INTRODUCTION:

Contraception (birth control) prevents pregnancy by interfering with the normal process of ovulation, fertilization, and implantation. In response to the need of some women for long-acting, effective and safe contraceptive, the scientific community developed non-biodegradable progestational subdermal implants that act by making cervical mucus viscous, with ovulation inhibition and thinning of endometrial lining ^1. The contraceptive protection is 24 hours and the cumulative failure rate is low. Contraceptive implants are long-acting, effective method of contraception. It is over 99% reliable in preventing pregnancy, which means that less than one in 100 women who use the implant will become pregnant each year. The implant work by slowly releasing a hormone called progestogen into your body. It can be started at any time during your menstrual cycle, as long as you and your doctor are reasonably sure that you are not pregnant ^2.

NEED OF CONTRACEPTION:

Every month, a woman's body begins the process that can potentially lead to pregnancy. An egg (ovum) matures, the mucus that is secreted by the cervix (a cylindrical-shaped organ at the lower end of the uterus) changes to be more inviting to sperm, and the lining of the uterus grows in preparation for receiving a fertilized egg.

Any woman who wants to prevent pregnancy must use a reliable form of birth control ³. HIV-positive women have particular needs for contraception to avoid unwanted pregnancy, to protect their own health and to eliminate the risk of transmitting HIV to an infant and to control population ^4.

Different types of contraception methods^5:

1) Permanent Methods. The two permanent surgical methods of contraception are 99 to 99.5 percent effective. They do not prevent RTIs, or HIV transmission, and they both involve a risk of infection or bleeding. In male sterilization, or vasectomy, the vas deferens (the tubes that carry the sperm from the testicles to the penis) are blocked or cut. Female sterilization, or tubal ligation, is a surgical procedure in which a woman's fallopian tubes are cut, burnt, or blocked to prevent sperm from reaching and fertilizing the egg.

2) Long-Acting Methods. None of the long-acting methods protect against RTIs or HIV transmission. IUDs, implants, and injections are 99 percent effective. Oral contraceptive pills are theoretically 99 percent effective, but pregnancies do occur if pills are missed or not taken on time.

a) IUD:

An intrauterine device (IUD) is most often a nonhormonal method of contraception. The IUD is a small plastic or plastic and copper device placed inside a woman's uterus by a trained health care provider, and it protects against pregnancy for up to twelve years. The IUD may increase the risk of RTIs for women who have more than one partner. Side effects include increased cramping and bleeding during monthly periods. Some IUDs contain a hormone (progesterone) to increase their pregnancy protection while decreasing the risk of heavy bleeding. All of the other long-acting contraceptive methods are hormonal method.

b) Oral Contraceptive Pill:

"The Pill" was introduced in the United States in the 1960s. It contains one or two hormones (either estrogen and progesterone together, or progesterone alone) that prevent ovulation and create a hostile environment for sperm. Although there was originally controversy over the health risks of the pill, it is now considered to be relatively safe for nonsmokers. In fact, it may protect against cancer of the ovaries and uterus. Side effects include nausea, breast tenderness, spotting, weight gain, mood changes, and headaches. Women who smoke should not take the pill as it may cause fatal blood clots. The pill's effectiveness is 99.5 percent if used perfectly, but 95 percent in real use.

c) Contraceptive Implants:

Manufactured under the brand name Norplant®, contraceptive implants are silicone rods containing the hormone progesterone. Six of these matchstick-sized rods are placed under the skin of a woman's upper arm. The progesterone is released over time, and the implants remain effective for five years. While the effectiveness of implants is 99 percent, side effects include irregular monthly periods, spotting, acne, headaches, weight gain, and hair loss. Newer implants use one or two rods and may contain more than one hormone.

d) Hormonal Injections:

Progesterone injections are given every two to three months, while those containing estrogen and progesterone are administered monthly. Injections work by stopping ovulation and making the cervical mucus hostile to sperm. Side effects include irregular periods, spotting, weight gain, headaches, depression, loss of libido, and hair loss.

3) Short-acting methods:

Somewhat less effective than long-lasting methods, these contraceptives have fewer side effects. They are primarily physical or chemical barriers that also prevent or decrease the chances of transmitting RTIs and HIV.

a) Male Condom.

This type of condom consists of a latex or animal intestine sheath that is placed over the erect penis before intercourse. Effectiveness is about 86 percent, as condoms can tear or slip off. Some people are allergic to latex and cannot use this type of condom. Latex condoms protect against RTIs and HIV infection, while those made from animal intestine do not.

b) Female Condom.

The thin, female condom is plastic, tunnel-shaped device that is closed on one end. The closed end is placed over the cervix. It protects against both RTIs and pregnancy. One advantage of the female condom is that is it controlled by the woman. This feature is particularly important in a relationship where the woman cannot negotiate for safe sex. There are no medical limitations or side effects. At 80 percent effectiveness, the female condom is slightly less effective than the male condom.

c) Spermicides and Vaginal Barriers.

