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At least 19 recordsLinked to original sources
PubMed1978

Clinical experience with implant contraception.

Subdermal implants of polysiloxane (Silastic) capsules containing a number of synthetic progestagens have been studied in clinical trials to determine their contraceptive effectiveness and acceptability. The steroids studied include norgestrienone (R2010), gestrigone (R2323), megestrol acetate, d-norgestrel, norethindrone, ST-1435, lynestrenol and R-1364. With some of these steroids, studies have been undertaken with a varying number of implanted capsules. The estimated duration of use varies from 6 months to 6 years depending on dose and release rate of the individual steroid. The results of these studies involving about 5000 women in 8 years, indicate in general a high rate of effectiveness, as well as acceptability. Continuation rates at one year were generally 80% or greater. Abnormal bleeding patterns are the major disadvantage. Studies with implatns containing a combination of estrogen and progestogen are being undertaken in an attempt to improve the bleeding pattern.

Contraceptive Agents, Female↗
PubMed1987

Norplant contraceptive implants: rods versus capsules.

Norplant contraceptive implants are silastic implants containing levonorgestrel. When placed subcutaneously in the medial aspect of the upper arm, they release low levels of levonorgestrel in a constant manner over an extended period of time. Comparative studies of two silastic rods versus six capsules containing levonorgestrel were studied in 250 subjects for 4,464 months of use. Only one pregnancy occurred during the study. Side effect patterns were similar in both groups; the major side effect being irregular uterine bleeding. The bleeding, however, was well tolerated by subjects in both groups and discontinuation rate was very low. The two-rod system offers the advantages of easier insertion technique and shorter insertion time as well as ease of removal as compared to the six-capsule system. Norplant contraceptive implants offer a highly effective means of contraception which is particularly suited for women who are concerned about failure and compliance with oral contraceptives. This type of contraception should become well accepted, not only in underdeveloped countries, but in developed countries as well.

Adolescent↗
PubMed1991

Phase II--clinical trial with biodegradable subdermal contraceptive implant Capronor (4.0-cm single implant). Indian Council of Medical Research Task Force on Hormonal Contraception.

The subdermal biodegradable contraceptive implant Capronor (4.0 cm) was implanted in 41 women to observe the efficacy and side effects. Only one pregnancy was reported at 10 months of use, and the life table continuation rate at 12 months was 82.2 per 100 users. No serious clinical side effects were reported during the study period. The menstrual pattern was disrupted during the first 3 months of implant use in two-thirds of the women which improved by the end of 12 months of use. The results of this Phase II study suggest that Capronor is a safe and effective long-acting contraceptive. These findings need to be confirmed in a Phase III clinical trial on a larger sample size.

Adolescent↗
PubMed1990

Attitudes towards contraceptive implants and injectables among present and former users in Singapore.

In a comparison of present and past users of contraceptive implants (Norplant) or injectables (DMPA) and discontinuers of Norplant or DMPA, information concerning the women's knowledge and perception of, and attitude to, implants and injectable contraceptives, was studied. The long duration of action (5 years) of implants was perceived positively by all groups as compared to the shorter 3-month duration of injectables, though this was seen as an advantage over the pill. It appears that the Norplant system has potential for wider use in Singapore in the future.

Adult↗
PubMed1992

Serum lipids, blood pressure, body weight, and serum chemistry in women using subcutaneous contraceptive implants releasing the progestin ST 1435.

OBJECTIVE: To study the changes in serum lipids, serum chemistry, blood pressure, and body weight in long-term users of subcutaneous contraceptive implants releasing the progestin ST 1435. METHODS: The study was done in the outpatient clinic of the City Maternity Hospital, Helsinki, Finland. Subdermal implants releasing the progestin ST 1435 were inserted in 30 women for 2 years of use. Healthy women aged 19-35 used the implants for contraception. Measurements of body weight and blood pressure were made and blood samples for lipid analysis (total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides) and serum chemistry were taken before insertion of the implants and every 6 months thereafter until removal. Results are reported for 30 subjects after 6 months of use, 25 subjects after 12 months, 13 after 18 months, and 12 after 24 months. RESULTS: Blood pressure and serum chemistry, ie, liver enzymes and electrolytes, remained unchanged. Slight weight gain occurred, but was not statistically significant. No statistically significant changes were found in lipids or lipid ratios when comparing the values during use of the implant with the pre-treatment values. CONCLUSIONS: The progestin ST 1435, used parenterally for contraception or progestin therapy, had no adverse effects on serum lipids, blood pressure, or body weight, which are known to be risk factors for coronary artery disease. The steroid had no effects on serum chemistry determinations in long-term use.

Adult↗
PubMed1988

Serum lipid profile in women using levonorgestrel contraceptive implant, Norplant-2.

