Production of cervical mucus in ewes treated with exogenous progestagen and oestrogen

The production of cervical mucus was measured at intervals of 6 hr about the onset of oestrus in ewes treated with exogenous progestagen administered by the intramuscular or intravaginal route. There was a quadratic pattern of production with peak values early in the oestrous period. Although there were no differences between groups in the total amount of mucus produced, levels recorded in untreated ewes were lower in the pre-oestrous period. Within the intravaginal progestagen group, those ewes which exhibited oestrus within 42 hr of sponge withdrawal produced greater quantities of cervical mucus than did animals which came into heat after this time. This relationship was not evident within the intramuscular progesterone group. It was concluded that the variable cervical mucus response observed after the cessation of treatment may contribute to the lowered fertility commonly observed following the synchronization of oestrus. The cervical mucus response to injected steroids was recorded in spayed ewes. This was a specific linear response to exogenous oestrogen. Progesterone priming resulted in higher levels of cervical secretions from 24 to 42 hr after the administration of oestradiol benzoate (ODB). Intravenous administration of ODB caused an earlier but short-lived response.

Gestodene: clinical experience with an innovative progestogen used in a combination oral contraceptive preparation

The contraceptive efficacy, tolerance, and safety of a new monophasic oral contraceptive that combines 75 mcg gestodene (delta-15- levonorgestrel) and 30 mcg ethinyl estradiol were studied in 75 women (944 cycles) currently at risk for pregnancy. 20 women were nulliparous. No woman became pregnant during the trial, nor were vital signs of body weight affected by the drug. Cycle control was excellent, with no bleeding irregularities in 92% of the cycles. Serious complications did not occur. The low incidence of side effects, e.g. headache (9%) and breast tenderness (8%), indicated that the gestodene combination was well-tolerated. In a subgroup of 10 women, no changes in routine laboratory tests could be demonstrated after 12 cycles of treatment.

Effect of desogestrel-containing oral contraceptives on vascular reactivity and catecholamine levels

The modifications induced by new oral contraceptives (OC) on blood pressure, great vessel vascular reactivity by color Doppler, and catecholamine levels were investigated. Young healthy women not taking OC (n = 22; controls) or receiving, for > or = 6 months, OC containing desogestrel with either 30 micrograms (n = 14) or 20 micrograms of EE (n = 8) were enrolled. Blood pressure measured at rest in supine position was similar between controls and OC users. The pulsatility index (PI), an indirect index of resistance to blood flow, of axillary artery was significantly higher (p < 0.05) in 30 micrograms than in 20 micrograms EE OC users or controls. A similar trend, albeit not significant, was observed for the internal carotid artery PI. Norepinephrine (p < 0.01) and dopamine (p < 0.05) but not epinephrine levels, were lower in 30 micrograms EE OC users than in 20 micrograms EE OC users or controls. Thus, both 20 micrograms and 30 micrograms EE OC had no negative effect on blood pressure, but the 30 micrograms EE OC tended to increase great vessel resistance to blood flow, independently of catecholamine levels.

A randomized cross-over study on various hormonal parameters of two triphasic oral contraceptives

The effect of two triphasic oral contraceptives (Triquilar [TRQ] and Trisiston [TRS]) containing ethinyl estradiol (EE) and levonorgestrel (LNG) on various hormonal parameters was investigated in 26 women during a cross-over study. TRS consisted of 0.03 mg EE + 0.05 mg LNG (six tablets), 0.04 mg EE + 0.075 mg LNG (six tablets), and 0.03 mg EE + 0.15 mg LNG (nine tablets), whereas TRQ was different in the second phase (five tablets) and third phase (10 tablets). Blood samples were taken on days 6, 11, 21, and 28 of the control and washout cycles and the third treatment cycle. Both formulations inhibited ovulation reliably and decreased the serum levels of gonadotropins, free testosterone, and dehydroepiandosterone sulfate in a time-dependent manner, whereas estradiol and testosterone were already suppressed on day 6, indicating a direct suppressive effect on ovarian steroid synthesis. Prolactin, which rose sporadically in some women, was not significantly changed. In contrast, the levels of sex hormone binding globulin, corticosteroid binding globulin, and cortisol were significantly elevated by 100%. During the hormone-free interval of 7 days, all parameters returned at least partly to baseline. There was no significant difference between the effects of both formulations. The results suggest the possibility of a direct inhibitory effect of contraceptive steroids on ovarian steroid synthesis.

Omitting the first oral contraceptive pills of the cycle does not automatically lead to ovulation

OBJECTIVE

Our purpose was to test the hypothesis that omitting the first three pills of the contraceptive cycle leads to ovulation.

STUDY DESIGN

Ninety-nine women, randomly assigned to 1 of 3 treatments of combined oral contraceptives, completed the study. Treatments contained ethinyl estradiol and either monophasic gestodene, triphasic gestodene, or monophasic desogestrel. Pituitary-ovarian activity was monitored by ultrasonography of the ovaries and assay of serum concentrations of estradiol, progesterone, and follicle-stimulating hormone over 1 normal cycle (study period 1) and 1 cycle after an extended pill-free interval of 10 days (study period 2).

RESULTS

None of the women experienced normal ovulation as evaluated by ultrasonography and serum progesterone concentrations. However, follicle-stimulating hormone reached a maximal serum concentration in most women during the first 7 pill-free days, indicating complete pituitary recovery, and increases in serum estradiol concentrations were seen in each woman although with marked interindividual variation. During study period 2 we found follicles of >18 mm in 24%, 24%, and 40% of the monophasic gestodene, triphasic gestodene, and monophasic desogestrel groups, respectively.

CONCLUSIONS

Follicular growth up to preovulatory size is common in women missing the first one to three pills of their contraceptive cycle. Although this creates the prerequisite for ovulation, normal ovulation did not occur when pill omissions were limited to only 3 days.

