Contraceptive vaginal ring--a rising star on the contraceptive horizon

Two studies were carried out at AIIMS to judge efficacy, side-effects and acceptability of the contraceptive vaginal ring, a Silastic ring with an inner core containing 6.0 mg levonorgestrel mixed with Silastic and an outer core of Silastic only. It releases levonorgestrel at a constant rate of 20 micrograms/day and remains effective for 90 days. The first study of 50 women lasted for 12 months and the second study of 46 women lasted 24 months. Menstrual irregularity in 36% of women was the commonest reason for discontinuation. The majority of women experienced menorrhagia or irregular spotting per vaginum. Vaginal irritation or increased vaginal discharge was the second commonest reason for discontinuation and was noted in 23% of subjects. Repeated spontaneous expulsions accounted for discontinuation in 6% of subjects. No method-related failure was noted in the study. Follow-up study revealed users to be happier with the ring than with any other method and no spouse complained of feeling the ring during coitus. With its ease of administration, absence of gastrointestinal side-effects and a high success rate, the contraceptive vaginal ring is a promising contraceptive method for the last decade of the 20th century.

Two-year carbohydrate metabolism studies in women using a norethindrone or levonorgestrel triphasic oral contraceptive

Carbohydrate metabolism was prospectively studied in 28 women using triphasic oral contraceptives (TOC) for two years. They were tested using a 100-gram oral glucose tolerance test with measurements of plasma glucose and insulin levels during the three-hour test. The women were randomly assigned to either a norethindrone-containing TOC or a levonorgestrel-containing TOC. Both types of drugs contained the estrogen ethinyl estradiol. No significant changes were noted in the norethindrone TOC group. The levonorgestrel TOC two-year test had a significant elevation of the 0.5- and 2-hour plasma glucose values and the fasting insulin value. These data show that the two triphasic oral contraceptive preparations affect carbohydrate metabolism differently.

Renal and myocardial adrenoceptors in steroid contraceptive-induced hypertension in rats

1. Systolic blood pressure (SBP), bodyweight, organ weight, renal beta-adrenoceptor and myocardial beta- and myocardial alpha 1-adrenoceptor characteristics were investigated in female Sprague-Dawley rats after chronic subcutaneous (s.c.) administration of ethynyloestradiol (EE2, 0.2 microgram/day), levonorgestrel (NG, 2.0 micrograms/day) separately and in combination (EE2/NG). 2. EE2 caused a sustained increase in SBP from 6 weeks (maximum at 14 weeks, +22 mmHg compared to control) which was accompanied by increased kidney and ventricle weight after 12 weeks. EE2/NG-treated rats also demonstrated a gradual rise in SBP (maximum at 9 weeks, +18 mmHg compared with control) with renal and ventricular hypertrophy, but were normotensive by week 17 of treatment. In contrast, NG induced only transient SBP increases (maxima at 5 and 10 weeks, +14 mmHg compared with control), unaccompanied by organ hypertrophy. Norethisterone (2 micrograms/day) also produced transient increases (weeks 6-8, +13 mmHg) in SBP. 3. alpha 1- and beta-adrenoceptors were investigated using [3H]-prazosin and (-)-[125I]-iodocyanopindolol (ICYP), respectively. Myocardial alpha 1- and beta-adrenoceptors were unaffected by steroid contraceptive administration for up to 12 weeks. Renal beta-adrenoceptor affinity was markedly reduced in 12 week EE2-treated rats (equilibrium dissociation constant, KD, 53 +/- 7 pmol/L) compared with controls (KD, 31 +/- 4 pmol/L), an effect which was prevented by co-administration of NG (KD, 34 +/- 8 pmol/L). Renal beta-adrenoceptor number was not altered by any treatment. 4. The relatively late onset of organ hypertrophy and beta-adrenoceptor changes appear to result from, rather than cause, EE2-induced hypertension.

