and measured plasma/serum LNG concentrations showed satisfactory agreement. Average model-based estimated LNG concentrations after 8 years of LNG-IUS 52mg use (100 ng/L [coefficient of variance 39.9%]) were similar to LNG-IUS 19.5mg after 5 years (84.8 ng/L [39.9%]) and higher than LNG-IUS 13.5mg after 3 years (58.1 ng/L [40.8%]).

CONCLUSIONS

The 8-year release and popPK models provide reliable in vivo LNG release rates and concentration estimates, respectively, facilitating direct comparisons between the 3 studied LNG-IUSs. LNG release rates from LNG-IUS 52mg at 8 years are similar to LNG-IUS 19.5mg at 5 years and higher than LNG-IUS 13.5mg at 3 years.

IMPLICATIONS

Levonorgestrel release from intrauterine system reservoirs declines with duration of use in a predictable way, and in relation to the initial load. As release rates and plasma concentrations of levonorgestrel may influence endometrial and systemic side effects, these data may assist clinical decision-making.

Development, validation and utilization of a highly sensitive LC-MS/MS method for quantification of levonorgestrel released from a subdermal implant in human plasma

Levonorgestrel (LNG) is a synthetic progestin that is available in oral contraceptive tablets, a subdermal implant, and an intrauterine system for contraception. LNG pharmacokinetics are a pivotal determinant of contraceptive efficacy and essential in assessing drug-drug interactions influencing LNG exposure following different routes of LNG administration. A highly sensitive LC-MS/MS method was developed and validated to quantify levonorgestrel in human plasma. Liquid-liquid extraction was utilized with a sample volume of 500 μL to extract levonorgestrel from plasma. Chromatographic separation of LNG was achieved with a Fortis™ C18 (3 μm: 100 mm × 2.1 mm) reverse phase analytical column. The mobile phases consisted of de-ionized water plus 0.1% NH4OH (100:0.1%, v/v) (A), and methanol plus 0.1% NH4OH (100:0.1%, v/v) (B) delivered as a gradient at a flow rate of 400 μL/min. Detection of LNG and internal standard (D-(-)-norgestrel-d7) was achieved using positive polarity mode monitoring at 313.2-245.2 amu and 320.1-251.2 amu, respectively. The assay was linear over the calibration range of 49.6 to 1500 pg/mL. This method was used to quantify plasma LNG released by subdermal implant in support of a drug interaction study among women with HIV receiving efavirenz- or nevirapine-based antiretroviral therapy.

Mirena (Levonorgestrel intrauterine system): a successful novel drug delivery option in contraception

This manuscript serves as a review of Mirena, the levonorgestrel intrauterine system (LNG IUS) as a very successful drug delivery system. The LNG IUS has a very high contraceptive efficacy rate, and low rates of patient discontinuation. In addition to its contraceptive benefits, most users experience a decrease in menstrual bleeding over the 5 years of use. LNG IUS has also been used for management of menorrhagia, dysmenorrhea, adenomyosis, and endometrial hyperplasia in some cases. The LNG IUS provides long term efficacy, high rates of compliance, rapid return to fertility, and minimal adverse effects during use.

Pharmacokinetics of a single oral dose of 1.5-mg levonorgestrel when administered as 750-μg tablets or as 30-μg minipills

We examined the pharmacokinetics of a single dose of 1.5 mg of levonorgestrel when administered orally in two different formulations: two tablets of 0.75 mg or 50 minipills of 30 microg of levonorgestrel. Bioavailability of levonorgestrel with minipills was comparable to that with levonorgestrel tablets. These findings suggest that levonorgestrel-containing minipills can be considered as an alternative to standard levonorgestrel tablets for use in emergency contraception.

The levonorgestrel-releasing intrauterine system (LNG-IUS) in HIV-infected women—effects on bleeding patterns, ovarian function and genital shedding of HIV

BACKGROUND

Safe and effective contraceptives are needed for human immunodeficiency virus (HIV)-infected women. The levonorgestrel-releasing intrauterine system (LNG-IUS) is a highly effective contraceptive with additional health benefits. The objective of this study was to evaluate the effects of the LNG-IUS among HIV-infected women.

METHODS

Twelve systematically managed HIV-infected women were studied prospectively. Following a 2-month run-in period, the subjects had an LNG-IUS inserted and were followed up for 1 year. Patterns of bleeding, blood haemoglobin and CD4-lymphocyte content, plasma HIV RNA, serum levels of LNG, of estradiol (E(2)) and of ferritin and genital shedding of HIV RNA were monitored.

RESULTS

Menstrual bleeding was reduced significantly during the use of the LNG-IUS; this was associated with slight increases in serum haemoglobin and ferritin levels. Serum E(2) concentrations remained in the follicular range in all subjects. Among subjects using antiretroviral medication, the proportion of cervicovaginal lavage specimens with detectable HIV RNA was 10% before and after the insertion of the LNG-IUS.

CONCLUSIONS

The effects of the LNG-IUS on bleeding patterns, body iron stores and ovarian function were similar to those seen in healthy women. Genital shedding of HIV RNA was not affected by the LNG-IUS. These data encourage further studies on the effects of the LNG-IUS on reproductive health among HIV-infected women.

Digitized assessment of mammographic breast density in patients who received low-dose intrauterine levonorgestrel in continuous combination with oral estradiol valerate: a pilot study

OBJECTIVE

To perform a pilot study of the effects on the breast by low-dose intrauterine progestogen combined with estrogen.

DESIGN

A prospective pilot study.

SETTING

University hospital.

PATIENT(S)

Twenty postmenopausal women without any previous breast disorder.

INTERVENTION(S)

Women were treated with a low-dose intrauterine system releasing 20 microg/24 hours of levonorgestrel in continuous combination with 2 mg of oral E2 valerate. The effects on mammographic breast density, breast cell proliferation, and hormonal levels were followed for 18 months.

MAIN OUTCOME MEASURE(S)

Change in mammographic breast density and breast cell proliferation. Correlations with levels of hormones, growth factors, and binding proteins.

RESULT(S)

Three women showed an apparent increase in density. For the remaining 17 women the changes were only a few percent. Digitized assessment of density showed strong correlations with visual classification scales (rs = 0.96-0.97). There was no increase in proliferation as expressed by the percentage of MIB-1-positive breast cells in fine-needle aspiration biopsies. Increase in breast density displayed a positive correlation with patients age (rs = 0.52) and an inverse relationship with levels of E2 (rs = -0.50) and free T (rs = -0.50).

CONCLUSION(S)

Low-dose intrauterine administration progestogen may develop into an attractive alternative for hormonal therapy in postmenopausal women as endometrial protection may be achieved at very low systemic levels.

Pharmacokinetics and endometrial tissue levels of levonorgestrel after administration of a single 1.5-mg dose by the oral and vaginal route

OBJECTIVE

To determine the pharmacokinetics and endometrial tissue levels of levonorgestrel when taken as a single dose of 1.5 mg either orally or vaginally by healthy women in the periovulatory phase of their menstrual cycle.