Spermicides are chemicals that kill sperm or immobilize them. They come in many forms, including foaming tablets or suppositories, melting suppositories, foam, melting film, creams, and jellies. All are placed in the vagina prior to intercourse. Some women have allergic reactions to spermicides. Effectiveness is 80 percent. Spermicides can be used alone or in combination with condoms or vaginal barriers. These devices may also protect against RTIs and HIV, but their effectiveness in this regard is as of yet unknown.

Vaginal barriers (diaphragm, cervical cap, and sponge) are inserted in the vagina before inter-course and must be used with spermicides to be effective. A diaphragm is a soft rubber cup that covers the cervix, a cervical cap is a smaller rubber cup that fits right over the cervix, and a contraceptive sponge is a sponge impregnated with spermicide.

d) Emergency Contraceptive Pills.

Emergency Contraceptive Pills Also known as morning-after pills or post-coital pills, these are either estrogen and progesterone or progesterone-only pills that are taken within seventy-two hours of unprotected intercourse or in cases of contraception failure (e.g., forgotten pills, condom breakage, or slippage). Taken as directed they reduce the risk of pregnancy by 75 percent. They provide no RTI or HIV protection.

3) Behavioral Methods:

There are a number of ways to prevent pregnancy that rely on human behavior rather than contraceptive technology.

a) Abstinence.

Abstaining from sexual inter-course, whether completely or periodically, is 100 percent effective, but may be difficult to maintain.

b) Fertility Awareness.

There are a variety of methods a woman can use to tell the fertile time of her menstrual cycle. These include calendar calculation, cervical secretions, basal body temperature (BBT), chemical ovulation prediction kits, and cervical changes. All of these methods are used in combination with either barrier methods (during the fertile time) or periodic abstinence (not having intercourse during the fertile time). Effectiveness is approximately 75 to 80 percent. Fertility awareness can also be used to time intercourse in order to facilitate pregnancy.

c) Lactational Amenorrhea Method (LAM).

This is a behavioral method used by women who have recently given birth. It involves simply the use of breastfeeding during the first six months postpartum, and requires that 85 percent of the baby's food be breast milk. During this period and under these conditions, LAM is 100 percent effective. It is also inexpensive, has no hormonal side effects, and benefits the baby.

WHY FEMALE CONTRACEPTION⁶?

Proportion use of male and female contraceptives:

Use of existing male and female contraceptives in developed regions:

Use of existing male and female contraceptives in developing regions:

"Data on contraceptive use were compiled primarily from surveys based on nationally representative samples of women of reproductive age (15 to 49 years old in general)

IMPLANT:

Implants are small pellets, composed of drug substance only, excluding excipients filled in flexible silicone tubes, capsules or rods which are inserted under the skin in the upper arm. They slowly release a hormone and are effective for up to 5 years and are 2-3mm in diameter. They are prepared in aseptic manner to be sterile. Here the partical size of drug is important and is usually kept large to produce a slow rate of absorption^7.

WHY IMPLANT AS CONTRACEPTIVE?

Effectiveness is an important and common concern when choosing a birth control method. The implant is over 99 per cent effective. Less than one woman in every 1,00 will get pregnant over three years ⁸. The implant is a long-acting reversible method of contraception. All long-acting methods are highly effective because while they are being used you do not have to remember to take or use contraception. It lasts up to three years.

Contraceptive implants have been approved in more than 60 countries and are currently being used by millions of women around the world ^9.

Comparison of various contraceptive methods ¹¹

TYPES OF IMPLANTS ⁹:

In 1983, Norplant became the first commercially available implant. Consisting of six hormone-releasing rods, Norplant has been recently replaced by simpler systems. The new products -- Implanon, Jadelle, and Sino-Implant (II) -- are just as effective as Norplant, but they are easier to insert and remove because they consist of only one or two rods. Sino-Implant (II) is being introduced at lower cost in parts of the developing world.

1)Implanon: 1 rod, provides contraception for 3 years, contains etonogestrel.

2)Jadelle: 2 rods, provides contraception for 5 years, contains levonorgestrel.

3)Sino-Implant (II): 2 rods, provides contraception for 4 years, contains levonorgestrel.

4)Norplant: 6 rods, provides contraception for 5-7 years (discontinued in 2008).

WORKING OF IMPLANT ¹²:

The main way it works is to stop your ovaries releasing an egg each month (ovulation). It also:

Thickens the mucus from your cervix. This makes it difficult for sperm to move through your cervix and reach an egg.

Makes the lining of your uterus (womb) thinner so it is less likely to accept a fertilised egg.

HOW EFFECTIVE IT IS¹²?

It is an extremely effective method of contraception (99.9%) The implant is inserted in on the first day of your period and it provides protection within 24 hours. Implants are a safe and effective method of long-term contraception for most women and they are reversible at any time. You will return to fertility immediately upon removal.

WHO CAN’T USE AN IMPLANT ¹²?

Most women can have an implant fitted. The doctor or nurse will need to ask you about your own and your family’s medical history to make sure that the implant is suitable. You should tell them about any illnesses or operations you have had.

An implant may not be suitable for you if:

1) You think you might already be pregnant.

