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At least 127 records · Page 7Linked to original sources
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↗
PubMed2005

A prospective study of the forearm bone density of users of etonorgestrel- and levonorgestrel-releasing contraceptive implants.

BACKGROUND: The aim of the study was to compare bone mineral density (BMD) before insertion and at 18 months of use of etonorgestrel- and levonorgestrel-releasing contraceptive implants. METHODS: One hundred and eleven women, 19-43 years of age, were randomly allocated to two groups: 56 to etonorgestrel and 55 to levonorgestrel. BMD was evaluated at the midshaft of the ulna and at the distal radius of the non-dominant forearm using dual-energy X-ray absorptiometry before insertion and at 18 months of use. RESULTS: There was no difference in baseline demographic or anthropometric characteristics, or in BMD of users of either model of implant. BMD was significantly lower at 18 months of use at the midshaft of the ulna in both groups of users. However, no difference was found at the distal radius. Multiple linear regression analysis showed that the variables associated with BMD at 18 months of use in both implant groups were baseline BMD, body mass index (BMI) and difference in BMI (0 versus 18 months of use). CONCLUSIONS: Women of 19-43 years of age using either one of the implants showed lower BMD at 18 months of use at the midshaft of the ulna, however, without a difference at the distal radius.

Absorptiometry, Photon↗
PubMed2005

Contraceptive implants.

In response to the need of some women for long-acting, effective and safe contraceptives, the scientific community developed non-biodegradable progestational subdermal implants that act by making the cervical mucus viscous, with ovulation inhibition and thinning of the endometrial lining. The contraceptive protection is within 24 hours and the cumulative failure rate is low. Contraceptive implants require little or no motivation following adequate counselling. In current use are multirod implants (Norplant I and Norplant II Jadelle) and single rod implant (Implanon and Uniplant). Although menstrual symptoms associated with progestational regimens are the major compliance and acceptability factors within the first year of use, menstrual disturbance generally improves. Continuation rates for implant use are high among those who have had adequate pre-insertion counselling because the perceived advantages greatly outweigh the nuisance effects. Other side effects of implants are similar to those observed with hormonal pills--headache, weight changes, mood swings and abdominal bloating. Training of physicians and nurses in the art of insertion and removal techniques is a pre-requisite for a successful implant programme. This should also be backed by integration of implants into the national commodity logistics systems to ensure adequate local budgetary provision for contraceptive implant procurement rather than reliance on donor supply.

Adolescent↗
PubMed2003

[A randomized study comparing the efficacy and bleeding pattern of Implanon and Norplant hormonal contraceptive implant].

OBJECTIVE: To compare the contraceptive efficacy, tolerability and bleeding patterns of Implanon and Norplant. METHODS: One hundred healthy female volunteers received either Implanon (75 cases) or Norplant (25 cases) for 4 years, followed up with complain, bleeding patterns, hemoglobin, blood pressure, weight. Record the time of insert and remove. RESULTS: There were no pregnancies during the study. Per 90-day reference period, the average number of bleeding-spotting days with Implanon decreased from 33 day in the first period to 21 day in the last year, and Norplant decreased from 31 day to 20 day. The average bleeding number of times was 2.25 of Implanon and 2.99 of Norplant per reference period (P < 0.05). The mean insert time was 11 second of Implanon and 103 second of Norplant. The mean remove time was 27 second of Implanon and 102 second of Norplant (P < 0.001). CONCLUSION: Both contraceptive systems demonstrated excellent contraceptive efficacy and were well tolerated. Because of its single-rod design, Implanon was significantly quicker to insert and remove than the multiple-capsule system.

Adult↗
PubMed1999

Study of the effects of the implantable contraceptive Norplant on lipid and lipoprotein metabolism. UN Development Programme/UN Population Fund/WHO/World Bank, Special Programme of Research, Development and Research Training in Human Reproduction, Task Force on Long-Acting Systemic Agents for Fertility Regulation.

A 2-year longitudinal study was undertaken to investigate the effects of the implantable contraceptive Norplant on lipid and lipoprotein metabolism. A group of 177 Norplant implants acceptors was recruited in five centers (Bangkok, Jakarta, Mexico City, Singapore, and Stockholm) and monitored during one baseline menstrual cycle and 3, 5, 11, 16, and 22 months after implant insertion. They were compared with a group of 174 copper intrauterine (IUD) device users who had blood sampling performed at comparable time points. Lipid changes were greatest 3 months after implant insertion and a slow reversal of these trends towards baseline was observed during the next 19 months. The main changes observed at 3 months were a 10% drop in total cholesterol, and an 11% drop in high-density lipoprotein (HDL)-cholesterol and apolipoprotein AI levels, together with a 19% decline in serum triglycerides. Variations in low-density lipoprotein (LDL)-cholesterol and apolipoprotein B levels were not significantly different from those observed in the group of IUD users. There was consistency in these findings between centers in that the changes were in the same direction but of different magnitude in different centers. It is concluded that lipid changes induced by Norplant implants will probably not affect the risk of atherosclerotic disease in women who use this contraceptive method.