DESIGN

Prospective randomized study.

SETTING

Academic research institution.

PATIENT(S)

Thirty women with regular cycles allocated to control (n = 5), oral (n = 13), and vaginal (n = 12) groups.

INTERVENTION(S)

Blood samples were drawn before (0 time) and at 0.5, 1, 2, 4, 6, 8, 24, 48, and 168 hours after levonorgestrel administration. Endometrial samples were collected 24 and 168 hours after levonorgestrel administration.

MAIN OUTCOME MEASURE(S)

Plasma and endometrial tissue levels of levonorgestrel.

RESULT(S)

Plasma concentrations of levonorgestrel were significantly greater during the first 48 hours after oral administration. However, 7 days after levonorgestrel administration, the plasma levels were similar for both treatments (3-5 nmol/L). Compared with vaginal administration, oral administration resulted in higher peak plasma concentrations (Cmax 64 vs. 10.7 nmol/L), with a shorter time to reach the maximal concentrations (Tmax 1.4 vs. 6.6 hours) and with a greater AUC (509 vs. 175 nmol/L). Interestingly, the half-life of levonorgestrel was shorter after oral administration (25 hours vs. 32.6 hours). Levonorgestrel tissue concentrations were not related to the plasma levels. Levonorgestrel values tended to be higher in endometrial tissue after vaginal administration. The ratio between plasma and endometrial concentrations of levonorgestrel differed significantly between the groups.

CONCLUSION(S)

These data indicate that orally administered levonorgestrel achieves higher plasma levels sooner than vaginally administered levonorgestrel. However, plasma levels after vaginal administration are more sustained and were likely to be sufficient for ovarian suppression. Therefore, the vaginally administered levonorgestrel could be considered as an alternative option for emergency contraception.

Pharmacokinetic study of different dosing regimens of levonorgestrel for emergency contraception in healthy women

BACKGROUND

Levonorgestrel (LNG) is a commonly used progestin for emergency contraception; however, little is known about its pharmacokinetics and optimal dose for use.

METHODS

Serum levels of LNG and sex hormone-binding globulin (SHBG) were measured in five women who received three different regimens: A: 0.75 mg LNG twice with a 12 h interval; B: 0.75 mg twice with a 24 h interval; and C: 1.50 mg in a single dose, with a washout period of 28 days between each treatment. Blood samples were taken before pill intake and at 1, 2, 4, 8 and 12 h after each dose, every 12 h up to day 4 and every 24 h until day 10. LNG and SHBG were measured in all samples.

RESULTS

Maximum LNG concentrations were of approximately 27 nmol/l for treatments A and B, and close to 40 nmol/l for treatment C. The area under the curve was significantly higher for treatment C during the first 12 h, and significantly lower for treatment B during the first 24 h. After 48 h and up to 9 days from onset of treatment, serum LNG levels were similar in all three regimens. SHBG levels remained stable for 24 h, decreasing to 60% of the initial value from day 5 until day 10, with no difference between regimens.

CONCLUSIONS

The similarity of LNG serum levels obtained with one single dose of 1.5 mg or two doses of 0.75 mg with a 12 h interval justify a clinical comparison of these two regimes.

Levonorgestrel concentrations during 7 years of continuous use of Jadelle contraceptive implants

Serum levonorgestrel concentrations were assayed in a multicenter, 7-year study of 199 users of Jadelle rod implants. We examined drug levels, patterns of changes, factors affecting drug levels, and concentrations at which pregnancies occurred. Mean levonorgestrel concentrations declined from 435 pg/mL at 1 month of use to 64% of that value (280 pg/mL) at the end of 3 years. Between the end of the third and fifth years neither mean nor median serum levels varied markedly. At 5 years the mean concentration was again 64% of the first month's mean. Declining levels were observed thereafter through the end of 7 years when the mean, 224 pg/mL, was 52% of the 1-month value. Last measured drug concentrations of women who became pregnant during Jadelle use had mean and median values of 152 and 144 pg/mL, respectively, and a maximum value of 180 pg/mL. Analyses indicated ponderal index, body weight, duration of use, and a single clinical center were the most important variables affecting measured levonorgestrel levels. Approximately one-third of assays in the sixth and seventh years were found to be below 180 pg/mL, suggesting that Jadelle levonorgestrel implants would not maintain sufficiently high levels of effectiveness against pregnancy after 5 years and that heavier women would then be at greater risk of pregnancy.

Effects of oral contraceptives on breast epithelial proliferation

The association between oral contraceptive (OC) use and breast cancer is not fully understood. Estrogen is a known mitogen to breast epithelial cells, but there is still a controversy about the effect of added progestogens. Fine needle aspiration (FNA) biopsies were used to assess epithelial proliferation in normal breast tissue from 106 healthy premenopausal women with and without oral contraceptives. In 26 women biopsies were performed before and after 2 months of OC use. Proliferation, expressed as percentage of Ki-67/MIB-1 positive cells, was correlated to endogenous progesterone, androgenic/anabolic compounds and exogenous progestogen. We found a higher proliferation (p = 0.03) in OC users compared to non users, with mean values of 4.8% and 2.2%, respectively. There was a positive correlation between proliferation and progesterone levels in non-users and with serum levonorgestrel concentrations in women using OCs containing this progestogen (rs = 0.43, p = 0.02). Women using OCs had significantly lower serum androgen levels compared to naturally cycling women and free testosterone levels displayed an inverse relation to breast epithelial proliferation. There was a marked variation in the response to exogenous sex steroids. In certain women after 2 months of OC use, the percentage of MIB-1 positive cells was as high as 40-50%. The results add to the growing evidence that progestogens may be mitogenic in breast tissue. Increased proliferation during hormonal contraception should be regarded as an unwanted and potentially hazardous side effect. Efforts should be made to define hormonal contraceptive regimens which minimize breast epithelial proliferation and to identify those women with the most pronounced proliferative response.

Timing of onset of contraceptive effectiveness in Norplant implant users. II. Effect on the ovarian function in the first cycle of use

The objective of this study was to time the onset of contraceptive effectiveness in Norplant 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.

Sex hormone binding globulin and free levonorgestrel index in the first week after insertion of Norplant implants

Levonorgestrel has an inhibitory effect on sex hormone binding globulin (SHBG). This decrease in SHBG leads to an increase in the free levonorgestrel index (FLI), which has a stronger biological effect. The interaction between serum levels of levonorgestrel and SHBG in long-term users of Norplant implants has been described. This study was designed to understand the same interaction immediately after the insertion of the implants, in a group of 16 women, sampled at 0 and 6 h and at 1, 3, and 7 days after Norplant implant insertion. Peak serum levonorgestrel levels were achieved at 24 h after insertion, remaining stable on day 3 and decreasing by > 10% by day 7. SHBG did not change during the first 24 h, but decreased by 19% and 60% on days 3 and 7, respectively. FLI more than doubled from day 1 to day 7 after insertion. The large decrease in SHBG and doubling of FLI is not followed by a similar reduction in levonorgestrel, which is hard to explain without an increase in the release rate of the steroid from the capsule.