Cholesterol content of major lipoprotein fractions along with total cholesterol (Tc) and triglyceride (Tg) were measured in 65 samples from 35 women using levonorgestrel contraceptive implant, Norplant-2 from the third month of implantation until the end of second year along with twenty-five healthy controls. There were significant decreases in all the fractional lipid values, Tc and Tg, up to the sixth month followed by a gradual rise of all lipid parameters except HDLc which remained much below the control level. Interestingly, VLDLc exhibited a significant rise at the end of the second year.

Adult↗
PubMedDate not supplied

Insertion and removal of Norplant contraceptive implants by physicians and nonphysicians in an Indonesian clinic.

This paper reports on a study in which the performances of physicians were compared to those of nonphysician health personnel in inserting and removing NORPLANT subdermal contraceptive implants. The study was conducted in Raden Saleh Clinic at the University of Indonesia, Jakarta, from September 1982 to August 1984. In a group of 828 women who accepted NORPLANT 285 insertions were performed by physicians and 543 by nonphysician health personnel. During the study period, 122 removals were performed (43 by physicians and 79 by nonphysicians). This small proportion of removals reflects the high continuation rate for NORPLANT. There was no significant difference between the two groups of acceptors regarding age, parity, education, or side effects. The average insertion times were 7.6 minutes for the physician group and 7.4 minutes for the nonphysician group (p greater than 0.1). The average removal times were 21.7 minutes for physicians and 21.8 minutes for nonphysicians (p greater than 0.9). Complications during and following insertion and removal were minimal for both groups, and no significant differences were found. It was concluded that nonphysician health personnel are qualified to administer the NORPLANT contraceptive implants.

Adult↗
PubMed1992

Injectable and implantable contraceptives.

In December 1990, the Food and Drug Administration approved Norplant (Wyeth-Ayerst, Radnor, PA) for general US use. This approval comes during a time period when the number of contraceptors relying on sterilization has risen, echoing known dissatisfaction with other reversible methods. During the past year, data have been presented that refute concern that Norplant may be an abortifacient. Continued estradiol production with development of follicles and ovulation in regularly menstruating women was documented. Ovulatory dysfunction among Norplant users, despite follicular development, was also detailed. Changes in carbohydrate metabolism were confirmed to be clinically insignificant. International development of biodegradable and non-biodegradable implants and 1, 3, or 6 months injectables continues. These injectable and implantable contraceptives promise diversity in contraceptive options to match diversity in contraceptive need and life style.

Capsules↗
PubMed1992

Evaluation of a 1-year levonorgestrel-releasing contraceptive implant: side effects, release rates, and biodegradability.

OBJECTIVE: To determine the release rates, effects on ovulation, and side effects of two lengths of a biodegradable, subdermal contraceptive implant containing levonorgestrel in a caprolactone capsule. DESIGN: Phase II randomized clinical trial. SETTING: Public family planning clinic at an urban general hospital. PARTICIPANTS: Forty-eight healthy, parous, ovulating volunteers. INTERVENTION: Subjects were randomly assigned either a 2.5- or a 4.0-cm contraceptive capsule that was worn under the skin of the upper arm for 1 year if not removed earlier for other reasons. MAIN OUTCOME MEASURES: Serum concentrations of levonorgestrel, progesterone, estradiol, and lipoproteins were measured as were metabolic parameters. Vaginal bleeding and other side effects were recorded. After implant removal, remaining levonorgestrel, capsule viscosity, and molecular weight were measured. RESULTS: The 4-cm implant provided serum concentrations of levonorgestrel ranging from 0.65 ng/mL shortly after insertion to 0.20 ng/mL at 12 months, but the 2.5-cm implant resulted in levels too low for contraception. The 4-cm implant suppressed ovulation in approximately 80% of cycles over 1 year of use, but the 2.5-cm implant failed to suppress ovulation. The implants were rapidly and easily inserted and removed. They retained structural integrity through 1 year of use. Of 48 subjects, 32 had abnormal bleeding patterns; the mean number of days of bleeding per month was 7 with 23 days between episodes. Women using capronor maintained normal metabolic parameters except that low-density lipoprotein decreased slightly. CONCLUSIONS: The 4.0-cm implant is a promising contraceptive. There were no important metabolic effects, but there were bothersome minor side effects typical of progestin-only contraception.

Abdominal Pain↗
PubMed1991

Subdermal progestin implant contraception.

Sustained-release progestin contraceptives are a new approach to meeting a worldwide need for more effective and acceptable birth control. These contraceptive systems provide low, stable levels of synthetic progestins for periods of months to several years. Unlike earlier injectable and oral contraceptives, they do not cause peaks in progestin levels beyond those required for effective contraception, nor do they employ estrogens. For these reasons, sustained-release progestin systems are without some of the health risks attributed to birth control pills, and they are more effective, as well as easy to use, and completely reversible. They share common side effects, the most frequent of which is irregular menstrual bleeding caused by the erratic shedding of hypotrophic endometrium. Despite this and other minor side effects, most users find the sustained-release systems acceptable alternatives to other methods of contraception. Permanent or biodegradable subdermal implants, injections, intrauterine and intracervical devices, and vaginal rings are all employed as delivery systems for contraceptive progestins. The Norplant (Wyeth Ayerst, Radnor, PA) system, consisting of six silastic tubes filled with levonorgestrel and implanted under the skin, was recently approved by the US Food and Drug Administration and is already used by more than a half million women worldwide. The other sustained-release systems are in various stages of development, at least several years away from general use. When these new methods complete clinical trials, women will be able to choose from among implants, injections, or pellets with various durations of action, all providing convenient, highly effective contraception with low risk to health.

