CONTRACEPTION

BLEEDING AND OVULATION CONTROL WITH USE OF A SMALL CONTRACEPTIVE VAGINAL RING RELEASING LEVONORGESTREL AND ESTRADIOL

J. Toivonen P. LHhteenm;iki T. Luukkainen Steroid Research Laboratory, Department of Medical Chemistry, SF-00170 Helsinki 17, University of Helsinki, Finland

ABSTRACT Levonorgestrel and estradiol releasing contraceptive vaginal rings (CVR) with an outer diameter of 50 rmn were used by twenty women. The treatment was given in three-week cycles followed by one treatment-free week. The treatment was planned to cover Six cycles. All subjects kept records of bleeding and were controlled clinically in the course of treatment. Three subjects were followed by blood sampling. Plasma levonorgestrel, estradiol, progesterone and gonadotropins were determined. The subjects experienced no difficulties in using the CVR and 90 per cent continued the treatment through the whole experimental period of six months. One subject discontinued after three cycles because of irregular bleedings and one subject after five cycles ,because of urinary discomfort. Regular bleedings were observed only in three subjects and in nine cases the bleeding started with the CVR -in situ during the last days of the three-week treatment period. Breakthrough bleeding occurred in the remaining eight subjects. The subjective side-effects were as follows: weight gain in four subjects, oedema in one subject and urinary discomfort in one subject. Pituitary function was not generally suppressed as judged by plasma gonadotropins. Out of the three subjects studied, two experienced ovulatory plasma progesterone concentrations.

Accepted

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1979 VOL. 20 NO. 1

June

4,

1979

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CONTRACEPTION

INTRODUCTION Contraception based on the release of progestin from a polysiloxane contraceptive vaginal ring (CVR) has been intensively studied since the method was introduced in 1970 (1). The studies have made use of CVRs with different design and impregnated with different progestins with or without estradiol. The outer diameter of the CVRs has been 58 mm or more. The method per se has proved to be well accepted by the users. A shell-design CVR impregnated with levonorgestrel and estradiol, has proved to result in inhibition of ovulation in nearly all treatment cycles and also in favourable bleeding control (2,3). In order to further improve the acceptance of the method, a smaller CVR was introduced. In this study, a shell-design levonorgestrel-estradiol CVR with an outer diameter of 50 mm was clinically evaluated. In three selected subjects plasma levonorgestrel, estradiol, progesterone as well as LH and FSH concentrations were measured.

MATERIAL AND METHODS The contraceptive vaginal rings (CVR) were prepared as described previously (2). The outer diameter of the CVRs was 50 mm and the internal diameter 32 mm. They contained levonorgestrel (97-140 mg) and estradiol (46-66 mg) and were manufactured by Dr. Theodore M. Jackanicz of the Population Council, New York, USA. Twenty healthy, volunteer women participated in the study. All subjects experienced regular menstrual cycles. The ages of the women varied between 20 and 36 years. Thirteen of them were parous and twelve were married. All subjects had a regular sexual life. In nine cases (subjects 12-20) the treatment was preceded by the use of a larger levonorgestrel and estradiol impregnated CVR with outer diameter 58 mm. The subjects were advised to insert the CVR immediately after the cessation of menstrual bleeding. Thereafter, a 3-week in,l-week out schedule was followed. The treatment was planned to cover six cycles. All subjects inserted and removed the CVR by themselves, and kept records of bleeding as instructed. The subjects were controlled clinically during the treatment. This consisted of two vaginal smears for the evaluation of the local effect of the CVR. Bimanual examination, as well as blood transaminase and urinary glucose determinations were performed every three months. The subjective side-effects were registered by the subjects themselves. In three cases (subjects 1-3) peripheral blood samples were collected once or twice per week. No pretreatment cycle or recovery cycle samples were obtained. In subject 1 the blood samples were obtained throughout the treatment, and in subjects 2 and 3 during the first 90 days of treatment as well as during the sixth cycle. The blood was collected in heparinised tubes, centrifuged immediately, and the plasma stored at -2OOC until analysis.

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CONTRACEPTION

Radioiumunoassays The radioimmunoassay of levonorgestrel was performed as described earlier (4). The sensitivity of the assay was 25 pg/ml. The intraassay and interassay C.V. were 5.8% and 9.4%, respectively. The direct radioimmunoassays of estradiol and progesterone were performed as described earlier (5). The sensitivities of the assays were 5 pg/ml for estradiol and 25 pg/ml for progesterone. The intra-assay C.V. varied at different parts of the standard curve from 8.1% to 9.7% for estradiol, and from 6.4% to 7.8% for progesterone. The interassay C.V. varied from 11.7% to 16.6% for estradiol No corrections for the and from 12.9% to 14.1% for progesterone. extraction recoveries were done in the steroid radioimmunoassays. The radioisununoassays of plasma LH and FSH were performed as described earlier (6). The intra-assay C.V. were 9.3% and 2.4% for FSH and LH,respectively. The interassay C.V. was 14.7% for FSH and 14.2% for LH. In this laboratory the mean values (International Reference Preparation of Pituitary LH and FSH, code 69/104) of gonadotropins for the follicular and luteal phases of the normal menstrual cycle are 7.18+1.82 mIU/ml and 6.30+1.84 mIU/ml (mean + S.D., n = 23) for FSH, agd 4.07+1.16 mIU/ml a;d 3.21i1.28 mIU/ml(mean + S.D., n = 25) for LH, respectively. The midyycle gonadotropin-peaks are 13.7+3.93 mIU/ml (mean+ S.D. , n = 10) for FSH, and 26.6~6.74 mIU/ml (mean + S.D., n = 10) ?or LH.

