Many reports have indicated that oral contraceptives can increase the incidence of thromboembolic disorders. Norplant, an implant contraceptive containing levonorgestrel, has been developed recently. The aim of this study is to observe the effect of Norplant on some hemostatic parameters. The subjects in this study were divided into 5 groups. Group 1 (control) consisted of 25 female blood donors. Group 2 (N = 25), group 3 (n = 25), group 4 (n = 17) and group 5 (N = 20) consisted of subjects who had been using Norplant for 2, 3, 4, and 5 years, respectively. Prothrombin time, activated partial thromboplastin time, fibrinogen level, assay of F VII and X, antithrombin III activity, plasminogen activity, alpha 2-plasmin inhibitor activity and platelet aggregation test were done in all subjects. Our results showed that there was a significant difference (p < 0.05) on platelet aggregation induced by 10 microM of ADP between the control group and Norplant users for more than 2 years, while the other parameters did not differ significantly. It is concluded that 5 years users of Norplant did not alter blood coagulability, but increased platelet response to 10 microM of ADP.

US women attending family planning clinics in Texas, were surveyed to determine which characteristics, experiences, behavior and specific needs were associated with the selection of the contraceptive Norplant. Race, ethnic origin, age and education were unrelated to choice of method. Increased numbers of previous pregnancies, familiarity with the method, dissatisfaction with previous methods, and sources of information about Norplant were associated with its selection. There was significant variation among the clinics in the proportion of patients to which they dispensed the method. Therefore, clinic selection may have influenced the outcomes of contraceptive decisions.

This report describe the long-term follow-up of 376 women who received Norplant implants in the period october 1974 through may 1979. One-hundred-and-ten subjects received replacement implants after variable lengths of use of the first set. The average levonorgestrel plasma levels declined steadily through eight years of use of Norplant capsules (r = -937). Values were 0.35 ng/ml, 0.29 ng/ml and 0.22 ng/ml at treatment years 1, 5 and 8, respectively. Levonorgestrel plasma levels after replacement with a second set of implants were similar to those observed after the first insertion, either when placed in the same site as the first set or in a different area. The levonorgestrel half-life after implant removal was 42 +/- 16 h (X +/- S.E.) and only trace amounts are detected after 96 h. Nineteen pregnancies occurred during 18,530 woman-months of use of the first set of implants, eleven of them during years 6 through 8 of treatment. The Pearl Index for the first years of Norplant implants use was 0.63. No pregnancy has occurred in 5.020 woman-months observed during treatment with a second set of capsules. Fifty-six women (14.9%) out of 376 acceptors of the first implant and 12 (10.9%) out of 110 acceptors of the replacement implants were terminated for other medical reasons, mainly side effects commonly associated with hormonal contraception. Removals for bleeding problems occurred in 5.6% and 3.6% of the acceptors of the first and second implant, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Subdermal implantable contraception has been the most important addition to contraceptive technology in the past 2 decades. The Norplant system is only the first of a new family of long acting methods of high effectiveness, high acceptability, and prompt reversibility. The main advantage of the second generation implant systems, to be available soon, is the reduction in the number of implants, which greatly facilitates insertion and removal. However, great improvement in bleeding control is not to be expected. Large and carefully designed epidemiological studies have contributed to clear the main objections to the US Food and Drug Administration (FDA) approval of depot medroxyprogesterone acetate (DMPA) as an injectable contraceptive. New progestin-only, long acting injectables are being tested, but significant improvements over existing methods are difficult to foresee, although every alternative is welcome. Monthly combined injectables have been in great demand, at least in China and Latin America, because of better bleeding control. Improved combined monthly injectables, less estrogenic and more progestin dominated, have been developed and are being introduced in several countries and should soon replace the old monthly injectables. Contraceptive implants and injectables have shown to be an important addition to the contraceptive options available to women throughout both the developing and developed world.

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

In a phase III multicentre clinical trial, the subdermal implant NorplantR-2 was studied for its clinical use effectiveness, safety and bleeding pattern. A total of 1466 healthy volunteers, with no contraindication to steroid use, were observed for 29,669 woman-months of use. One method failure was reported at 18 months of NorplantR-2 use. The method was associated with altered menstrual pattern with a trend towards reduced blood loss. The continuation rates were 88.1 and 73.5 per 100 users at 12 and 24 months of use, respectively. Menstrual disturbance, mainly prolonged bleeding, accounted for the majority of the discontinuations. Removal of NorplantR-2 due to local infection was rare (0.4 per 100 users at 24 months). In similar clinical trial conditions, the continuation rate with NorplantR-2 is significantly higher than those observed with LNG IUD and injectable contraceptives, norethisterone oenanthate 200 mg given every 60 +/- 5 days, and is comparable to that of CuT 200 IUD.