Biodegradation, Environmental↗
PubMed1989

Clinical evaluation of the Capronor contraceptive implant: preliminary report.

Capronor, a single-capsule, biodegradable, subdermal contraceptive that releases levonorgestrel over a 12- to 18-month period, has been evaluated in 48 healthy women, ages 18 to 40 years. Sixteen participants received a 2.5 cm capsule (12 mg of levonorgestrel), and 32 received a 4.0 cm capsule (21.6 mg of levonorgestrel). Serum levonorgestrel levels were significantly lower in the 2.5 cm group. Ovulation occurred in all cycles in the 2.5 cm group and in 26.3% of cycles in the 4.0 cm group. Levonorgestrel levels with the shorter capsule were too low for reliable contraception in all users, and 4 cm may be a minimal functional length. Bleeding patterns were regular in most women who ovulated and irregular in most remaining subjects. It is assumed that changes in cervical mucus and the endometrium contributed to effective contraception despite the frequency of ovulation.

Administration, Cutaneous↗
PubMedDate not supplied

Characteristics and attitudes of early contraceptive implant acceptors in Texas.

In 1991, shortly after Norplant became available in the United States, 678 women who had received the implant from 17 providers in Texas were surveyed. Forty-five percent of these women were under 21 years old. The majority (56%) had tried the implant because they were dissatisfied with their previous contraceptive method. Forty-four percent of the sample indicated that the implant was one of the first contraceptive methods they had used and that they had only recently decided to prevent unplanned pregnancy. The average number of children per woman was 1.2, and one-third of the sample had had at least one abortion. While 37% of the women said they wanted no more children, 63% said they were using the implant as a spacing method. The reasons for choosing the implant and concerns about it varied according to the user's age, educational level and race or ethnic group.

Adolescent↗
PubMed1987

Ovulation detection following removal of levonorgestrel subdermal contraceptive implants.

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

Adult↗
PubMed1987

Pregnancy after removal of Norplant implants contraceptive.

Many concerns have been expressed regarding the introduction of a new contraceptive method into family planning programmes. One of the concerns is the return of fertility after discontinuing the method. To evaluate the subsequent fertility status of the Indonesian women after removal of Norplant, a prospective longitudinal study was undertaken in Klinik Radeb Saleh, Jakarta. Fifty-one women whose Norplant were removed because of their wish to become pregnant were followed-up for a period of two years or until pregnancy occurred, whichever was earlier. Two groups of women who had Lippes C IUD removed or discontinued the use of DMPA for planning pregnancy served as control and were followed-up for equal length of time. The cumulative conception rate for ex-Norplant users, ex-IUD users and ex-DMPA users at one year was 76.5, 74.7 and 70.2 per 100 women, respectively. There was no significant difference between the groups (p greater than 0.05). The present study, along with other studies, indicate that the prolonged use of Norplant do not impair the return of fertility.

Adult↗
PubMed1987

The interaction between sex hormone binding globulin and levonorgestrel released from Norplant, an implantable contraceptive.

Two-hundred-and-eighty Indonesian women were provided with Norplant, a levonorgestrel-releasing implant. At various time intervals, up to 5 years after Norplant insertion, levonorgestrel and sex hormone binding globulin (SHBG) were assayed in blood plasma. After an initial burst of approximately 7 nmol/l, the levels of levonorgestrel rapidly decreased during the first month. The decrease continued to a nadir (1.1 nmol/l) which was reached 10 months later. The decrease was followed by an increase to a broad peak of 1.5 nmol/l which was reached 2 years after insertion. Thereafter, a slow-decrease at a rate of approximately 18 pmol/month was seen. SHBG levels decreased significantly already 1 week after insertion. A nadir of levels (25 nmol/l) was reached 3 months later. The levels increased slowly again and remained constant (32 nmol/l) from about 15 months to 5 years. During the entire period of study highly significant correlations of levonorgestrel with SHBG were seen. In another group of 25 women the levels of levonorgestrel and SHBG were studied before and one week after insertion of Norplant. A significant correlation (r = 0.77) was found between the preinsertion levels of SHBG and postinsertion levels of levonorgestrel.

Adult↗
PubMed1990

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

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

Contraceptive Agents, Female↗
PubMed1986

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

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

Breast Feeding↗