First week drug concentrations in women with levonorgestrel rod or Norplant capsule implants

Forty-two healthy women volunteered to have blood samples drawn at 2, 4, 8, 24, 48, and 168 h (7 days) following placement of levonorgestrel-releasing rod (LNG rod) or of Norplant capsule implants to permit measurement of drug concentrations. Three clinics recruited 10 women each, half of whom used each type of implant. Twelve additional subjects were later enrolled at one site to provide greater detail for the capsule implants. Throughout the week, women with Norplant implants had apparently higher mean drug concentrations than did women with LNG rod implants, but the differences were significant only in the first 48 h after placement (p < 0.05). Maximum levels for capsule implants were found at the 24-h sample (mean, 1358 to 1474 pg/mL) and for the LNG rod implants at 48 h (772 pg/mL). Body weight was negatively correlated with levonorgestrel concentrations at all times (p < 0.05). For several sampling times, differences between clinics in mean concentrations were statistically significant after weight adjustment. Despite differences by implant type, weight, or clinic location, drug concentrations compatible with contraceptive effect were attained within 24 h in users of LNG rod or of Norplant implants, insofar as all women had levonorgestrel concentrations above 250 pg/mL at the 24-h sample.

Levonorgestrel concentrations during use of levonorgestrel rod (LNG ROD) implants

In a three-year randomized trial that included 398 women, blood samples were collected for the purpose of assaying levonorgestrel concentrations in women using a new two-rod contraceptive implant system or an earlier implant formulation, Norplant-2 implants. Sample collection was at 1, 3, 6, 9, and 12 months after placement and semiannually thereafter through three years. Resulting assays and analyses showed that levonorgestrel concentrations of each implant formulation decreased significantly with time after placement, with increasing body weight, and with ponderal index. In the third year, several measures indicated that concentrations of the contraceptive drug were higher in women using the LNG ROD implants than in users of the original formulation. No pregnancies occurred among women in either group in the three years. This study provides evidence that the minimum levonorgestrel concentration needed to protect against pregnancy is below 200 pg/ml, and possibly is below 175 pg/ml.

An enzyme immunoassay for serum and urinary levonorgestrel in human and non-human primates

A microtiter plate enzyme immunoassay (EIA) is reported for the measurement of levonorgestrel (LNG) in serum and urine samples of human and non-human primates, and the results are compared to data obtained by radioimmunoassay (RIA). Rabbit polyclonal antibodies were raised against the bovine serum albumin conjugate of the 3-O-carboxymethyl oxime (CMO) derivative of LNG. The enzyme label was produced by the conjugation of horseradish peroxidase to LNG at the 3-position by the same CMO bridge used for the immunogen. The assay requires 2.5 hours to perform using 2.2-azino-di-(3-ethylbenzthiazoline sulfonic acid) diammonium salt as the chromogenic substrate. Serum (100 microliters) is extracted with petroleum ether prior to assay, whereas urine samples (25 microliters) are diluted and measured directly. The sensitivity of the assay is 0.25 pg/well with a 50% displacement of label at 7.5-9.5 pg and a linear response through 250 pg/well. Minimum levels of 8.7 and 10.0 pg/ml can be detected in serum and urine samples, respectively. Changes in serum LNG concentrations were measured in women and non-human primates following LNG implantation or injection. In the non-human primate study, serum LNG concentrations began to rise rapidly following i.m. injection of LNG, with peak levels occurring on days 3 to 5, then decreasing to approximately 25-35% of peak levels for the duration of the study. Circulating concentrations of 1.86 +/- 0.18 ng/ml LNG were reached in women the first week post-insertion of Norplant implants and decreased by 50% at 7-10 days, 75% after 14-21 days, followed by a steady decrease during the next 60-70 days to constant low levels that exhibited a high individual variation. Correlation coefficients of EIA and RIA results were 0.988 for human serum, 0.926 for human urine, and 0.972 for non-human primate serum.

Androgen levels in women using a single implant of nomegestrol acetate

This study was undertaken to evaluate the effects of a single implant containing nomegestrol acetate (Uniplant) on plasma levels of sex hormone-binding globulin (SHBG), testosterone, free testosterone, androstenedione and on blood pressure, body weight, and the development of acne vulgaris. Plasma levels of sex hormone-binding globulin, testosterone, free testosterone and androstenedione were measured. Blood pressure and body weight were determined. The development of acne vulgaris was evaluated. Total testosterone and androstenedione decreased significantly during two years of Uniplant use but all levels were within the normal range. There were no significant differences in sex hormone-binding globulin and free testosterone during 24 months of Uniplant use. All changes observed in this study were within normal range. SHBG was not affected by Uniplant use. No significant increase in androgen levels and in the development of acne vulgaris was observed in these women using nomegestrol acetate implant during two years. Based on these results, it is possible to conclude that Uniplant had no androgenic effect in women during this study.

Ovarian function after seven years' use of a levonorgestrel IUD

Fifteen women with regular menstrual periods and seven amenorrheic women who had been using a levonorgestrel-releasing (LNg) IUD for more than seven years were studied. For controls, eight women using TCu380Ag IUDs for more than seven years were studied during two complete menstrual cycles. Ovarian function was assessed with hormonal determination and ultrasound examinations. The regularly menstruating women were studied for two complete menstrual cycles and the amenorrheic women for eight weeks. In the regularly menstruating LNg-IUD users, according to progesterone levels, 93% of the cycles were ovulatory but just 58% of these 'ovulatory' cycles showed normal follicular growth and rupture. Follicular cysts and luteinization of regressing follicles were observed in 42% of the 26 'ovulatory' cycles studied. SHBG capacity was decreased in the LNg-IUD users compared with the TCu380Ag users. Progesterone levels were lower in the LNg-IUD users compared with the TCu380Ag users but this difference was not statistically significant. Preovulatory estradiol and LH levels were lower in the LNg-IUD users than in the TCu380Ag users. These differences were not statistically significant. For the amenorrheic women, five had follicular cysts that disappeared spontaneously within 45 days. Two women showed follicular development and rupture. The presence of good cervical mucus was observed in 69% of the ovulatory cycles studied in the LNg-IUD users. This indicates that effects on cervical mucus cannot be the main mechanism of action of the LNg-IUDs. It is concluded that LNg-IUDs may exert a contraceptive effect in many different ways, such as inhibition of ovulation, endometrial changes preventing implantation, alteration of physical and chemical properties of cervical mucus affecting sperm transport and subtle disturbances in hypothalamic pituitary ovarian function, resulting in alterations of follicular development and rupture.