Adolescent↗
PubMed2000

Once a month administration of mifepristone improves bleeding patterns in women using subdermal contraceptive implants releasing levonorgestrel.

It has been suggested that the administration of an anti-progesterone might improve bleeding patterns in women with irregular bleeding while using low-dose progestin-only contraception. We report the findings of a double-blind, randomized, placebo-controlled trial of mifepristone 50 mg taken once every 4 weeks in 100 Chinese women (50 subjects and 50 controls) complaining of frequent and irregular bleeding while using a levonorgestrel-releasing subdermal contraceptive implant. In all women, regardless of treatment, the frequency of bleeding decreased significantly over 360 days of observation. Women recorded significantly shorter episodes of bleeding (P: < 0.0002) during mifepristone treatment than during the 90 days before treatment started. In contrast, the duration of bleeding episodes fell more gradually in placebo-treated controls. Women using mifepristone were more likely to find treatment acceptable than women receiving a placebo tablet (P: < 0.01). Despite concern that anti-progestogenic effects may jeopardize contraception, there were no pregnancies. This approach may offer a useful strategy to improve continuation rates by alleviating unwanted side-effects until bleeding patterns improve spontaneously with time.

Adolescent↗
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↗
PubMed1998

Twenty-four month comparison of apolipoproteins A-1, A-II and B in contraceptive implant users (Norplant and Implanon) in Birmingham, United Kingdom.

A 2-year prospective, randomized study of 60 implant users was performed to evaluate fasting serial serum apolipoprotein A-I, A-II, and B levels before insertion and every 3 months in users of two contraceptive implants releasing levonorgestrel (Norplant) and 3-ketodesogestrel/etonogestrel (Implanon) in Birmingham, United Kingdom. All changes in serum apolipoprotein concentrations, irrespective of an increase or decrease, were smaller than one standard deviation of the mean concentration at baseline and did not exceed the normal range for the laboratory, thus implying no evidence of an increased risk of coronary heart disease.

Adolescent↗
PubMed2004

[Two patients with a non-palpable, subcutaneously implanted contraceptive].

Two women, 33 and 31 years of age, were referred to a surgeon for the removal of a previously implanted hormonal contraceptive after the general practitioner had attempted this without success. However, no foreign body could be detected in either patient by surgery, echography and MRI and by X-ray, echography and MRI, respectively. They were then referred to a gynaecologist. In the first patient, a low level of etonogestrel confirmed that there was no contraceptive in her body. Subcutaneous contraceptives are sometimes implanted incorrectly. If the rod is not palpable at the site of insertion, then the etonogestrel level should be determined first of all. If the hormone level indicates that a rod is indeed present, then echography or MRI may be considered to localise it before resorting to surgical exploration. Many problems can be prevented by proper implantation.

Adult↗
PubMed2000

Bone mineral density during long-term use of the progestagen contraceptive implant Implanon compared to a non-hormonal method of contraception.

An open, prospective, comparative study was done in healthy women, aged between 18 and 40 years, to study the effects of long-term etonogestrel treatment on bone mineral density (BMD). The control group used a non-hormone-medicated intrauterine device (IUD). The BMD was measured using a dual energy X-ray absorptiometry instrument. Measurements included the lumbar spine (L(2)-L(4)), the proximal femur (femoral neck, Ward's triangle, trochanter) and distal radius. The period of treatment was 2 years and 44 women in the Implanon group and 29 in the IUD group provided data. Groups were comparable at baseline with respect to age, weight, body mass index, BMD and 17beta-oestradiol status. Changes from baseline in BMD in the Implanon group were not essentially different from those in the IUD group. There was no relationship between 17beta-oestradiol concentrations and changes in BMD in this study population. The results of the present study indicate that Implanon((R)) can safely be used in young women who have not yet achieved their peak bone mass.

Absorptiometry, Photon↗
PubMed1997

Biodegradable norethindrone (NET:cholesterol) contraceptive implants: phase II-A: a clinical study in women.

Safety, contraceptive efficacy and biodegradability of subdermal norethindrone (NET)-cholesterol implants (Anuelle) were investigated in 19 healthy, sexually active women. Mean serum NET levels in women with four and five pellets, containing 174 mg and 266.5 mg NET, showed a "burst-effect" of 3.17 and 3.71 ng/ml, respectively, within 24 h post implantation. Subsequently, for the four- and five-pellet groups, respectively, the levels declined from 0.75 to 0.40 ng/ml and 1.05 to 0.61 ng/ml during the months 12-15, from 0.40 to 0.11 ng/ml and 0.61 to 0.25 ng/ml up to month 36. The serum NET levels were undetectable at 36 months and beyond, indicating complete biodegradability of NET pellets. Serum E2 levels remained within normal limits (> 50 pg/ml), whereas serum P indicated anovulatory cycles in 78% of the four-pellet group and 99% of the five-pellet group. FSH and LH levels were subnormal and acyclic. Plasma lipids showed reduced total and LDL cholesterol and triglycerides. HDL cholesterol remained unchanged. Drug-related adverse effects were essentially limited to irregular bleeding. There were no pregnancies in either group.

Adolescent↗