A regimen of oral contraceptives restricted to the periovulatory period may permit folliculogenesis but inhibit ovulation

Increased safety of oral contraceptives (OC) has resulted from a reduction in the estrogen and progestin content per tablet. A reduction in the number of hormonally active pills and their placement at critical points within the cycle may provide a novel regimen for further reducing the hormonal content of OC per cycle and their attendant side effects without compromising efficacy. The objective of this study was to determine the effectiveness of two OC regimens that incorporate a delayed start and limited midcycle use of the combination of ethinyl estradiol and norethindrone, and limited use of norethindrone only during the second half of the cycle. Main outcome measures were defined as ovulation, serum concentrations of estradiol (E2), luteinizing hormone (LH), follicle stimulating hormone (FSH), progesterone (P), follicular diameters, and endometrial thickness. Volunteers were issued blister packs containing 28 pills and randomized to one of two groups. Group 1 used a combination of 50 micrograms ethinyl estradiol and 1 mg norethindrone per tablet day 6-10, and 0.70 mg norethindrone only day 11-19. Placebo tablets were used on days 1-5 and day 20-28. Group 2 used a combination of 50 micrograms ethinyl estradiol and 1 mg norethindrone per tablet on day 8-12, and 0.70 mg norethindrone only on day 13-21. Placebo tablets were used on day 1-7 and day 22-28. A total of 20 cycles were studied using 10 volunteers. To assess any possible carryover effect, two successive cycles were studied for each subject. Serum sampling for E2, FSH, LH, and P, and transvaginal ultrasound imaging to assess endometrial thickness and follicle diameter were carried out at 4 day intervals throughout the cycle. One ovulation occurred in 10 cycles in group 1. Five ovulations occurred in 10 cycles in group 2. All ovulations, regardless of group, occurred in the second cycle. Peak E2 concentrations were not significantly different between groups (152.04 +/- 107.1 pg/mL vs 162.1 +/- 56.1 pg/mL [mean +/- SD] for groups 1 and 2, respectively] but occurred earlier in the cycle in group 1. No differences were noted between the groups in serum concentrations of FSH or LH for any given cycle day. Maximum follicle diameters were not different between groups 1 and 2, regardless of ovulatory status (20.5 +/- 8.1 mm2 vs 20.6 +/- 14.2 mm2, respectively). Ultrasound imaging assessment of midcycle follicle growth revealed diameters ranging from 18.5 mm2 to 34.0 mm2 with gradual resolution through the second half of the cycle in anovulatory cycles, and 16.0 mm2 to 23.5 mm2 with abrupt disappearance in ovulatory cycles. Endometrial thickness did not exceed 10 mm for any anovulatory cycle regardless of group, but ranged from 6 to 9 and 6 to 11 during the luteal phase of ovulatory cycles of groups 1 and 2, respectively. Peak serum P concentrations at midluteal phase in ovulatory cycles ranged from 9.2 ng/ml to 18.2 ng/ml. Data from this preliminary study suggest that ovulation may be prevented with a combination of ethinyl estradiol and norethindrone started as late as cycle day 6 and limited to 5 days' duration using norethindrone only for 9 days during the second half of the cycle. Such a restricted regimen may offer both an effective method of contraception and a means of further reducing both estrogen and progestin content per cycle and the possible short and long term adverse side effects of these hormones.

Short-term treatment with levonorgestrel does not antagonize the ethinyl estradiol-induced increase of uterine blood flow in postmenopausal women

The aim of this study was to determine the effect of a short-term ethinyl estradiol/levonorgestrel medication on blood flow in the uterine arteries in postmenopausal women in a prospective placebo-controlled double-blind study. Twenty-one healthy postmenopausal woman at least 2 years after menopause received 60 micrograms ethinyl estradiol (EE) for 14 days followed by 40 micrograms EE plus 125 micrograms levonorgestrel (LNG) for 12 days (total treatment period 26 days). Sonographically, uterine volume, endometrial thickness, and blood flow in the uterine arteries [as reflected by pulsatility (PI) and resistance indices (RI)] were measured. Uterine size increased from 44 to 80 mL (day 14, p < 0.001) and 87 mL (day 26, p = NS). Endometrium grew from 3 to 8 mm (day 14, p < 0.001) and 11 mm (day 26, p = NS). Uterine arterial PI fell from 2.76 to 1.37 (day 14, p < 0.001) and 1.34 (day 26, p = NS), whereas RI fell from 0.9 to 0.68 (day 14 and day 26, p < 0.001). In conclusion, short-term treatment with LNG does not antagonize the vascular effect of EE on the uterine arteries as reflected by PI and RI. This result might have clinical significance in the selection of the progestin used in hormonal replacement therapy.

Modulation of ovarian function by an oral contraceptive containing 30 micrograms ethinyl estradiol in combination with 2.00 mg dienogest

Twenty-two healthy female volunteers with normal ovulatory cycles, aged between 20 and 34 years (27.3 +/- 4.1), were included in a single-center, noncomparative study to investigate the modulation of ovarian function by an oral contraceptive containing 30 micrograms ethinyl estradiol in combination with 2.00 mg dienogest. At baseline, during three treatment cycles and post-treatment, serum levels of luteinizing hormone, follicle-stimulating hormone, 17 beta-estradiol, and progesterone were assayed and ultrasonography was used to measure follicular size and the thickness of the endometrium. The primary efficacy variable was inhibition of ovulation as measured by ovarian activity grading. All volunteers ovulated during the pretreatment cycle. During treatment, none of the subjects had ovulatory cycles, although there was still some ovarian activity in several subjects. During the first treatment cycle, only 4% (1 subject) of cycles showed active follicle-like structures. The frequency of follicle-like structures increased to 33% and 35% during treatment cycles 2 and 3. The frequency of presumptive luteinized unruptured follicle-like structures was 5% (1 subject) and 15% (3 subjects) in treatment cycles 2 and 3. The serum hormone concentrations were effectively suppressed in comparison to baseline. The ovarian activity returned to baseline during the post-treatment period. One subject was excluded from further study because of a medical problem believed unrelated to use of the oral contraceptive. No serious adverse events were recorded during the course of the study. The results of the present investigation indicate that the modulatory effects on ovarian function of the monophasic oral-contraceptive containing 30 micrograms ethinyl estradiol combined with 2.00 mg dienogest lead to adequate suppression of ovarian activity and effective inhibition of ovulation.