Intrauterine and subdermal progestin administration in postmenopausal hormone replacement therapy

OBJECTIVE

To compare the effects of intrauterine and subdermal administration of levonorgestrel on control of bleeding and on the endometrium in postmenopausal hormone replacement therapy.

INTERVENTIONS

Nineteen women started continuous oral E2 valerate therapy (2 mg daily) together with continuous parenteral progestin therapy. The subjects randomly received either a subdermal levonorgestrel-releasing implant (n = 9) or an intrauterine device (IUD) releasing levonorgestrel (n = 10).

MAIN OUTCOME MEASURES

Serum concentrations of estrone, E2, FSH, sex hormone-binding globulin (SHBG) and levonorgestrel were followed. Endometrial biopsies and transvaginal ultrasonography were used to evaluate the endometrium. The subjects kept daily records of bleeding. The observation time was 1 year.

RESULTS

Serum concentrations of the hormones mentioned above and SHBG were similar in both groups during the observation time, but the patterns of bleeding differed. In the IUD group there were 0.9 days (mean, range 0 to 4 days) of spotting and no days of bleeding during the last month of the follow-up year. In the implant group there were 8 days (mean, range 0 to 25 days) of spotting and 3.4 days (mean, range 0 to 14 days) of bleeding. In histological examination there was uniform atrophy in the endometrial samples from the IUD group, and a weak or absent progestin effect in the implant group.

CONCLUSIONS

In spite of similar serum levonorgestrel concentrations, local intrauterine administration of levonorgestrel resulted in better control of bleeding and in more effective endometrial suppression than subdermal administration.

Studies on a vaginal ring releasing levonorgestrel at an initial rate of 27 micrograms/24 h when used alone or in combination with transdermal systems releasing estradiol

Vaginal rings releasing levonorgestrel (L-NOG) at an initial rate of 27 micrograms/24h were studied in a group of 24 normally menstruating women during three months (i.e., during three four-week segments). Each segment consisted of three weeks with the vaginal rings in situ followed by a treatment-free period of one week. The women were divided into three groups (8 subjects each). The first group received vaginal rings only, the second and third groups were treated, in addition, with transdermal systems (patches) releasing estradiol at a rate of 50 and 100 micrograms/24h, respectively. Peripheral blood samples were withdrawn three times weekly (Monday, Wednesday and Friday) during a pretreatment cycle and during the following three months of treatment. The levels of L-NOG, estradiol and progesterone were analyzed by radioimmunoassay techniques. In all subjects, endometrial biopsies were taken in a control cycle and during the last days with vaginal rings in situ in segments II and III. The treatment with estradiol did not significantly influence L-NOG levels. Considerable differences in the L-NOG levels between the subjects of the same group were observed. Fluctuation in ovarian reaction within groups was also large. Nevertheless, estradiol noticeably increased the proportion of anovulatory cycles; the total number of anovulatory segments was 5, 9 and 19 (out of 24) in the groups "No estradiol", "50 micrograms/24h estradiol" and "100 micrograms/24h estradiol", respectively. A morphometric study of the endometrium indicated a significant decrease in the diameter of glands. This change was due to L-NOG alone, but it seemed to be accentuated by the exogenous estradiol. The occurrence of glandular mitoses increased in both groups receiving estradiol in a dose-dependent manner, indicating an increased endometrial proliferation. The treatment with estradiol did not significantly alter the bleeding pattern.

Sonographic assessment of ovarian and endometrial changes during long-term Norplant use and their correlation with hormonal levels

OBJECTIVE

To study the probability of ovulation and subclinical abortion during long-term use of Norplant and to assess the concomitant endometrial development.

DESIGN

This was a prospective nonrandomized comparative study. The ovaries and endometrium were assessed daily by ultrasonography during 59 menstrual cycles in 50 women who were using Norplant for > 1 year. Serum concentrations of E2, P, FSH, LH, pregnancy specific beta 1 glycoprotein (Sp1), and hCG were also daily measured. The findings were compared with those in 35 ovulatory cycles in normal fertile women not using contraception.

SETTING

Clients of the Family Planning Clinic of Assiut University Hospital (Norplant users) and the hospital women staff (controls).

RESULTS

Sonographic and hormonal evidence of ovulation were observed in one third of Norplant users; two of them resulted in conception. However, the majority of these ovulatory cycles showed low midcycle peaks of E2, FSH, and LH and evidence of luteal phase defect (LPD). Excessive follicular enlargement was observed in 46% of the cycles. Norplant users had significantly thinner endometrium that did not exhibit the normal phasic changes in sonographic texture. Apart from conceptive cycles, no rise in Sp1 or hCG was observed.

CONCLUSIONS

Norplant acts mainly by inhibiting ovulation, but when this occurs, it is associated with LPD and subnormal endometrial development. Subclinical abortion does not contribute to the contraceptive effect.

NORPLANT: levonorgestrel-releasing contraceptive implant

NORPLANT is the newest contraceptive system to be introduced world-wide, with nearly a million current users. It consists of six Silastic capsules containing levonorgestrel (LNg), which are inserted under the skin in the arm. Release of the steroid commences immediately so that, after several weeks, circulating levels of LNg stabilize between 0.3 and 0.4 ng/ml of plasma, and they persist elevated with a minor decline for over 5 years. The gross cumulative pregnancy rate at 5 years is 2.6 per 100 woman-years. In the majority of women it produces no abnormalities in a variety of clinical chemistry, metabolic, haematological and coagulation parameters. The most common side-effect is disruption of the menstrual bleeding pattern; this is reported by two-thirds of the users in the first months and by one-third by the fifth year. Because it is the most disturbing side-effect for many users, counselling prior to insertion is of paramount importance. NORPLANT exerts varying degrees of gonadotrophin and ovarian inhibition, including anovulation and luteal insufficiency. Endometrial development is irregular and, irrespective of oestrogen levels, cervical mucus is thick and scanty at all times due to the strong antioestrogenic effect of LNg. Inhibition of sperm penetration fully accounts for the antifertility effect of NORPLANT in ovulatory cycles. The high contraceptive efficacy, lack of serious side-effects, reversibility and the convenience of long-term unattended use explain the high acceptability of NORPLANT.

A Latin American experience with levonorgestrel IUD

The intrauterine contraceptive device is an effective, safe and convenient contraceptive method. Its use in less developed countries has been limited by the increase in menstrual blood loss, an important issue in populations with a high prevalence of anaemia. The levonorgestrel releasing IUD (LNg IUD) is the first device which is at the same time highly effective, long-lasting and reduces the blood loss during menstruation. This device was tested in 200 volunteers in Santo Domingo, Dominican Republic and in 381 in Campinas, Brazil. The cumulative pregnancy rate was 0 up to 7 years of use. The reduced bleeding was confirmed, and ferritin concentration among long-term users of the LNg IUD was significantly higher than among copper IUD users and controls using no contraception. Mean levonorgestrel plasma levels remained above 100 pg/ml until the seventh year of use. Endometrial histology showed mainly a marked reduction in epithelial growth, with variable signs of decidualization of the stroma. The most important reason for discontinuation in the two centres was amenorrhea, with cumulative rates of 10 and 15, respectively. This device should be very well accepted and will have a clear niche among reversible contraceptives, when available.