Subdermally implanted slow-release levonorgestrel (Norplant), a widely used effective contraceptive, has a high rate of discontinuation due to unacceptable menstrual bleeding disturbances. Endothelin (ET), a potent vasoconstrictor, varies across the menstrual cycle in normal endometrium. It has been proposed that ET has a potential paracrine role in the regulation of uterine blood flow. Neutral endopeptidase (NEP), a membrane-bound ecto-enzyme, can inactivate ET and is localized principally in endometrial stroma. We have compared the immuno-localization of ET and NEP in endometrial biopsies from Indonesian women using Norplant with normal controls. Differences were observed in the glandular and luminal epithelium of Norplant-treated subjects, where ET immunostaining was low while NEP immunoreactivity was increased. The latter may represent a local increase in enzyme activity, potentially explaining the reduced ET immunoreactivity. There was no correlation of ET immuno-reactivity with the duration of implant use or total number of bleeding days. The marked differences in the ET immunostaining pattern in Norplant users, with their increased risk of abnormal uterine bleeding, suggest that ET may be important in controlling menstrual bleeding. Whether endometrial epithelial cell ET has a role as a mitogen in endometrial repair and regeneration, or as a vasoconstrictor important in the cessation of bleeding following menstruation, remains to be determined.

OBJECTIVE

To determine if fertilization occurs unnoticed among Norplant users who are ovulatory.

METHODS

Serial blood samples were obtained during 1 month from sexually active Norplant users experiencing regular menstrual bleeding patterns and a control group of noncontracepting women trying to conceive. The sequential blood samples were assayed for the presence of human chorionic gonadotropin (hCG).

METHODS

All samples were obtained from women receiving contraceptive service and health care at the Center for Research and Services in Human Reproduction and Contraception, Santo Domingo, The Dominican Republic. Assays for hCG were performed at the Department of Biomedical Sciences, University of Tampere, Finland.

METHODS

A total of 32 women using Norplant implants were enrolled in the treatment group, and 20 women of proven fertility who were attempting to conceive served as a control group.

METHODS

Duration of Norplant use was as follows: 4 in the 2nd year of use, 13 in the 3rd year, 11 in the 4th year, 3 in the 5th year, and 1 in the 7th year.

METHODS

The determination of pregnancy was based on the presence of hCG in the luteal phase, using a sensitive and specific immunoenzymatic assay that can detect dimeric hCG as early as 7 days after ovulation.

RESULTS

Nine pregnancies were detected. All were in the control group trying to conceive. Six of these advanced to clinical pregnancies, and three did not proceed beyond the next expected menses. None of the Norplant users had evidence of hCG production, whether the observed cycles were anovulatory or ovulatory. The probability of finding no pregnancies in the ovulatory months at risk among Norplant users is between 1 in 50 and 1 in 150,000. The null hypothesis that Norplant users conceive at a natural rate can be rejected at the 0.05 level.

CONCLUSIONS

Interruption of early pregnancy (menstrual abortion) does not play a role in the mechanism of action of Norplant contraceptive implants.

During an ongoing study of a pre-introduction trial of Norplant in Zimbabwe, 197 women had the subdermal implant of six capsules containing levonorgestrel inserted between June and December 1991, at Parirenyatwa, Harare Hospital and Spilhaus. Acceptability and efficacy were high and no significant side effects had been observed. Three implants were removed due to local infection. Our initial experience indicates that the Norplant continuation rate is much higher than for any other reversible method of contraception and it is highly acceptable as a long term contraceptive.

This article examines the beliefs about Depo-Provera held by three groups of contraceptors utilizing urban family planning clinics in the United States (n = 836). Patients choosing Depo-Provera, oral contraceptives, and Norplant were asked about their beliefs regarding Depo-Provera in the following four domains: effectiveness in preventing pregnancy, convenience, side-effects, and risk to health; and also for their perceptions regarding the physical discomfort and cost associated with the method. Findings reveal that patients choosing the pill and Norplant give Depo-Provera significantly lower ratings for both convenience and effectiveness than do Depo-Provera acceptors. Given the documented effectiveness of Depo-Provera, this is a potential cause for concern. Moreover, Norplant and pill choosers are most likely to hold inaccurate beliefs regarding both the cost of Depo-Provera, and certain side-effects associated with its use. Although more than half of all patients believe the Depo-Provera would cause menstrual changes and weight gain, it is noteworthy that the proportions are not higher, given their known association with the method. Knowledge about the likelihood of these side-effects is essential, particularly for those choosing Depo-Provera. Implications for physicians, counselors, and other family planning professionals are discussed.

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

Combined pills have known adverse effects on liver function. Progesterone based contraceptives are thought to be safer in this regard. The effect of Norplant, a levonorgestrel contraceptive implant, on liver function was evaluated in 149 Bangladeshi women of reproductive age in this study. Liver function tests and ultrasonography of hepato-biliary system were done before and after the implantation. The patients were followed upto two years. There were non-significant transient rise of serum bilirubin and slight enlargement of liver during the first year. There was no significant change in the levels of AST, ALT, alkaline phosphatase, total protein, albumin-globulin ratio and prothrombin time. The results suggest that Norplant has no adverse effect on liver function.