The effect of low-oestrogen combined pill, progestogen-only pill and medroxyprogesterone acetate on oral glucose tolerance test

The effect of a low-oestrogen combined pill, progestogen-only pill and medroxyprogesterone acetate on oral glucose tolerance test was studied in 29, 30 and 9 indigenous Kenyan women respectively. Glucose tolerance test was performed before treatment was started and then after 1,3 and 6 months in microgynon users. The mean areas under the glucose curves were also significantly elevated. Significant increase in blood glucose values were noted only at 30 minutes after 6 months of use of the progestogen-only oral contraceptive but the mean blood glucose values were higher than in the control after 1,3 and 6 months of use. However, the mean values of the areas under the glucose curves were significantly elevated after 1,3, and 6 months of use. Medroxyprogesterone acetate users showed significantly lower fasting blood glucose values at 60 and 90 minutes after 1 month of use, after which the blood glucose values returned to the pre-treatment values. The mean values of the glucose curve areas showed no significant change. It is concluded that both microgynon and minipill cause relative impairment of glucose tolerance test as early as after 1 month of use. Medroxyprogesterone acetate does not impair oral glucose tolerance for at least the first 6 months of use. The implications of these findings are discussed.

Levonorgestrel-releasing intrauterine device in the treatment of menorrhagia

In 20 women with menorrhagia (greater than 80 ml blood loss per menstrual period) a levonorgestrel-releasing intrauterine device (Lng-IUCD) was inserted. Menstrual blood loss (MBL) was measured in two consecutive cycles before the device was inserted and after 3, 6 and 12 months of use. MBL was significantly reduced after 3 months (86%) and after 12 months the reduction was 97%. There was a significant increase (P less than 0.001) in serum ferritin during the first year of Lng-IUCD use. The Lng-IUCD seems to be an important alternative to oral medication and to hysterectomy in the treatment of menorrhagia.

Relative binding affinity of norgestimate and other progestins for human sex hormone-binding globulin

The relative binding affinity of norgestimate for human sex hormone-binding globulin was compared with that of its metabolites and other progestins by measuring their abilities to displace [3H]testosterone from this carrier protein in vitro. Norgestimate and its 17-deacetylated and 3-keto metabolites did not significantly displace [3H]testosterone from sex hormone-binding globulin at concentrations up to 10,000 nM, whereas gestodene, levonorgestrel, and 3-keto desogestrel displaced [3H]testosterone from sex hormone-binding globulin with IC50 concentrations of 23.1, 53.4, and 91.0 nM, respectively. Since it is believed that a progestin may exert androgenic effects by displacing testosterone from sex hormone-binding globulin, thereby increasing circulating levels of free, active testosterone, these data are consistent with the results of preclinical and clinical studies demonstrating the selective progestational activity of norgestimate.

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.

Multicentred clinical study of the metabolic effect of the monthly injectable contraceptive containing dihydroxyprogesterone acetophenide 150 mg + estradiol enanthate 10 mg

The metabolic effect of the monthly injectable contraceptive containing dihydroxyprogesterone acetophenide (DHPA) 150 mg + estradiol enanthate (EEn) 10 mg was compared to that of other regularly used contraceptive methods (pills containing: ethinylestradiol (EE) 0.050 mg + levonorgestrel (LNG) 0.250 mg, EE 0.030 mg + LNG 0.150 mg; EE 0.030/0.040/0.030 mg + LNG 0.050/0.075/0.0125 mg; norethisterone enanthate (NEE) 200 mg i.m.; non-hormonal methods). Serum triglycerides, HDL/LDL-cholesterol, copper, ceruloplasmin, total and free cortisol, CBG, total and free testosterone and SHBG in chronic users were determined. A total of 237 women took part in this study. Taking users of non-hormonal methods as control, triglyceride levels were higher, and total and free testosterone levels were lower in women using DHPA 150 mg + EEn 10 mg and in those taking contraceptive pills (p less than 0.05 - 0.01). Such modifications were slightly less in the group using the injectable. The effects of DHPA 150 mg + EEn 10 mg on HDL/LDL-cholesterol copper, ceruloplasmin, CBG, total and free cortisol and SHBG were rare or non-existent. Nevertheless, the contraceptive pills (even the low-dose formulations) correlate with modifications of all those variables, which were highly significant in comparison with the injectable (p less than 0.01) and with non-hormonal methods (p less than 0.01); there were no differences between the last two methods. The results suggest that the metabolic effect of DHPA 150 mg + EEn 10 mg is not higher than that of the commonly used oral contraceptives. On the other hand, they do not suggest that the dose contained in this injectable is exaggerated. There is no evidence that it produces accumulation of effects in the organism. These findings should be taken into account when referring to the long-term safety of this injectable.