A comparative randomized trial on the impact of two low-dose oral contraceptives on ovarian activity, cervical permeability, and endometrial receptivity

In a double-blind randomized study, the suppression of ovarian activity and anti-conceptive effects on the cervix and endometrium were assessed during administration of two low-dose monophasic oral contraceptives (20 micrograms ethinyl estradiol [EE], 500 micrograms norethisterone--Eve 20 [Grünenthal, Aachen, Germany]; 20 micrograms EE, 150 micrograms desogestrel --Lovelle [Organon, Munich, Germany]). One hundred eighteen healthy women (ages: 18-35 years) were studied in 10 investigation centers during medication with either Eve 20 (n = 59) or Lovelle (n = 59). During three treatment cycles, ovarian activity was evaluated by sonographic determination of follicle-like structures (FLS) and by simultaneous assessment of serum endocrine profiles (gonadotropins LH and FSH, ovarian steroids estradiol [E2] and progesterone [P]). While on either treatment, no ovarian activity (as judged by no FLS and/or reduced sex steroid levels) was found in 90.8% (Eve 20) and 97.2% (Lovelle) of all investigated cycles. Follicular activity or cyst formation were detected in 18 of 173 cycles (Eve 20) and in 5 of 175 cycles (Lovelle), respectively. Gonadotropin levels were suppressed (LH < 6 IU/L, FSH < 8 IU/L) in most treatment cycles (Eve 20 76.6% vs. Lovelle: 84.8%). Serum E2 concentrations exceeding 0.1 nmol/L indicated residual follicular activity in 19.3% (Eve 20) versus 12.2% (Lovelle) of all cycles. An estimated by serum P levels over 5 nmol/L, ovulation had presumably occurred in 4.1% (Eve 20) versus 2.9% (Lovelle) of treatment cycles. However, when the sonographical and endocrinological data were combined, no ovulation was documented in any pill cycle. The quality and quantity of the cervical mucus was found to be minimal in the majority of women. Moreover, the endometrial layer was determined to be low by ultrasound during most pill cycles, indicating equally strong suppressive effects on endometrial receptivity by the two contraceptives. These observations suggest that ovarian activity is suppressed in the majority of cycles during use of low-dose contraceptives. This effect may mainly be medicated by pronounced suppression of serum gonadotropin levels. Strong anti-conceptive effects of these formulations on both cervical permeability and endometrial receptivity are additional factors ensuring the contraceptive efficacy of these formulations.

A twelve-month comparative clinical investigation of two low-dose oral contraceptives containing 20 micrograms ethinylestradiol/75 micrograms gestodene and 30 micrograms ethinylestradiol/75 micrograms gestodene, with respect to efficacy, cycle control, and tolerance

The aim of this study was to compare contraceptive reliability, cycle control, and tolerance of an oral contraceptive containing 20 micrograms ethinylestradiol (EE2) and 75 micrograms gestodene (GSD), with a reference preparation containing a similar dose of gestodene but in combination with 30 micrograms ethinylestradiol. A higher incidence of intermenstrual bleeding was apparent under the 20 micrograms EE2 oral contraceptive. For the 20 micrograms EE2 preparation, 47.4% of all women reported spotting at least once over a period of 12 treatment cycles, whereas this figure was 35.5% for the 30 micrograms EE2 pill (p < 0.05). However, the incidence was within a range that corresponds to that of other OCs. The cumulative breakthrough bleeding rates (at least once during the one year of treatment) of 14.5% (20 micrograms EE2) and 11.8% (30 micrograms EE2) of women were not significantly different. In relation to all cycles, the intermenstrual bleeding rates were remarkably lower, indicating that the majority of the volunteers experienced such events only in few cycles under treatment: the spotting rate was 11.5% (20 micrograms EE2) and 7.2% (30 micrograms EE2) of all cycles, and the breakthrough bleeding rate was 2.6% and 1.6% of all cycles, respectively. Three pregnancies were recorded during the study (one in the 20 micrograms EE2 + 75 micrograms GSD group, two in the 30 micrograms EE2 + 75 micrograms GSD group). All three could be explained either by intake irregularities or by circumstances impairing the contraceptive effect. The influence of both treatments on the blood pressure and body weight proved to be extremely slight. Adverse events in both groups were rare and differences in the frequency of adverse events were not apparent. The discontinuation rate due to adverse events, including intermenstrual bleeding, was low (9.8% for 20 micrograms EE2 + 75 micrograms GSD, and 7.2% for 30 micrograms EE2 + 75 micrograms GSD) and was in the lower range known for other oral contraceptives. Both preparations were well accepted by the volunteers. The data obtained demonstrate clinically acceptable cycle control, good tolerance, and a high standard of contraceptive reliability for both drugs. Prescription of the 20 micrograms EE2 preparation could be the first-line therapy in order to provide the lowest amount of EE2 possible. In case of persistent cycle control problems, a switch to the 30 micrograms EE2 drug should be considered.

Multicenter, double-blind, comparative clinical study on the efficacy and acceptability of a monthly injectable contraceptive combination of 150 mg dihydroxyprogesterone acetophenide and 10 mg estradiol enanthate compared to a monthly injectable contraceptive combination of 90 mg dihydroxyprogesterone acetophenide and 6 mg estradiol enanthate

Healthy, regularly menstruating women, aged 14-38 years, were enrolled in a comparative, double-blind, phase III, clinical trial to evaluate the contraceptive efficacy and acceptability of a combination of 90 mg dihydroxyprogesterone acetophenide with 6 mg estradiol enanthate compared to the commercially available contraceptive combination of 150 mg dihydroxyprogesterone acetophenide with 10 mg estradiol enanthate. Subjects received the contraceptive combination intramuscularly, between the 7th and 10th day of each menstrual cycle, during 12 consecutive menstrual cycles. Approximately 60% of the subjects in both groups completed the study. Principal reasons for discontinuation were personal, nonmedical reasons. Principal medical reasons for discontinuation were menstrual-related, irregular bleeding being the most frequent. Differences in menstrual patterns between the two groups did not lead to differences in discontinuation rates. Three contraceptive failures occurred during the trial, one in Group A (90/6 mg) and two in Group B (150/10 mg), indicating that the lower dose formulation is at least as efficient as the higher dose.

Clinical experience of a combined oral contraceptive with very low dose ethinyl estradiol

BACKGROUND

The risk of thromboembolic events related to the ethinyl estradiol (EE) dose in oral contraceptive (OC) pills has led to a further dose reduction.

METHODS

An OC pill with 150 micrograms desogestrel combined with only 20 micrograms EE was compared with a pill containing the same dose of desogestrel but 30 micrograms of EE in a Scandinavian multicentre study with follow-up visits after 3, 6 and 12 months.

RESULTS

In almost 5,000 cycles with each pill the numbers of pregnancies due to method failure with the lower and higher EE dose pills were 0 and 2, respectively. Irregular bleedings were slightly more common with the lower EE dose, but tended to decrease over the year of study. Other side effects were uncommon. Regarding metabolic effects, both pills tended to raise the plasma HDL level and the lower EE dose pill also reduced LDL. Free testosterone was reduced by two-thirds with both pills, showing beneficial effects on acne.

CONCLUSIONS

It is concluded that both these pills are reliable and safe, but that many women would accept a slightly greater risk of irregular bleeding with the 20 micrograms EE dose pill in exchange for a reduction in potential risk related to the estrogenic component of OC pills.