Return to fertility after removal of a levonorgestrel-releasing intrauterine device and Nova-T

In a European randomized multicenter study, the efficacy and safety of an intrauterine contraceptive device releasing 20 microgram levonorgestrel/24 hours (LNG-IUD) have been evaluated and compared to the Nova-T. Because the LNG-IUD has a strongly suppressive effect on the endometrium and in some women affects ovarian function, the return to fertility after removal of the IUD was studied. Two-hundred-nine women (71 in the Nova-T and 138 in the LNG-IUD group), who had their IUDs removed because of planning pregnancy, were followed at least 24 months or until termination of pregnancy. For the Nova-T, the cumulative conception gross rate was 71.2/100 women after 12 months (79.7 after 24 months) and for the LNG-IUD 79.1 (86.6 after 24 months). The difference between the devices is not statistically significant, and in spite of the endometrial suppression during use of LNG-IUD, there is no delay of return to fertility and in both groups 96% of the pregnancies occurred during the first year after removal of the device. Eighty-four % of the pregnancies in the Nova-T group and eighty-six % in the LNG-IUD group ended in live births. The results suggest that the endometrium recovers quickly, normal ovulations are established and the fertility seems to be unaffected after use of an LNG-IUD.

Free levonorgestrel index and its relationship with luteal activity during long-term use of Norplant implants

Levonorgestrel serum levels and sex hormone binding globulin (SHBG) were measured in 82 women during different years of use of Norplant implants. The ratio between levonorgestrel and SHBG was calculated as an indicator of the free biologically active fraction of levonorgestrel (free levonorgestrel index, FLI). These parameters were then correlated with the presence of luteal activity, as determined by progesterone levels above 9.6 nmol/L, in a sampling run of 10 samples taken twice a week for five consecutive weeks. Levonorgestrel serum levels remained constant around 1.0 nmol/L during the five-year period. SHBG levels were below normal for the first 18 months of use, returning to normal levels during the last three years of use. The FLI in the first two years was significantly higher than that observed in the later years. The frequency of cycles with luteal activity was 12% during the first 2 years, increasing to 44% in the latter years, when FLI levels were lower. Our results suggest that the changes in SHBG and consequently in the free biologically active fraction of levonorgestrel may largely account for the differences in degree of ovarian suppression observed between the first two years of use of Norplant implants and the latter three, even in the absence of a significant variation in total levonorgestrel concentrations.

Serum nickel, copper and zinc in Norplant users

Changes in serum nickel, copper and zinc were evaluated in 45 Norplant users. Two groups were selected for this study. Group I included 15 regularly menstruating females as controls and as short-term users (90 days after Norplant insertion). Group II included 30 Norplant users for one year or more as long-term users. These elements were determined by atomic absorption spectrophotometry. Serum nickel showed no significant change in short-term nor in long-term users when compared to the control group or to each other. Serum copper and zinc revealed a significant increase in short-term users for a short period of time, which returned to normal levels in long-term users. There was disappearance of the cyclic changes in serum copper and zinc concentrations on comparing their levels in ovulatory to non-ovulatory Norplant users. The use of Norplant has no deleterious effects on serum levels of nickel, copper and zinc.

A review of the effects of long-acting progestogen-only contraceptives on ovarian activity

Progestogen-only contraception acts mainly by blocking cervical mucus and preventing sperm penetration through it does have a variable pattern of contraceptive effects on the endometrium and ovary. In contrast with the complete suppression of ovarian function with combined pill or injectable use, a variable degree of endocrine activity is demonstrated in women choosing a long-acting progestogen-only contraceptive. This degree of suppression of ovarian activity explains the decrease in systemic side-effects, the rapid resumption of ovulation and recovery of fertility following the discontinuation of the method. New delivery systems of progestogens, the vaginal ring and implant, offer better and more consistent contraceptive effects.

Clinical results with subcutaneous implants containing 3-keto desogestrel

Eight healthy women using one Silastic implant of 30 mm length filled with 3-keto desogestrel, the active metabolite of desogestrel, were studied for 36-664 days. The release rate of 3-keto desogestrel was quite constant and around 30 micrograms/day. No ovulations occurred. One woman was amenorrheic, while the others had different bleeding patterns, often with periods of spotting. No other side effects were recorded. The mean plasma levels of 3-keto desogestrel were 0.9 nmol/l after 1 month and 0.5 nmol/l after 12 months. 3-Keto desogestrel was less effective than testosterone, estradiol or levonorgestrel in displacing 3H-dihydrotestosterone from SHBG. It is concluded that contraception with 3-keto desogestrel delivered through an implant is a promising method for further investigation. With a single implant we found a duration of at least one year.

Clinical assessment of treatments for prolonged bleeding in users of Norplant implants

The effectiveness of three drugs in controlling prolonged bleeding in the first year of NORPLANT implants use was tested. The drugs were levonorgestrel (L-Ng, 0.03 mg twice a day for 20 days), ethinylestradiol (EE, 0.05 mg per day for 20 days) and ibuprofen (Ib, 800 mg three times a day for 5 days) and were given orally. A control group received a placebo (PL, one pill of lactose for 20 days). Treatment should start each time a woman experienced eight consecutive days of bleeding or spotting. The 183 volunteers were not aware of the drug administered. A daily record of bleeding and spotting and of treatment intake was maintained. One-hundred-forty women completed the study period; 60 never used the prescribed treatment. Women treated with the three test drugs had significantly fewer bleeding and spotting days during the treated month and also throughout the study year than women using the placebo. The mean number of bleeding plus spotting days per actually treated subject in the first year was 77, 94, 101 and 129 days for the EE, Ib, L-Ng and PL groups, respectively. The administration of EE might help in the management of prolonged bleeding during the first year of NORPLANT implants use.

Ovarian function during use of a levonorgestrel-releasing IUD

Ovarian function was studied for two complete menstrual cycles in 9 regularly menstruating women and for 8 weeks in three amenorrhoeic women who had used levonorgestrel-releasing IUDs (LNG-IUD) for more than four years. Nine patients using copper IUDs (Nova-T) were studied for two complete menstrual cycles as controls. According to progesterone levels, 15/17 cycles in women using LNG-IUDs were ovulatory, whereas only 8/17 cycles showed normal follicular growth and rupture as judged by ultrasound. In ovulatory cycles, the peak progesterone levels were lower than in the controls. The preovulatory estradiol and LH peak levels were also lower than in control subjects. SHBG levels were lower in LNG-IUD users than in copper IUD users. It is concluded that, although the dose of levonorgestrel released from the IUD is very low, it probably exerts an effect on the gonadotrophin secretion, which disturbs follicular development in many of the women studied, which in addition to the local effect on the endometrium, contributes to its high contraceptive efficacy.