Pharmacokinetics of gestagens: some problems

Various approaches to studying the pharmacokinetics of gestagens and the factors that influence derivation of the parameters are described with levonorgestrel used as an example. Published studies of the pharmacokinetics of levonorgestrel are reviewed, and new information is presented regarding intra- and intersubject variation. Differences between various formulations of levonorgestrel are apparent when the formulations are compared in the same subjects. There is also a marked difference in the parameters when derived under single-dose or steady-state conditions. The role of sex hormone-binding globulin in the metabolism of levonorgestrel is questioned. Large intra- and inter-subject variations in the parameters exist, and a subject may show a large month-to-month variation when one levonorgestrel formulation is used and smaller variations when another formulation is used. This wide variability in the pharmacokinetic parameters, problems that arise in the derivation and interpretation of the parameters, the biologic significance of most of these parameters, and their lack of correlation with pharmacodynamic responses severely limit the usefulness of pharmacokinetic studies of the gestagens.

Metabolic changes during treatment with two different progestogens

Two triphasic oral contraceptives containing the same amount of ethinyl estradiol in combination with gestodene or levonorgestrel were compared with respect to contraceptive effect, on lipid metabolism and coagulation. Serum concentrations of gestodene, levonorgestrel, ovarian and pituitary hormones, and sex hormone-binding globulin were measured. Thirty-five randomized into two groups receiving either of the preparations. Before treatment and in the third and sixth cycles, blood sample were drawn in the morning while subjects were still in bed to obtain basal conditions. The contraceptive effect and cycle control were good with both preparations, and there were only a few minor side effects. Sex hormone-binding globulin was elevated twofold in the levonorgestrel group and threefold in the gestodene group. The gestodene concentration in serum varied more than the levonorgestrel concentration, but with correction for variations in sex hormone-binding globulin binding, less variability in gestodene and levonorgestrel concentrations were seen. High-density lipoprotein2 cholesterol decreased in the levonorgestrel group but was unchanged in the gestodene group, whereas apolipoprotein A1 increased in the gestodene group but not in the levonorgestrel group. Antithrombin III decreased in the gestodene group but was unchanged in levonorgestrel-treated women. Factor VII increased in both groups but more in the gestodene group. We conclude that gestodene has a positive influence on lipid metabolism, probably because of its lower androgenicity, and a slightly negative influence on coagulation. The latter, however, probably has no clinical relevance.

Effects of three combined oral contraceptive preparations containing desogestrel plus ethinyl estradiol on lipid metabolism in comparison with two levonorgestrel preparations

The effects of three different desogestrel-containing combined oral contraceptive preparations on lipid metabolism were compared with those of two levonorgestrel preparations. The following preparations were studied: (1) monophasic desogestrel (150/30), (2) monophasic desogestrel (150/20, containing 20 micrograms of ethinyl estradiol instead of 30 micrograms of ethinyl estradiol, (3) biphasic desogestrel, (4) monophasic levonorgestrel (150/30), and (5) triphasic levonorgestrel. The effects of these preparations were assessed on high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, apolipoprotein A-I, apolipoprotein B, the ratio of high-density lipoprotein cholesterol to low-density lipoprotein cholesterol, and the ratio of apolipoprotein A-I to apolipoprotein B after 3 months of treatment, and the percentage changes with regard to pretreatment were calculated. The monophasic desogestrel (150/30) and biphasic desogestrel preparations induced higher high-density lipoprotein cholesterol and apolipoprotein A-I levels than did their levonorgestrel-containing counterparts. Low-density lipoprotein cholesterol levels were increased in monophasic levonorgestrel and clearly decreased in the lowest ethinyl estradiol-containing monophasic desogestrel (150/20) and biphasic desogestrel preparations. Apolipoprotein B increased in all preparations. The antiatherogenic indexes (ratios of high-density lipoprotein cholesterol to low-density lipoprotein cholesterol and apolipoprotein A-I to apolipoprotein B were higher for monophasic desogestrel (150/30) and biphasic desogestrel than for comparable levonorgestrel-containing preparations. The differences seen between the desogestrel and levonorgestrel preparations can best be explained by the lower intrinsic androgenicity of 3-keto-desogestrel (active metabolite of desogestrel) than that of levonorgestrel.