Antiepileptic medication and oral contraceptive interactions: a national survey of neurologists and obstetricians

Hepatic enzyme-inducing antiepileptic drugs (AEDs) lower oral contraceptive (OC) sex hormone levels approximately 40% and increase the risk of unplanned pregnancies in women with epilepsy. AEDs also increase the risk of birth defects in offspring of women with epilepsy. We performed a national survey to determine obstetricians' and neurologists' knowledge of OC and AED interactions and the risk of birth defects for women with epilepsy taking AEDs. We received responses to a mailed questionnaire from 160 of 1,000 neurologists (16%) and 147 of 1,000 obstetricians (15%) from 47 states. Practice demographics and ages of responders were typical for U.S. neurologists and obstetricians. Ninety-one percent of neurologists and 75% of obstetricians said they treat women with epilepsy of child-bearing age. Only 4% of the neurologists and none of the obstetricians, however, knew the effects of the six most common AEDs on OCs, even though 27% of neurologists and 21% of obstetricians reported OC failures in their patients taking AEDs. Although increasing OC doses can compensate for insufficient OC sex hormone levels due to AEDs, most physicians do not increase the doses. Even though the risk of birth defects for the offspring of women with epilepsy is 4 to 6%, up from the background level of 2%, 44% of neurologists thought the risk was lower (0 to 3%), and some of the respondents guessed that it was as high as 50%. Many neurologists and obstetricians do not have accurate information to counsel women with epilepsy properly about their contraceptive and pregnancy choices.

The effect of oestrogen dose and progestogen type on haemostatic changes in women taking low dose oral contraceptives

OBJECTIVE

To determine the effect of oestrogen dose and progestogen type on the coagulation and fibrinolytic systems of a group of normal healthy women taking three different oral contraceptive combinations.

DESIGN

Plasma levels of factor VII, X, antithrombin III, protein C, fibrinogen, tissue plasminogen activator activity, plasminogen activator inhibitor I antigen and fibrin (D-dimer) degradation products were measured at pretreatment, 6, 14, 22 weeks of treatment and at 6 weeks post-treatment in a group of 67 women taking either 30 micrograms ethinyloestradiol/150 micrograms desogestrel (n = 21), 20 micrograms ethinyloestradiol/150 micrograms desogestrel (n = 24), 30 micrograms ethinyloestradiol/75 micrograms gestodene (n = 22).

PARTICIPANTS

Sixty-seven healthy normal women, 18 to 34 years, smoking fewer than 15 cigarettes per day. The subjects were within 10% of their normal body weight and had no history of thromboembolic disease.

SETTING

Coombe Women's Hospital and St James's Hospital, Dublin, Ireland.

RESULTS

Factor VII and X levels were significantly raised on treatment with both the 30 micrograms ethinyloestradiol/desogestrel and gestodene combinations. Higher levels of factor VII activity were observed in the 30 micrograms ethinyloestradiol/desogestrel combination compared with the gestodene combination. Factor VII and X were not significantly affected by the 20 micrograms ethinyloestradiol combination. Increased plasminogen, fibrinogen and D-dimer levels and decreased plasminogen activator inhibitor I antigen levels were observed during the treatment phases in all three groups. Antithrombin III and protein C activity did not change during treatment with any of the oral contraceptives studied.

CONCLUSIONS

Low dose oral contraceptives cause an activation of the coagulation system which is balanced by an activation of the fibrinolytic system. Reducing the dose of ethinyloestradiol from 30 micrograms to 20 micrograms reduces the effect on factor VII and X. This effect can be modified by the progestogen. The lesser effect of the 20 micrograms combination may make this a safer option for some women than pills containing a higher dose of oestrogen.

Changes in haemostatic variables induced by oral contraceptives containing 50 micrograms or 30 micrograms oestrogen: absence of dose-dependent effect on PAI-1 activity

Several studies have suggested a dose-response relation between the oestrogen content of oral contraceptive (OC) and the risk of both venous thrombosis and arterial disease, when oestrogen doses were higher than 50 micrograms. However, there is no clear epidemiological evidence for a decrease in thrombotic risk with formulations containing less than 50 micrograms oestrogen. Therefore, we investigated haemostatic variables in users of OC containing either 30 micrograms (35 women) or 50 micrograms (29 women) ethinyl estradiol as compared with non users (64 women) matched for age and smoking status. Mean values of antithrombin activity were significantly lower in 30 micrograms or 50 micrograms oestrogen users than in non users (96% and 98% vs 105%, respectively, p < 0.001), but they were not significantly different between the two groups of OC users. There was a significant increase in mean values of factor VII antigen in women taking either 30 micrograms or 50 micrograms oestrogen as compared with non users (96% and 101% vs 85%, respectively, p < 0.005). Although the difference between both groups of OC users was not significant, a positive linear trend in factor VII levels was observed within the 0-50 micrograms oestrogen range (p < 0.001). Mean levels of fibrinogen were slightly higher in 30 micrograms or 50 micrograms oestrogen users than in non users (2.71, 2.66 g/l vs 2.55 g/l, respectively), but there was no significant difference between the three groups.(ABSTRACT TRUNCATED AT 250 WORDS)

A changing pattern in the association of oral contraceptives and the different groups of congenital limb deficiencies

A case-control study on different groups of isolated congenital limb deficiency was performed in a ten-year population-based and revised Hungarian data set. A higher rate of one contraceptive pill type with relatively high dose (ethynodiol diacetate 1.0 mg + ethinyloestradiol 0.05 mg) used in the periconceptional period was found in the mothers of cases with terminal transverse defect (adjusted relative odds 1.9 with 95% confidence interval of 1.1-3.4). This risk is minimised by the use of recent low-dose pills.

Effect of oestrogen dose on whole blood platelet activation in women taking new low dose oral contraceptives

Oral contraceptive use is known to cause changes in the haemostatic system. These changes are thought to be related to oestrogen dose and to provide a possible link between the increased risk of thromboembolic disease known to occur in women taking oestrogen containing oral contraceptives. This study measured whole blood platelet activation, serially, in women taking oral contraceptives containing 20 micrograms and 30 micrograms ethinyloestradiol combined with desogestrel. Increased levels of ADP and arachidonic acid induced aggregation were observed in women taking the 30 micrograms ethinyloestradiol combination. Platelet release of beta-thromboglobulin (beta TG) was also significantly increased. Increased collagen induced aggregation was observed but this failed to reach statistical significance for the individual treatment groups. In women taking the 20 micrograms ethinyloestradiol combination, a significant increase was only observed when platelets were stimulated with arachidonic acid. Platelet factor 4 (PF4) levels were unchanged in both groups. Significantly higher levels of beta TG were observed in women taking the 30 micrograms ethinyloestradiol combination compared with women taking the 20 micrograms ethinyloestradiol combination. These results show that oral contraceptive use is associated with platelet activation. Women taking the 20 micrograms ethinyloestradiol combination show less changes in platelet activation than women taking the 30 micrograms ethinyloestradiol combination. This lower dose pill may therefore be particularly suitable for high risk women wishing to use oral contraception.