Mechanism of action of gestagens

In the mid-1950s it was shown that ovulation can be inhibited by oral administration of progesterone or of synthetic progestogens such as norethynodrel. The idea that progestogens may interfere with fertility even when administered in doses so small, that they do not invariably inhibit ovulation was launched in the mid-1960s by a group of Mexican investigators. Since then a large number of studies have been conducted on the mechanism of action of gestagens when used as contraceptives. The objective of this communication is to review the information collected so far on this topic.

Levonorgestrel-releasing intrauterine device

An intrauterine contraceptive device releasing 20 micrograms levonorgestrel daily has been studied for 15 years. The international clinical experience covers over 8000 woman years. Main characteristics of the levonorgestrel-releasing intrauterine device are its great effectiveness in preventing unplanned pregnancies and a reduction in menstrual bleeding and pain as well as a low infection rate.

Clinical and hormonal effects of two contraceptives: correlation to serum concentrations of levonorgestrel and gestodene

Two triphasic oral contraceptives containing gestodene (GES) (a new progestogen) and levonorgestrel (LNG) were compared with respect to contraceptive effect, cycle control, acceptability and side effects. The serum concentrations of ingested hormones were measured together with ovarian, pituitary, and some adrenal hormones, as well as sex hormone binding globulin (SHBG). The contraceptive effect and cycle control were good with both preparations, and there were only a few minor side effects. SHBG was elevated 2-fold in the LNG group and 3-fold in the GES group. The GES concentration in serum varied more than the LNG concentration, but with correction for variations in SHBG binding, less variability in actual GES and LNG concentrations was seen. Serum levels of FSH, LH, estradiol and progesterone were all depressed with both preparations. The depression was more marked in the GES group, despite lower progestogen ingestion and similar serum concentrations. Equal decreases were found in testosterone, androstenedione and dehydroepiandrosterone sulfate (DHEA-S) with both preparations.

Ovarian endocrine function through five years of continuous treatment with NORPLANT subdermal contraceptive implants

Ovarian endocrine function was assessed in 88 women using NORPLANT subdermal implants during different periods of use and in a control group of 15 women using non-hormonal contraception. Blood samples for estradiol (E2) and progesterone (P) assays were obtained twice a week for five consecutive weeks. Three distinct E2 patterns were observed: one was characterized by fluctuating levels within a normal range (20 to 400 pg/ml), a second pattern corresponded to continuous low E2 levels (below 75 pg/ml in the 10 samples) and the third was characterized by high broad estradiol peaks reaching over 400 pg/ml. The proportion of sampling runs characterized by normal fluctuating levels increased from 38% in the first two years of use to 80% during the fifth year of use. Low E2 profile was only observed during the first two years of use (27%) and in only 1 case at the beginning of the third year of use (5%). The percentage of cycles with high broad estradiol peaks remained between 20-40% without a clear tendency to change in either direction with duration of use. Thirty-three percent of the observed sampling runs had luteal activity (P above 3 ng/ml). The proportion of runs with luteal activity increased from 14% during the first two years of use to 40% during the third and fourth, and 60% during the fifth year of use. All control subjects had luteal activity. The mean highest progesterone level was lower in the NORPLANT runs (8.7 +/- 3.9 ng/ml) as compared to the controls (11.3 +/- 3.8 ng/ml). NORPLANT sampling runs with luteal activity had normal fluctuating E2 levels with only one exception. However, not all cycles with normal E2 levels showed luteal activity. On the other hand, all runs with low E2 levels or high broad E2 peaks were without luteal activity. In summary, women using continuous low-dose levonorgestrel contraception through NORPLANT subdermal implants, have a variable degree of ovarian activity as compared with the more complete depression of ovarian function observed among pill or injectables' users. Ovarian activity becomes closer to normal during the third through fifth year of use.

Effects of treatment with oestradiol/levonorgestrel on bone, lipoproteins and hormone status in postmenopausal women

The aim of the study was to investigate the effects of an oestradiol/levonorgestrel regimen, administered parenterally, on bone metabolism, bone density, lipoprotein metabolism and hormone status. Twenty-five women who had undergone a surgical menopause had an oestradiol/levonorgestrel-containing vaginal ring pessary in situ for 6 months. Within the first month there were sustained changes in the biochemical indices of bone metabolism in keeping with a marked reduction in bone turnover and decrease in bone resorption. Bone mineral content in the distal forearm was measured in 14 patients and a small increase was noted in every patient. Levonorgestrel was well absorbed and the serum levels remained almost constant throughout treatment. There was a gradual increase in serum total oestradiol which became significant at 6 months. Dialysable oestradiol levels rose from 2.6% of total oestradiol at 0 time to 3.3% at 1 month with no further change thereafter. SHBG levels were 23% of pretreatment levels at 6 months. There were sustained decreases in triglyceride, VLDL and HDL cholesterol levels and a transient fall in LDL cholesterol. Total HDL, HDL2 and HDL3 cholesterol levels were reduced by 25, 40 and 21% respectively. The results suggest that levonorgestrel exerts a protective influence on bone either directly or by its effect on the proportion of oestradiol circulating in the free, physiologically active form. The effects on lipoproteins were predominately those of the progestogen component, the lipoprotein risk factors for coronary heart disease being adversely affected.

Norplant: subdermal implant system for long-term contraception

Norplant offers long-term contraception through the use of subdermal capsules filled with levonorgestrel. The six capsules are implanted in the inside part of the upper arm. The levonorgestrel is released from the capsules gradually, providing contraception for about 5 years. The primary mechanism of action of Norplant is suppression of ovulation. Studies have shown a pregnancy rate of 0.6/100 woman-years after 1 year and a cumulative rate of 1.5/100 woman-years at 5 years. Principal side effects are irregular menstrual bleeding and headaches. No changes in carbohydrate metabolism, blood coagulation, or liver function have been reported. Lipid levels have decreased 5% to 15%. After removal of Norplant, fertility returns rapidly, and there have been no adverse effects on infants. Norplant is currently approved in 12 countries; clinical trials are being conducted in 37 countries.

Plasma levonorgestrel levels and ovarian function during the use of a levonorgestrel-releasing intracervical contraceptive device

Levonorgestrel, estradiol and progesterone plasma concentrations were measured over four years of use of a 20 micrograms/day levonorgestrel-releasing intracervical device (LNG-ICD). The mean levonorgestrel concentration showed a slight decline, being 142 + 46 (SD) pg/ml in the third month and 81 +/- 22 pg/ml in the 48th month of LNG-ICD use. However, considerable interindividual variation in levonorgestrel plasma levels between study subjects was observed. In 77% of the monitored cycles, ovulation or a luteinized follicle was observed when judged by a plasma progesterone elevation of over 5 ng/ml. Some follicular function was also noted in anovulatory cycles. Inhibition of ovulatory ovarian function is not the mode of contraceptive action of the LNG-ICD.