RESULTS The treatment covered 116 cycles. The treatment was continued for six cycles, as planned, by eighteen subjects. Thus the continuation of the method at six months was 90 per cent. One subject (No. 20) discontinued the treatment after 3 cycles because of bleeding disturbances and the other (No. 7) after 5 cycles because of frequent passage of the urine (pollakiuria). The subjects experienced no difficulties in using the CVR. Five subjects removed the device occasionally prior to sexual intercourse. Bimanual examinations, vaginal smears and blood transaminase determinations revealed no pathological findings. Urinary glucose remained negative. No pregnancies occurred in this material. The subjects complained of the following side-effects: weight gain of 3-5 kg without feeling oedema (four subjects), disturbing oedema (one subject), headache during the first treatment cycle (one subject), and continuous moniliasis during the first three treatment cycles (one subject). In addition to these there was one spontaneous expulsion of the CVR, and pollakiurla was complained of throughout the treatment by one subject. In the latter case urinary infection was excluded three times during the treatment.

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CONTRACEPTION

Fig. 1 shows the bleeding patterns. In three cases (subjects 1, 12 and 16) the bleeding started regularly after every removal of the CVR. One of these (subject 12) continued to bleed for two days after the fourth and fifth insertion of the CVR. Nine subjects experienced quite regular bleedingz.but the bleeding or spotting started in some cycles l-5 days prior to the planned removal of the device. This kind of disturbance was generally well accepted by the subjects. Eight subjects experienced one or more breakthrough bleeding periods during the treatment cycles.. Out of these, six did not have withdrawal bleeding during one or more treatment-free periods. One of these women (subject 20) regarded the disturbance as so severe that she discontinued the treatment after 3 cycles.

BLEEDING PATTERNS

Fig. 1.

Bleeding patterns of 20 subjects during treatment with levonorgestrel-estradiol CVR with outer diameter of 50 mm. Open bars represent Zl-day treatment periods with a 7-day removal interval and hatched areas vaginal bleeding (full bar) or spotting (half bar).

The hormone profiles of subjects 1,2, and 3 are shown in Figs. 2-4. The release and absorption of levonorgestrel appeared fairly constant during the six-month period, as plasma levonorgestrel concentrations were similar in the first and sixth cycles of treatment. The plasma concentrations were generally around 1 ng/ml during the treatment periods. Plasma progesterone concentration was below 0.5 ng/ml in subject 1. Subject 2 demonstrated ovulatory progesterone

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JULY 1979VOL. 20 NO. 1

CONTRACEPTION levels at the end of the first treatment-free treek,at the end of the third, and during the sixth treatment periods. In subject 3 there was a progesterone value of 6 ng/ml during the fourth cycle in the last blood sample collected.

n DAYS

Fig. 2.

I

ia 20

m

ea ED

,

2D

m

0 20

/

20

0 ,

20

I

Subject 1. Plasma levels of progesterone (P), estradiol (E2), levonorgestrel (d-Ng) and gonadotropins (LH,FSH). Open bars represent treatment periods and hatched areas vaginal bleeding or spotting (half height of the area).

Plasma estradiol concentration was generally below 100 pg/ml throughout the sampling period. However, subject 2 had three estradiol peaks over 200 pg/ml. Two of the peaks were preovulatory as judged by the plasma progesterone concentrations. Plasma gonadotropin concentrations remained within normal fvllicular and luteal phase levels in subject 1, with the exception of two LH peaks. However, no change in plasma progesterone was observed following the peak. Quite normal cyclical changes in plasma LH and FSH concentrations were seen in subject 2. Subject 3 demonstrated low LH plasma levels during the first three treatment cycles.

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1979 VOL. 20NO.

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CONTRACEPTION C”R

16

g;“”

‘z”,;;

OUTER

DIAMETER

50 mm

Fig. 3.

(P), estradiol Subject 2. Plasma levels of progesterone (E2), levonorgestrel (d-Ng) and gonadotropins (LH,FSH). Open bars represent treatment periods and hatched areas vaginal bleeding or spotting (half height of the area).

Fig. 4.

(P), esrradiol Subject 3. Plasma levels of progesterone (E2), levonorgestrel (d-Ng) and gonadotropins (LH,FSH). Open bars represent treatment periods and hatched areas vaginal bleeding or spotting (half height of the area).