Haemostasis profile in smoking and nonsmoking women taking low-dose oral contraceptives

The effects of oral contraceptives on coagulation in 258 nonsmoking and in 190 smoking women were determined. In smokers and in nonsmokers taking oral contraceptives, fibrinogen and fibrinopeptide A concentrations were higher than in oral contraceptive nonusers. In nonsmokers, oral contraceptives increased antithrombin III activity. The effects on coagulation of oral contraceptives with a different ethinylestradiol content (from 35 mcg to 20 mcg) were then evaluated in 333 of these women. The biggest changes in coagulation were observed in smokers taking the preparation with the highest estrogen content. Reduction of the ethinylestradiol dose caused a decrease of the changes in coagulation induced by oral contraceptives both in smokers and nonsmokers. These results might suggest that during oral contraception the coagulation system is affected mainly in smokers and that the decrease of the estrogen dose might lower the effects of the association of smoking and oral contraception on coagulation.

Menstrual impact of contraception

Persistent bleeding is a common reason for the discontinuation of contraception. Standard terminology for describing bleeding patterns by reference period is presented. Observed bleeding patterns with oral contraceptives, depot medroxyprogesterone acetate, the levonorgestrel subdermal implant, and intrauterine devices are described. Bleeding days are least with oral contraceptives that are highest in progestin and estrogen potency and dose, but the ratio of the two steroids is also important. Published studies suggest that oral contraceptives containing new nonandrogenic progestins have bleeding patterns as acceptable as older low estrogen formulations. Approaches to the evaluation and treatment of intermenstrual bleeding with contraceptive methods are reviewed. Patient education on expected bleeding patterns is essential to compliance and continuation.

Efficacy and safety of a monophasic and a triphasic oral contraceptive containing norgestimate

Both monophasic and triphasic formulations of ethinyl estradiol plus norgestimate, a progestin with marked progesterone-receptor affinity and minimal androgen-receptor affinity, have been evaluated in numerous clinical studies designed to determine if norgestimate's receptor-binding profile provides enhanced safety without a reduction in efficacy. To date clinical trials have shown that both formulations of ethinyl estradiol/norgestimate offer contraceptive efficacy equivalent to that of other oral contraceptives. Monophasic ethinyl estradiol/norgestimate was associated with an incidence of breakthrough bleeding and spotting similar to that of monophasic ethinyl estradiol/norgestrel and an incidence of amenorrhea less than that of ethinyl estradiol/norgestrel. Cycle control with triphasic ethinyl estradiol/norgestimate was similar to that with monophasic ethinyl estradiol/norgestimate. Weight gain and elevated blood pressure were insignificant in clinical trials with both fixed-dose and phasic ethinyl estradiol/norgestimate formulations. Perhaps of greatest importance, both monophasic and triphasic ethinyl estradiol/norgestimate formulations consistently showed favorable impact on metabolic parameters, including elevations in serum high-density lipoprotein cholesterol, and reductions in the low-density lipoprotein/high-density lipoprotein ratio, the parameter considered most sensitive for atherosclerotic risk. Both monophasic and triphasic ethinyl estradiol/norgestimate formulations were associated with minimal and clinically neutral effects on carbohydrate metabolism.

Pharmacokinetics of once-a-month injectable contraceptives

The addition of a short- or medium-acting estrogen ester to the long-acting progestins depot-medroxyprogesterone acetate (DMPA) and norethisterone enanthate (NET-EN) to produce "combined" injectable formulations has proved a successful strategy in the development of once-a-month injectable contraceptives. Recent clinical pharmacokinetic studies undertaken on once-a-month injectable contraceptives in various WHO Collaborating Centers have guided the selection of the estrogen-progestogen combinations, ratios and dose schedules. At least three combined once-a-month injectable preparations exhibit acceptable pharmacokinetic and pharmacodynamic profiles; however, further improvement in the design of optimal estrogen/progestin injectables are expected during this decade.

Insulin sensitivity is decreased in normal women by doses of ethinyl estradiol used in oral contraceptives

OBJECTIVE

We determined the independent effects of various doses of ethinyl estradiol used in oral contraceptives or norethindrone acetate, as well as their combination, on insulin sensitivity in normal women.

STUDY DESIGN

Thirty-three normal ovulatory female volunteers were recruited for this study. Insulin tolerance tests were performed after carbohydrate loading to determine the kinetic disappearance of glucose and insulin. After initial testing the women were randomized into four groups: ethinyl estradiol 20 micrograms, 35 micrograms, and 50 micrograms and norethindrone 1 mg. Insulin tolerance tests were repeated after 1 month of treatment and again after a second month, when all ethinyl estradiol groups received the addition of norethindrone 1 mg to their doses of ethinyl estradiol. Plasma glucose and insulin were measured, and insulin sensitivity (K(itt) glucose) and the disappearance of insulin (K(itt) insulin) were calculated.

RESULTS

All groups were comparable at baseline, and no significant changes in fasting glucose and insulin were evident with treatment. After ingestion of 50 micrograms ethinyl estradiol the K(itt) glucose value decreased significantly (p < 0.03) and ingestion of 20 micrograms and 35 micrograms showed individual changes, but as groups the changes were not statistically significant. All ethinyl estradiol groups combined had a significant decrease in K(itt) glucose (p < 0.01). Norethindrone 1 mg alone did not change K(itt) glucose values, and after the addition of norethindrone to ethinyl estradiol, K(itt) glucose values normalized. K(itt) insulin values were also lower with treatment but were lower with ethinyl estradiol plus norethindrone compared with ethinyl estradiol alone (p < 0.04), suggesting an attenuation of insulin clearance with the progestin.

CONCLUSION

Ethinyl estradiol alone decreases insulin sensitivity, and this may occur at lower doses, but norethindrone 1 mg does not appear to do so. However, progestins may alter insulin clearance.