Estradiol plasma levels during long-term treatment with Norplant subdermal implants

Estradiol-(E2) plasma levels were assessed in forty-seven women treated for one through seven years with the same set of Norplant implants. Each woman was subjected to one (n = 34), two (n = 11) or three (n = 2) sampling runs. At each sampling run, blood samples were drawn every third or fourth day during 5 or 6 consecutive weeks. Sampling runs were classified as ovulatory (n = 11), anovulatory (n = 49) or uncertain (n = 1) according to progesterone levels. Controls were Copper T users (n = 8), all classified as ovulatory. No significant differences were found for the mean E2 levels between Norplant users and Copper T users and between ovulatory and anovulatory cases. The mean of the peak E2 value found in each sampling run was significantly higher in anovulatory Norplant subjects than in the control group. The mean of the minimum E2 level observed was significantly lower in Norplant cases than in Copper T users. A single woman from the Norplant group and none from the Copper T group had all E2 values below 370 pmol/l. The inhibition of the reproductive function induced by Norplant implants is associated with a wider range of E2 circulating levels. None of the values observed at the extremes should cause serious concerns. High peaks are transitory and opposed by the antiestrogenic effect of levonorgestrel. Persistent low levels which could be associated with a hypoestrogenic state were observed in a single case.

Contraception with NORPLANT implants and NORPLANT-2 implants (two covered rods). Results from a comparative clinical study in Sweden

Two-hundred-and-forty healthy women, ages 18 to 40 years, were randomized in a ratio of 2:5 to use NORPLANT implants or NORPLANT-2 implants. Through three years of use, no pregnancies were recorded among women using NORPLANT implants and two pregnancies were noted among women using NORPLANT-2 implants resulting in a cumulative net pregnancy rate of 1.3 +/- 0.9 per 100 acceptors (mean +/- SE) by the end of year three. This difference was not statistically significant. During the fourth year, no pregnancies were observed in the NORPLANT group, but 4 pregnancies occurred in the NORPLANT-2 group. The most common reason for terminating the study was bleeding disturbances. During the first year there were significantly more terminations due to bleeding problems in the NORPLANT group than in the NORPLANT-2 group. However, during the second year of use the proportion of women discontinuing for bleeding problems dropped considerably among NORPLANT users and during the third year very few women in either group discontinued because of bleeding problems. The continuation rates after one year were for NORPLANT users 59.4% and for NORPLANT-2 users 77.2%. Corresponding figures after three years of use were 46.1% and 51.7%, respectively. The second most common reason for discontinuation was depression and other mood changes. In both groups we noted a slight increase in weight during the study and a slight decrease in blood pressure and hemoglobin levels with time. In conclusion, both NORPLANT and NORPLANT-2 implants are very effective methods for contraception. The efficacy of NORPLANT-2 implants, however, was not acceptable during the fourth year of use in this study. The latter system could, however, become a suitable three-year contraceptive method, possibly with less bleeding disturbances than NORPLANT in the first year.

Recovery of fertility and outcome of planned pregnancies after the removal of Norplant subdermal implants or Copper-T IUDs

The recovery of fertility after discontinuation of NORPLANT implant use was assessed in ninety women who stated a desire for a new child at the time of removal. Three subjects were lost to follow-up after removal. The cumulative probability of conception in the remaining 87 women was 25, 49, 73 and 86 percent at one, three, six and twelve months after removal, respectively. Nine observations were censored either because of the use of a contraceptive method soon after removal of the implants (n = 7) or separation (n = 2). All other cases were pregnant at the end of two years with exception of three subjects where a male factor for infertility was present. There was no significant correlation between the length of NORPLANT use and the length of the interval from removal to conception. A significantly higher frequency of intervals longer than 6 months was observed among women older than 30 years as compared to younger women. Pathology during pregnancy was cholestasia (n = 5), hypertension (n = 1) and gestational diabetes (n = 1). The outcome was term delivery in 59 cases, premature delivery in 4 cases, and spontaneous abortion in 7 cases. One woman is still pregnant and the outcome is unknown in 4 cases. One premature infant died. A contemporary control group of Copper T users enrolled under the same criteria as NORPLANT implant users provided 44 women who had the device removed to become pregnant. The cumulative probability of pregnancy was 27, 69, 84 and 89 at one, three, six and twelve months and all were pregnant by the end of the second year. Six censored observations occurred because of the use of another contraceptive method after removal (n = 3) or loss to follow-up (n = 3). The outcome of pregnancy was term delivery in 23 cases and abortion in 7 cases. Recovery of fertility occurred at a normal rate after NORPLANT implant removal and the incidence of problems detected in the ensuing pregnancy were within the expected range for Chilean women.

Long-term follow-up of women treated with Norplant implants

This report describes the long-term follow-up of 376 women who received NORPLANT implants in the period October 1974 through May 1979. One-hundred-and-ten subjects received replacement implants after variable lengths of use of the first set. The average levonorgestrel plasma levels declined steadily through eight years of use of NORPLANT capsules (r = -.937). Values were 0.35 ng/ml, 0.29 ng/ml and 0.22 ng/ml at treatment years 1, 5 and 8, respectively. Levonorgestrel plasma levels after replacement with a second set of implants were similar to those observed after the first insertion, either when placed in the same site as the first set or in a different area. Nineteen pregnancies occurred during 18,530 woman-months of use of the first set of implants, eleven of them during years 6 through 8 of treatment. The Pearl Index for the first 5 years of NORPLANT implants use was 0.63. No pregnancy has occurred in 4194 woman-months observed during treatment with a second set of capsules. Fifty-six women (14.9%) out of 376 acceptors of the first implant and 10 (9.1%) out of 110 acceptors of the replacement implants were terminated for other medical reasons, mainly bleeding problems and side effects commonly associated with hormonal contraception. Two women died while using NORPLANT implants, one of a cardiac arrest after surgery for a gallbladder disease and one because of endocranial hypertension originating from the rupture of an aneurism of the median cerebral artery. The bleeding pattern observed in the three months after NORPLANT capsules replacement was similar to that observed in the 90 days before replacement and different from that experienced by the same women in the first 90 days of implant use. This finding can be interpreted as an indicator of adaptive changes experienced by the target organs during long-term continuous administration of levonorgestrel. The prompt recovery of fertility after removal of NORPLANT implants suggests that these changes are reversible.