[Comparative study of norplant-2 and levonorgestrel-releasing intrauterine devices]

Norplant-2 and Levonorgestrel-releasing IUD were studied in a randomized comparative trial for one year. Each group consisted of 100 healthy women among whom contraceptive efficacy and acceptability were studied. Only one woman with the LNG-IUD got pregnancy during the 12 months of use. Expulsion rate was 3.0 in the LNG-IUD. Removal rate for menstrual problems was 3.0 for both groups. The use-related discontinuation were 4.0 and 10.0 respectively. Irregular bleeding was the major side-effect with the two devices. Menstrual blood loss (MBL) and haemoglobin concentration were measured in thirty women at pre- and post-insertion periods. After the 1st, 6th, 12th month of use in Norplant-2 group, the mean MBL were all less than that of pre-insertion, but the differences were not significant. Among LNG-IUD users, the MBL decreased significantly after one year of use. Haemogloblin concentrations were slightly increased in both groups.

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.

Metabolism of levonorgestrel, norethindrone, and structurally related contraceptive steroids

There is limited information on the metabolism of levonorgestrel, norethindrone and structurally related contraceptive steroids. Both levonorgestrel and norethindrone undergo extensive reduction of the alpha, beta-unsaturated ketone in ring A. Levonorgestrel also undergoes hydroxylation at carbons 2 and 16. The metabolites of both compounds circulate predominantly as sulfates. In urine, levonorgestrel metabolites are found primarily in the glucuronide form, whereas norethindrone metabolites are present in approximately equal amounts as sulfates and glucuronides. Of the progestogens structurally related to norethindrone, norethindrone acetate, ethynodiol diacetate, norethindrone enanthate, and perhaps lynestrenol, undergo rapid hydrolysis and are converted to the parent compound and its metabolites. There is no convincing evidence that norethynodrel is converted to norethindrone. Of the progestogens structurally related to levonorgestrel, it appears that neither desogestrel nor gestodene are transformed to the parent compound. However, there is evidence that norgestimate can be, at least partly, converted to levonorgestrel. Further studies on the metabolism of these progestogens are required before we can understand their mechanism of action.

A model to detect interactions between roxithromycin and oral contraceptives

Twenty-two healthy women participated in a study to determine whether roxithromycin (a new macrolide antibiotic agent) obtunds the activity of a triphasic oral contraceptive. The duration of the study was four menstrual cycles. Medication was given as follows: (1) cycle 1, no medication to demonstrate ovulation; (2) cycle 2, triphasic oral contraceptive daily to suppress ovulation; (3) cycle 3, triphasic oral contraceptive daily plus roxithromycin, 150 mg b.i.d.; and (4) cycle 4, triphasic oral contraceptive daily plus rifampin, 300 mg daily. Sonography of the ovaries was performed on day 13, and serum progesterone was measured on day 21 of each cycle. Elevated progesterone indicated ovulation. The presence of a maturing follicle supported this finding. All volunteers ovulated in the first cycle and no volunteers ovulated in the second and third cycles. However, 11 women ovulated when rifampin and the triphasic oral contraceptive were given concomitantly. The findings suggest there is no reason to believe that roxithromycin interferes with the efficacy of oral contraceptives.

A three-year clinical evaluation of Norplant-2 rods in Singapore

A three-year clinical evaluation of Norplant-2 rods in Singapore shows that no pregnancy occurred during the three years of use. The continuation rate at the end of three years was 74%. Desire for planned pregnancy was the main reason for removal during the three years. The post-removal conception rate in women desiring planned pregnancy was 50.0% at the end of one year. This low rate could be attributed to the four women deciding against a pregnancy after removal. However, despite this apparent reason one needs to monitor the post-removal return of fertility closely in the years to come.