Safety and efficacy of a triphasic oral contraceptive containing desogestrel: results of three multicenter trials

This report combines the data obtained in three multicenter efficacy studies with a new triphasic oral contraceptive combination containing desogestrel (DSG) and ethinyl estradiol (EE). The studies were conducted at 40 investigational sites in the United States (38 centers) and Canada (2 centers) in support of the FDA approval of the product. In total, 1,095 subjects were exposed to the study medication for 11,231 cycles, corresponding to approximately 864 woman-years of use. Of these subjects, 414 completed at least 13 cycles of treatment. Contraceptive efficacy was high; six pregnancies occurred during the in-treatment period (two due to method failure and four due to user failure), corresponding to Pearl Indices of 0.23 and 0.46, respectively. The incidence of irregular bleeding was low, and the acceptability was excellent as evidenced by the low incidence of drug-related drop-outs. No drug-related serious adverse experiences were reported, and the incidence of other drug-related adverse experiences was generally low and decreased with continued use. No effects were seen on blood pressure, body mass index, laboratory parameters, cervical cytology and breast nodularity. These studies demonstrate that triphasic DSG/EE is an effective and acceptable triphasic oral contraceptive preparation with excellent cycle control and no significant physiologic effects.

Hemostatic and metabolic effects of lowering the ethinyl-estradiol dose from 30 mcg to 20 mcg in oral contraceptives containing desogestrel

The metabolic and hemostatic effects of two oral contraceptives containing 150 mcg desogestrel and 20 mcg ethinyl-estradiol (EE) (MERCILON) or 30 mcg EE (MARVELON) were compared in order to examine the effect of reducing the EE dose in contraceptive pills. Forty-nine women participated in this randomized study during 6 cycles. In both groups, there was a significant increase in triglycerides, HDL-cholesterol and apoprotein A1; the same increase was observed for SBP and CBG. Slight and transient variations of fasting blood glucose levels were seen in the 30 mcg EE group and in the two groups for fasting insulin levels. The increase in renin substrate was significantly higher with the 30 mcg EE than with the 20 mcg EE pill. In both groups, plasminogen increased significantly, but antithrombin III, total and free protein S and fibrinogen decreased significantly only in women taking the 30 mcg EE pill, whereas there was no significant change in the 20 mcg EE group. Reducing the dose of EE in oral contraceptives from 30 mcg to 20 mcg minimizes their impact on renin substrate and hemostatic parameters.

Liver damage from low-dose oral contraceptives

OBJECTIVE

To study whether the decrease in the content of oestrogen and gestagen in modern low-dose oral contraceptives (OC) has yielded a lower incidence of adverse liver reactions, and to describe the biochemical pattern of the adverse liver reactions from low-dose OC.

DESIGN

We surveyed all liver reactions from OC reported to SADRAC (Swedish Adverse Drug Reactions Advisory Committee) from 1966 to 1989.

MAIN OUTCOME MEASURE

Incidence of reported adverse liver reactions (number of reported adverse reactions/OC sales in defined daily dose [DDD]).

RESULTS

There was a sharp decline in the number of reports during the studied period, suggesting changes in reporting habits. However, there was also a significantly lower incidence of reports for medium-compared to high-oestrogen dose OC, and a further decrease, albeit non-significant, in incidence with low-oestrogen dose OC. Furthermore, in three comparisons of pairs of OC that differed only in the gestagen dose, there was a strong trend towards a higher reporting rate with higher gestagen dose. Cholestatic and hepatocellular liver enzyme patterns were equally frequent in patients with adverse reactions from low-dose oestrogen OC. There was no report of liver tumours related to use of low-oestrogen dose OC.

CONCLUSION

There seems to be a decrease in the incidence of adverse liver reactions related to lower contents of both oestrogen and gestagens in OC of the combined-preparation type.

A prospective randomized comparison of levonorgestrel with the Yuzpe regimen in post-coital contraception

A prospective randomized study was conducted at the Family Planning Association of Hong Kong to compare the efficacy of the Yuzpe regimen and levonorgestrel (0.75 mg for two doses 12 h apart) in post-coital contraception. A total of 424 subjects were recruited into the Yuzpe group and 410 subjects into the levonorgestrel group; 77 subjects in the Yuzpe group and 79 subjects in the levonorgestrel group had further acts of intercourse during the treatment cycle. Fifteen pregnancies (3.5%) occurred in the Yuzpe group and 12 pregnancies (2.9%) in the levonorgestrel group. After excluding the patients who had further acts of intercourse, the failure rates in the Yuzpe group and the levonorgestrel group were 2.6 and 2.4% respectively. The incidence of nausea, vomiting and fatigue in the Yuzpe group was significantly higher than those in the levonorgestrel group. We conclude that levonorgestrel is an effective drug for post-coital contraception with a lower incidence of side-effects than the Yuzpe regimen.

Mifepristone (RU 486) compared with high-dose estrogen and progestogen for emergency postcoital contraception

BACKGROUND

Mifepristone (RU 486) is a synthetic steroid with potent antiprogestational and antiglucocorticoid properties that provides an effective medical method of inducing abortion in early pregnancy. Since progesterone is essential for implantation, we tested the use of mifepristone for emergency postcoital contraception.

METHODS

We studied 800 women and adolescents requesting emergency postcoital contraception who had had unprotected intercourse within the preceding 72 hours. A total of 398 women and adolescents were randomly assigned to treatment with 100 micrograms of ethinyl estradiol and 1 mg of norgestrel, each given twice 12 hours apart (standard therapy), and 402 women and adolescents were randomly assigned to receive 600 mg of mifepristone.

RESULTS

None of the women and adolescents who received mifepristone became pregnant, as compared with four of those who received standard therapy; the difference in failure rates between the two regimens was not statistically significant. The number of pregnancies in each group was significantly lower than the number expected according to calculations based on the day of the cycle during which intercourse had taken place (P less than 0.001). In many subjects the stage of the cycle as calculated by menstrual history was inconsistent with measurements of plasma progesterone or urinary pregnanediol excretion. The subjects treated with mifepristone reported less nausea (40 percent vs. 60 percent) and vomiting (3 percent vs. 17 percent) on the day of treatment, as well as lower rates of other side effects, than the subjects treated with the standard regimen, but they were more likely to have a delay in the onset of the next menstrual period (42 percent vs. 13 percent).

CONCLUSIONS

Mifepristone is a highly effective postcoital contraceptive agent that, if used more widely, could help reduce the number of unplanned and unwanted pregnancies.