Contraceptive steroids and coronary artery atherosclerosis in cynomolgus macaques

The influence of two types of steroidal contraception on the extent of coronary, aortic, carotid, and iliaco-femoral atherosclerosis was assessed in 57 cynomolgus macaques with moderate diet-induced hyperlipoproteinemia. Thirteen animals were treated with an intravaginal ring that released 17 beta-estradiol and levonorgestrel. Fifteen females were treated with an oral contraceptive (OC) composed of ethinyl estradiol and norgestrel. Fifteen females received placebo vaginal rings, and 14 males were untreated. The contraceptive treatments resulted in similar large reductions in plasma high-density lipoprotein (HDL) cholesterol concentrations. Neither treatment influenced the prevalence of coronary artery atherosclerosis. However, treatment with the contraceptive vaginal ring was associated with increased extent of coronary artery atherosclerosis (plaque size) relative to untreated females, whereas treatment with the OC was not. The contrasting effects of the two treatments could not be explained by differences in total plasma cholesterol, HDL cholesterol, or blood pressure. The results suggest that the greater estrogenic influence associated with the ethinyl estradiol-containing OC resulted in inhibition of coronary artery atherosclerosis despite a pronounced progestin-induced lowering of plasma HDL cholesterol concentration and, further, that hormonal balance may have a marked influence on the relationship between plasma lipids and atherogenesis.

Plasma levels of cortisol and corticosteroid binding globulin during use of Norplant-2 implants

Plasma levels of cortisol and corticosteroid binding globulin (CBG) were studied during one year in eleven healthy women using NORPLANT-2 implants. NORPLANT-2 implants release approximately 50 ug of levonorgestrel/day. A significant diurnal variation of cortisol levels was found during the study. No significant change in cortisol levels compared to pretreatment levels was found. Levels of CBG showed no diurnal variation, but decreased significantly during use of the implants. This was most probably due to a direct effect of the levonorgestrel, as the levels of estradiol did not change compared to pretreatment levels, except for the values after 6 months that were significantly lower than pretreatment levels. A "free cortisol index" calculated as: level of cortisol/level of CBG, was unchanged during treatment compared to pretreatment levels. It is concluded that although CBG levels were reduced, no significant change in cortisol patterns was seen during use of the implants.

Plasma levels of levonorgestrel and free levonorgestrel index in women using NORPLANT implants or two covered rods (NORPLANT-2)

Plasma levels of levonorgestrel, sex hormone binding globulin (SHBG) and estradiol were studied during four years in 283 healthy women using either NORPLANT implants or two covered rods (NORPLANT-2). The women were randomized to use either type of implant. Both implant systems have previously been shown to have similar release rates of levonorgestrel. In both groups plasma levels of levonorgestrel decreased throughout the study, and there were no statistically significant differences between the two groups in mean plasma levels of levonorgestrel. During the study 8 women became pregnant. All pregnancies but one occurred after 35 months of implant use and only in women using the covered rods. No significant differences were seen between the women who became pregnant and the rest of the group using two covered rods with respect to plasma levels of levonorgestrel. SHBG capacity tended to be somewhat higher in women using the two covered rods. As levonorgestrel is to a great extent bound to SHBG, and in that form not biologically active, a "free levonorgestrel index" was calculated as a ratio between levonorgestrel and SHBG. This index was significantly lower in users of two covered rods than in users of NORPLANT implants at 1, 12 and 48 months of use. Women who became pregnant had significantly lower "free levonorgestrel index" than had the rest of the group. It is postulated that the difference in "free levonorgestrel index" between users of the two implant systems reflect differences in release rate, the covered rods having a lower release rate of levonorgestrel than NORPLANT throughout the observation period. It is concluded that "free levonorgestrel index" is a better parameter than levonorgestrel plasma levels to describe implant function, and to discriminate women who are at risk of pregnancy.

Ovulation detection following removal of levonorgestrel subdermal contraceptive implants

The time to resumption of ovulation following the discontinuation of levonorgestrel subdermal implants (Norplant) was assessed in 10 women. A blood sample (2 ml) was taken at the time of Norplant removal and then twice weekly until the first evidence of ovulation (serum progesterone concentration greater than or equal to 5 ng/ml) was documented. Ovulation was resumed in 80% of the cases by 3 weeks and in all the cases by 7 weeks. Prompt return of ovulation following Norplant removal is an additional advantage of this mode of long-acting contraception.

Androgen levels in women using Norplant implants

Plasma concentrations of sex hormone binding globulin (SHBG), testosterone, free testosterone, androstenedione (A4) and levonorgestrel were studied in 17 women before and during use of two levonorgestrel covered rods resulting in identical plasma concentrations of levonorgestrel as Norplant implants. There was a highly significant decrease in SHBG during treatment. Total testosterone and A4 also decreased significantly. Free testosterone remained unchanged. Diurnal variations were found to occur for A4, total and free testosterone, but not for SHBG or levonorgestrel. Moreover, plasma concentrations of testosterone, free testosterone, levonorgestrel and SHBG were measured in a second group of 88 women participating in a clinical study on Norplant implants, who at the one year follow-up visit either denied or claimed to have developed increased facial acne during treatment. There was no difference regarding SHBG, total testosterone, free testosterone or levonorgestrel between the groups of women with and without facial acne. However, the women in the group noticing increased acne during treatment, reported significantly more often to have had acne before treatment compared to the women who did not notice increased acne during treatment. It is concluded that treatment with Norplant implants does not result in increasing plasma levels of androgens.

Levonorgestrel concentrations in maternal and infant serum during use of subdermal levonorgestrel contraceptive implants, Norplant, by nursing mothers

The transfer of levonorgestrel to infants was studied in 42 lactating women in whom the contraceptive subdermal implants, Norplant, were inserted 30 to 40 days postpartum. The women breastfed their infants for one year. Simultaneous mother and infant blood samples were taken once during the year. The levonorgestrel serum concentrations were measured by radioimmunoassay. During the first postinsertion month, the levonorgestrel concentration in the infants serum amounted, on the average, to 5% of the maternal concentration. Thereafter, the ratio ranged from 8 to 13%. The implications of this finding are discussed.

Enhanced metabolism of levonorgestrel during phenytoin treatment in a woman with Norplant implants

A 26-year-old woman, treated with phenytoin for 10 years because of epilepsy, had Norplant subdermal implants inserted after a legal abortion. She became pregnant again after nine months of Norplant use. Her plasma levonorgestrel (LNG) levels were followed during one month during phenytoin treatment and then later during one month after discontinuation of phenytoin. During phenytoin treatment, plasma LNG levels were markedly below the levels found in healthy women with Norplant. There was a pronounced, statistically significant increase in plasma LNG levels after discontinuation of phenytoin. The plasma levels of sex hormone binding globulin were markedly above those found in normal healthy women during treatment with phenytoin and decreased significantly after cessation of phenytoin. The effects on the pharmacokinetics of LNG were reflected by effects on the menstrual cycle. During phenytoin treatment, the woman had regular ovulatory menstrual cycles. After cessation of phenytoin, her cycles became irregular and during the study period of one month, no signs of ovulation were found. It is concluded that treatment with phenytoin during use of Norplant subdermal implants enhances the metabolism of LNG to an extent where the contraceptive efficacy is endangered.