A three-year evaluation of metabolic changes in Singaporean Norplant-2 rod acceptors

In this longitudinal study involving 100 Singaporean women, the effects of Norplant-2 rods on metabolic function were evaluated. With respect to liver function, the results indicate possible hepatocellular dysfunction as evidenced by a significant rise in serum bilirubin and a significant fall in total proteins and globulin during the three years of use. As regards lipid metabolism total triglycerides, cholesterol and LDL cholesterol were significantly decreased as compared to their preinsertion values at the end of three years. The HDL-cholesterol was also significantly decreased during the second and third year of use. Despite this, the HDL-cholesterol/total-cholesterol-HDL-cholesterol remained above 0.200. Thus, though speculative, it still appears to indicate that use of Norplant-2 rods is not directly contributory to cardiovascular risk. The use of Norplant-2 was not associated with any significant effect on carbohydrate metabolism after three years of use.

Pituitary, ovarian and endometrial effects of 300 micrograms norethisterone and 30 micrograms levonorgestrel administered on cycle days 7 to 10

The ovarian, endometrial and pituitary effects of 300 micrograms norethisterone (NET) and 30 micrograms levonorgestrel (L-NOG) administered orally on cycle days 7-10 were investigated in two groups of 10 women each, by daily analysis of plasma estradiol (E2), progesterone (PROG), immunoreactive luteinizing hormone (LH) and follicle stimulating hormone (FSH) in a pretreatment control cycle and during NET or L-NOG administration. Endometrial biopsies were obtained for morphometric analysis on cycle day 11 in the control and treatment cycles. Treatment with 300 micrograms NET resulted in an increase in the area under the E2 peak (p less than 0.05), reduction in the number of subjects with normal progesterone profile (p less than 0.05) and a decrease in the area under the progesterone curve (p less than 0.05). The treatment suppressed the LH peak in 4 subjects and progesterone in 4 subjects. The follicular phase was prolonged in one subject. Norethisterone induced marked subnuclear vacuolation in the endometrium, while the glandular mitoses were decreased during NET treatment. Treatment with 30 micrograms L-NOG resulted in a decrease in subjects with normal progesterone profiles (p less than 0.05) and in the area under the progesterone curve (p less than 0.05). The treatment suppressed the LH peak in 3 subjects and progesterone in 4 women. The follicular phase was prolonged in one subject. L-NOG did not significantly increase the diameter of glands or induce subnuclear vacuolation in the endometrial glands.

A three-year evaluation of hemostatic function in Singaporean Norplant-2 rod acceptors

A longitudinal study of hemostatic function was carried out on 100 Singaporean acceptors using Norplant-2 rods for contraception. The results at the end of three years indicate a possible increased predisposition to thrombosis, as evidenced by significant increases in platelet count and aggregability. The prothrombin time (PT) and activated partial thromboplastin time (APTT) continued to remain shortened at the end of three years of use. There was also a general fall in most of the vitamin K coagulation factors. There is thus still an indication of a possible enhanced potential for hypercoagulation at the end of three years of Norplant-2 rod use.

Acceptance and perceptions of NORPLANT among users in San Francisco, USA

Two hundred and five women participating in a five-year clinical trial of NORPLANT and NORPLANT-2 were interviewed about their contraceptive and reproductive history, sources of information and knowledge of NORPLANT, experiences using the method, and the impressions of friends and family about the method. The most common reasons for trying the implants were dissatisfaction with other methods and perceptions about NORPLANT's ease of use. Forty-one percent of acceptors had anxiety prior to insertion; 49 percent of these feared pain, but only 5 percent said that they actually experienced significant pain. Women also feared implant removal, but their fear did not influence their decision to continue or discontinue use, and 74 percent reported little or no pain at removal. Most of the women were pleased with NORPLANT, although 95 percent reported side effects, with 82 percent reporting changes in menstruation. More than one-half of those women who discontinued reported that they would use the implants again. Seventy-four percent of the current users interviewed said they would like to use the implants in the future. For the women enrolled in the clinical trial, NORPLANT appeared to be a highly acceptable method of contraception, despite the frequent occurrence of bothersome side effects.