Hormone levels and anogenital swelling of female chimpanzees as a function of estrogen dosage in a combined oral contraceptive

A combined oral contraceptive consisting of ethinyl estradiol (EE2) in three dosages (50, 100, and 400 micrograms) and norethindrone (0.5 mg) was given to female chimpanzees to determine the effect on endogenous sex hormone levels and anogenital swelling. Serum levels of EE2 increased with increasing dosages of EE2, estradiol decreased, and luteinizing hormone, progesterone and testosterone were maintained at approximately midfollicular phase levels. Urinary levels of EE2 glucuronide increased with the increasing dosages of EE2, whereas estrone and pregnanediol glucuronide were essentially undetectable. The cyclic increase in female anogenital swelling was abolished when the norethindrone was combined with 50 micrograms of EE2 and relatively constant and low levels of swelling were recorded. Relatively constant but successively higher levels of swelling were recorded when the norethindrone was combined with the higher dosages of EE2. These effects of oral contraceptives on female genital tissues are relevant to our laboratory studies of sexual behavior in chimpanzees given oral contraceptives and could also have implications for women taking oral contraceptives.

Interrelationship of serum levonorgestrel and sex hormone-binding globulin levels following vaginal and oral administration of combined steroid contraceptive tablets

Ten women were treated daily with a standard dose contraceptive tablet containing 0.25 mg levonorgestrel (LNG) in combination with 0.05 mg ethinylestradiol. Five women used the tablet vaginally, while the other five used it orally. Blood samples were taken at frequent intervals on the first day of treatment and after 1 and 2 hours on treatment days 7 and 14. Serum LNG levels were measured by radioimmunoassay, and sex hormone-binding globulin (SHBG) was quantitated by charcoal assay. On day 1, peak concentrations of LNG (5.1 ng/ml) occurred within 2 hours in the oral group, whereas in the vaginal group a peak of 2.2 ng/ml was reached after 4 hours. After 24 hours, mean serum concentrations of LNG were 1.1 and 0.69 ng/ml in the oral and vaginal groups, respectively. In both groups, mean LNG concentrations increased dramatically on days 7 and 14 compared to day 1. There was no significant difference between the two groups in LNG concentrations, except after 2 hours on day 1. SHBG levels were increased after one day of treatment. By day 14 of treatment, there was a 3.5- to 4.5-fold rise in SHBG levels from pretreatment values in both groups. However, there was no significant difference in SHBG levels between the two groups throughout the study. A high correlation was found between serum levels of SHBG and LNG in both the vaginal and oral groups. The results suggest that the increase in serum LNG levels in women receiving combined contraceptive tablets either vaginally or orally is due to increased levels of SHBG. Also, the measured concentrations of LNG in the vaginal group are consistent with the previously reported clinical contraceptive efficacy of combined contraceptive tablets administered vaginally.

A comparative study of 35 mcg and 50 mcg combined oral contraceptives: results from a multicenter clinical trial

A comparative multicenter clinical trial of two combined oral contraceptives (OCs) differing only in the estrogen content (35 mcg ethinyl estradiol versus 50 mcg mestranol) was conducted at five clinics located in Yugoslavia, Egypt, Sri Lanka, Costa Rica and Mexico. The trial was designed to determine the differences between Norinyl 1+35 (Syntex) and Norinyl 1+50 (Syntex) in rates and reasons of discontinuation, and frequency of selected side effects which might contribute to method discontinuation. This report includes analysis of 1698 women, all of whom were interval patients (at least 42 days but within 26 weeks postpartum), randomly allocated to one of the above OCs between October 1982 and January 1984. Follow-up visits were scheduled at 1, 4, 8 and 12 months after admission. Significantly more women in the Norinyl 1+35 group (p less than .001) reported intermenstrual bleeding (primarily staining and spotting), as well as an increase in the occurrence of intermenstrual bleeding compared to women in the Norinyl 1+50 group. There were no significant differences between the groups for side effects with the exception of more women in the Norinyl 1+50 group (p less than .05) reporting breast discomfort. The lost to follow-up rate at 12 months was 19.3% for both the Norinyl 1+35 and the Norinyl 1+50 groups. The total discontinuation rate (including women lost to follow-up) at 12 months was 43.5% for the Norinyl 1+35 group and 41.0% for the Norinyl 1+50 group. There were no significant differences between the two groups for gross cumulative life table discontinuation rates (p greater than .05). There were six accidental pregnancies attributed to user failure reported during the study period; four in the Norinyl 1+35 group and two in the Norinyl 1+50 group.

Hirsutism: metabolic effects of two commonly used oral contraceptives and spironolactone

Fifty-one hirsute women were randomly treated for nine months with ethinyl estradiol 35 ug plus norethindrone 0.4 mg or 30 ug ethinyl estradiol plus 1.5 mg norethindrone acetate if they needed contraception or spironolactone 200 mg daily if they did not. Metabolic evaluations in response to therapy demonstrated triglyceride elevations with the two oral contraceptives but not with spironolactone. While systolic blood pressure was lower with spironolactone, fasting insulin levels were higher as opposed to either low-dose oral contraceptive preparation. Ethinyl estradiol 30 ug plus 1.5 mg norethindrone acetate lowered 3-alpha-diol glucuronide levels, yet ethinyl estradiol 35 ug plus norethindrone 0.4 mg and spironolactone were more effective in lowering Ferriman-Gallwey Scores. Treatment strategies for hirsute women need to consider metabolic consequences as well as efficacy.

Postponement of withdrawal bleeding with a monophasic oral contraceptive containing desogestrel and ethinylestradiol

This study investigated the ability of a monophasic sub-50 oral contraceptive, containing desogestrel and ethinylestradiol, to postpone withdrawal bleeding in normal healthy women. In the analyzed group of 105 regular users of Marvelon, about 75% did not experience any vaginal bleeding during the 21 days of postponement. A 95% confidence interval was calculated which suggests that the percentage of women able to postpone their withdrawal bleeding successfully for 19 days ranges between 67.0% and 83.5%. Women with no vaginal blood loss in the postponement period were more willing to try this method of postponement again, compared to women who experienced vaginal blood loss in the postponement period. This difference was statistically significant. Nevertheless, the majority of women with vaginal blood loss were also willing to try this method again if necessary. The study results suggest that Marvelon offers an effective and acceptable method of postponing withdrawal bleeding for three weeks for most regular users of this contraceptive.

Oral contraceptives and antithrombin III: variations by dosage and ABO blood group

A randomized clinical trial of oral contraceptives evaluated 67 women on a regimen of 50 micrograms ethinyl estradiol and 1.0 mg norethindrone, 61 women on a regimen of 35 micrograms ethinyl estradiol and 1.0 mg norethindrone, and 64 women on a regimen of 35 micrograms ethinyl estradiol and 0.5 mg norethindrone. ABO blood group type was determined in all women. At baseline and at 3, 6, and 9 months, plasma antithrombin III levels, by both an immunologic and an activity method, and selected plasma levels of the contraceptive steroids were measured. Antithrombin III levels for all oral contraceptive groups combined decreased from baseline by 19.7% and 28.8% for the immunologic and activity methods, respectively. Analysis of interrelationships among antithrombin III by activity method, oral contraceptive type, and ABO blood group showed larger declines in antithrombin III for type O women using the highest estrogen dose preparation (31.6%) and for non-type O women using the lowest progestin dose preparation (38.9%). Plasma levels of contraceptive steroids also were related to changes in the most extreme levels of antithrombin III.