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DISCUSSION Contraceptive vaginal rings impregnated with levonorgestrel and estradiol have given promising results when used for contraceptive purposes (2,3). In those studies the outer diameter of the CVR has varied from 58 mm to 61 mm. Pituitary suppression has been mild and the recovery during the treatment-free period has been rapid (3). Although the method'has proved to be well tolerated. it was believed that a smaller ring would make the method more acceptable. In this work the use of levonorgestrel-estradiol CVRs with an outer diamater of 50 mm has been studied. Nine women had used the larger levonorgestrel-estradiol CVR for six months prior to the present treatment. Subjects experienced no differences in using different sized CVRs. The insertion of the smaller CVR was not regarded as being any easier. There was one spontaneous expulsion in a nulligravida woman. The expulsion took place when the subject was walking normally. The most probable reason for this was improper insertion. Only three of the twenty women experienced regular withdrawal bleeding during every treatment-free week. In 14 cases the bleeding began 1-5 days before planned removal of the CVR. This was the only disturbance in nine cases. Eight subjects experienced one or more breakthrough bleedings and six of these did not have a withdrawal bleeding. However, only one subject discontinued the treatment beIt appeared that the bleeding cause of bleeding disturbances. patterns were not as regular as observed with larger levonorgestrelestradiol CVRs (2,3). The plasma levonorgestrel concentrations produced by the 50-mm CVR were generally around 1 ng/ml, and concentrations with the larger CVR were usually between l-2 ng/ml or even higher (2,3). Dziuk and Cook (7) observed in their pioneer in vitro studies that the release of the steroid from polysiloxane tuGs= a solution of saline was related to the surface area and thickness of the polysiloxane tubes, not to the amount of steroid inside the tube. This offers an explanation for the differences observed in plasma levonorgestrel concentrations between CVRs of different size. Plasma gonadotropin concentrations were not suppressed in this material, with the exception of LH in one subject. We have found in our recent work with the 58-m CVR (3) that there is a mild pituitary suppression during the treatment and a rapid recovery during the treatment-free week. This can be regarded as a borderline situation in inhibition of ovulation. It can be concluded that a plasma levonorgestrel concentration around 1 ng/ml produced by the 5O-mm CVR is too low to inhibit ovulation in some individuals.

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CONTRACEPTION It seems that decreasing the diameter of the CVR has no positive effects. The subjects did not experience the use of a smaller ring to be any easier than the larger one. The decreased surface area resulted in lower release of steroids. Ovulations occurred and the control of the bleeding was less favourable than with the larger CVRs releasing higher amounts of levonorgestrel.

ACKNOWLEDGEMENTS This study was supported by the Population Council, New York, USA. Levonorgestrel antiserum was supplied by Schering AG, Berlin, Germany. The National Pituitary Agency of the National Institute of Arthritis, Metabolism and Digestive Diseases (NIAMDD) is acknowledged for supplying human LH, FSH and the antisera for these radioimmunoassays. The gonadotropin standard preparation was distributed by WHO. The antisera for steroid assays were donated by Dr. J.-P. Raynaud, Roussel Uclaf, Romainville, France and Dr. D. Apter, Department of Medical Chemistry, University of Helsinki and Schering AG, Berlin, Germany. The technical staff of the laboratory as well as the volunteers are also to be thanked.

REFERENCES 1. Mishell, D.R.,Jr., Talas, M., Parlow, A.F. and Moyer, D.L.: Contraception by means of a Silastic vaginal ring impregnated with medroxyprogesterone acetate. Am.J. Obstet. Gynecol. 107: 100-107, 1970.

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2.

Mishell, D.R.,Jr., Moore, D.E., Roy, S., Brenner, P.F. and Page, M.A.: Clinical performance and endocrine profiles with contraceptive vaginal rings containing a combination of estradiol and d-Norgestrel. Am. .J.Obstet. Gynecol. 130: 55-62, 1978.

3.

Toivonen, J., Llhteentiki, P. and Luukkainen, T.: Pituitary and gonadal function during the use of norgestrel-estradiol vaginal rings. Contraception 18: 201-211, 1978.

4.

Stanczyk, F.Z., Hiroi, M., Goebelsmann, U., Brenner, P.F., Lumkin, M.E. and Mishell, D.R.,Jr.: Radioimmunoassay of serum d-norgestrel in women following oral and intravaginal administration. Contraception 12: 279-295, 1975.

5.

LPhteedki, P.: A semiautomated radioimmunoassay technique employing a nine-channel pipetting and sample handling. Stand, J. Clin. Lab. Invest. 38: 1-4, 1978.

6.

Karonen, S.-L., Llhteentiki, P., Hohenthal, U., and Adlercreutz, H.: Evaluation of the double antibody-solid phase radioimmunoassay technique in plasma LH and FSH and urinary LH nmasurements. Stand. J. Clin. Lab. Invest. 38: 97-106, 1978.

7.

Dziuk, P.J. and Cook, B.: Passage of steroids through silicone rubber. Endocrinology 78: 208-211, 1966.

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