Ovarian response in superovulated cycles after suppression with oral contraceptive steroids

The endocrine response to controlled ovarian hyperstimulation was reviewed in 94 women undergoing in vitro fertilization during 114 cycles. The purpose of this review was to evaluate the effect of short-term oral contraceptive suppression on the recovery of pituitary gonadotropin function and subsequent controlled ovarian hyperstimulation. Seventy-three cycles (64%) were adequate for oocyte retrieval. In 41 cycles (36%) hyperstimulation was discontinued. The serum 17 beta-estradiol value in women with a poor response was 57 +/- 50 pg/ml on day 8 compared with 376 +/- 334 pg/ml in the women who completed in vitro fertilization (p less than 0.05). The majority of women (84.2%) had a prompt response to controlled ovarian hyperstimulation after short-term oral contraceptive suppression. Most discontinuations were due to dominant follicle selection or luteinizing hormone surge and not to oversuppression by short-term oral contraceptives. Clinical pregnancies occurred in 15 women (20.5% of harvests).

The pharmacokinetics of ethynylestradiol in the presence and absence of gestodene and desogestrel

Single doses of ethynylestradiol (30 micrograms) were given alone and in combination with either gestodene (75 micrograms) or desogestrel (150 micrograms) to 10 healthy female volunteers. The doses of steroids were given both orally and by i.v. infusion over 5-7 minutes. Blood samples were taken at regular intervals over 24 hours. The area under the plasma concentration versus time curve (AUC) for oral EE2 alone was 867 +/- 338 pg/ml x h, for oral EE2 in the presence of gestodene it was 795 +/- 206 pg/ml x h and for oral EE2 in the presence of desogestrel it was 614 +/- 132 pg/ml x h. With either gestodene or desogestrel present, the AUC of EE2 was not significantly different from that found when EE2 was given alone. In addition, there was no significant difference between EE2 + gestodene and EE2 + desogestrel. Comparing the relative oral and iv doses, the bioavailability of EE2 (alone) was 59.0 +/- 13% (n = 6), for EE2 plus gestodene it was 62.1 +/- 10% and for EE2 in the presence of desogestrel it was 62.1 +/- 4.4%. The clearance of EE2 (alone) was 19.9 +/- 5.5 l/h and in the presence of gestodene it was 19.4 +/- 9.6 l/h. The clearance of EE2 in the presence of desogestrel appeared slightly greater at 27.7 +/- 8.9 l/h but none of these clearance values were significantly different from each other. The urinary excretion of 6-beta-hydroxy cortisol was similar after all 6 doses of EE2. These data strongly suggest that following single dose administration, neither gestodene nor desogestrel have any inhibitory effect on the metabolism of EE2 or alter its kinetics to any clinically significant extent.

Long-acting hormonal contraceptives for women

Following the development and widespread use of oral hormonal contraceptives, it became evident that alternative long-acting delivery systems would be required to improve contraceptive practice in some cultural settings where injectable or subdermal routes of administration are preferred. Nowadays, long-acting contraceptives constitute an important option in family planning services in many parts of the world. Indeed, two long-acting injectable contraceptives containing just a synthetic progestogen (depot-medroxyprogesterone acetate (DMPA) and norethisterone enantate (NET-EN)) have been in clinical practice for more than 20 years. The World Health Organization's (WHO) Special Programme of Research in Human Reproduction, in collaboration with the U.S. National Institute of Child Health and Human Development (NICHD) and universities primarily in developing countries undertook a synthesis programme aimed at producing an improved injectable preparation by developing new derivatives of known steroids. One such compound (levonorgestrel 17-butanoate) is now at the stage of Phase II clinical testing. In addition, the Special Programme has developed and improved once-a-month injectable formulations and assessed their safety and efficacy in different countries worldwide. After large scale clinical testing, at least two progestogen-estrogen combinations have reached the point of introductory trials.

Effect of oral contraception on water-suppressed proton NMR spectra of plasma

Lipid linewidths were measured in the plasma proton spectra of young women. The individuals taking a contraceptive pill associating ethinyloestradiol and levonorgestrel or norethisterone were found with an average linewidth 2.5 Hz narrower than controls. As this drug regimen systematically induces an increase in plasma VLDL and a decrease in HDL/LDL ratio, our observation supports the theory that the Fossel test reflects plasma lipids abnormalities in cancer patients.

Oral contraceptives stimulate the excretion of clofibric acid glucuronide in women and female rats

1. Glucuronidation of clofibric acid, the pharmacologically active form of the hypolipidemic drug clofibrate was investigated in a human population, either in vitro with liver homogenates from biopsies, or after ingestion of the drug and determination of the urinary metabolite. No difference in the glucuronidation rate according to age of the patients was observed. Bilirubin but not clofibric acid glucuronidation was significantly higher in women (106% increase), when expressed per gram of tissue. 2. The excretion of clofibryl glucuronide in women who took oral contraceptives was significantly enhanced by 25%. 3. In female rats, treatment with the contraceptive agent norethindrone also stimulated by 48% the formation of clofibrylglucuronide in liver microsomes.

Pharmacokinetics of levonorgestrel in 18 women after 1 month of treatment with a triphasic oral contraceptive

A triphasic levonorgestrel (LNG)- and ethinylestradiol-containing oral contraceptive was administered to 18 women. Plasma samples were obtained throughout a treatment cycle just before drug administration and on the last treatment day (day 21), several plasma samples were collected from each individual up to 48 h postadministration. LNG was determined by radioimmunoassay in all plasma samples. In addition, the concentration of sex-hormone-binding globulin (SHBG) was determined in plasma samples collected from the same subjects during treatment, as well as during a pre- and a posttreatment cycle. During the treatment cycle, plasma levels of LNG determined just before drug administration increased and reached steady state at about day 16. This increase was due to an increased dose of LNG according to the triphasic dose regimen, a concomitantly ethinylestradiol-induced increase in SHBG and due to pharmacokinetic accumulation, since LNG had a terminal half-life of approximately 28.5 h and the dosing interval was 24 h. Steady-state levels and pharmacokinetic parameters of LNG determined on the last day of treatment were in good accordance with previously published results.