2) You do not want your periods to change.

3) You take certain medicines.

4) Arterial disease or history of serious heart disease or strokes.

5) Thrombosis (blood clots) in any vein or artery.

6) Active disease of the liver.

7) Breast cancer or breast cancer within the last five years.

8) Migraines with aura.

9) Unexplained vaginal bleeding (for example, bleeding between periods or after sex).

WHEN CAN ONE START USING AN IMPLANT ¹²?

You can have an implant fitted at any time in your menstrual cycle if it is certain that you are not pregnant. If the implant is put in during the first five days of your period you will be immediately protected against pregnancy. If the implant is put in on any other day you will not be protected against pregnancy for the first seven days after it has been fitted. So you will need to use another method of contraception, such as condoms, during this time.

THINGS TO BE CONSIDERED BEFORE INSERTION OF IMPLANT ¹³:

1) Before having a implant you should make it sure that you are not pregnant already.

2) So to avoid such situation it is advisable to have it implant within the first five days of a woman’s menstrual period.

3) For the first two weeks after insertion use another method of birth control to avoid pregnancy.

4) When implant is done you will be provided with a card mentioning insertion and removal dates. So you have to take care of removal date when it is approaching.

INSERTION OF IMPLANT:¹⁴

The rods are inserted by a specially trained health care provider under the skin of the upper inside part of the non-dominant arm.

After injecting the insertion site with a local anesthetic, the health care provider makes a small incision in the arm and places the implants under the skin with a trocar, a sharp-tipped instrument that resembles a large ballpoint pen. There are no stitches.

A bandage is then placed over the wound and remains there for a few days to allow the site to heal.

The entire procedure takes about 10 minutes and is painless, except for any discomfort caused by the anesthetic injection.

For a few days afterward the recipient may also experience bruising, swelling, and discomfort at the insertion site.

The implants begin to work within eight to 24 hours of the procedure, but the woman should use additional contraceptive protection for a week or two, depending on the physicians recommendation.

MAINTAINANCE OF IMPLANT AFTER ITS INSERTION: ¹⁴

Implants do not require maintenance of any kind and do not affect the use of the arm once the insertion site has healed.

REMOVING THE IMPLANT. ¹⁴

When the time comes to remove the implants, the insertion site is again anesthetized and a small incision is made in the arm. Removal can be uncomfortable and is more difficult than the original procedure if scar tissue has formed over the implants. Removal usually takes 15 to 20 minutes, but may require more than one visit. The implants contraceptive action wears off a few hours after removal. Fertility is restored within a couple of weeks.

MEDICAL ASPECTS OF IMPLANTATION ¹⁵.

A) The environment of living tissues:

Many enzymes, which are capable of oxidation, reduction or hydrolysis, are present in the environment of living tissues.

Since many enzymatic reactions are characterized by various trace metals, through investigation is needed to search for

early or long-term effects of chemicals or additives, that could leach out or result from the degradation of implanted polymeric materials.

B) Reactions of host to implant:

Inflammation is the defensive reaction of the living body to any irritant, whether Physical (e.g., burns), chemical (e.g.,

toxins),or bacterial.Practicall any foreign agent can act as an irritant. The acute phase of the inflammatory reaction leads to the formation at the affected site, of an exudates and fibrinous network. Vascular and lymphatic systems are activated.

Leukocytes and mast cells accumulate and, with red blood cells, permeate the capillaries to the affected site.

C) Reaction of implant to host:

After a period of time, no polymer is totally impermeable to the body fluids. Fat soluble substances in blood such as cholesterol, testosterone, estradiol, and hydrocortisone, were absorbed by the lipophilic silicone elastomer. Environmental stress cracking can happen in some polymeric materials. Chemical breakdown will influence the mechanical strength of the implanted polymeric material.

Note: Therefore, an ideal implantable therapeutic system should be biostable, biocompatible with minimal tissue-implant interactions, non-toxic, noncarcinogenic, removable if required, and should release drug at constant, programmed rate for a predetermined duration of medication.

ADVANTAGES:^{16, 17}

1) Extremely effective close to 100 per cent.

2) Safe for most women.

3) The implant lasts for three years.

4) No need to remember to use.

5) Doesn't interrupt sex.

6) No estrogen related side effects.

7) Can stop the menstrual cycle.

8) Decreases menstrual cramps and pain.

9) Decreases anemia.

10) Possibly reduces the risk of pelvic inflammatory disease (PID).

11) Possibly reduces the risk of endometrial cancer.

12) It is effective for women who can’t tolerate synthetic oestrogens.

13) Ovulation returns within three weeks of removal.

14) Can be used while breastfeeding beginning 6 months after delivery (because no estrogen)

15) It may reduce heavy, painful periods.

16) At most, it starts working within 24 hours of insertion.

DISADVANTAGES:^{16, 17}

1) Offers no protection against sexually transmitted diseases (STDs)

2) Can be somewhat visible in thin women

3) Costs more than other types of birth control at the outset

4) Requires doctor's assistance and a surgical procedure for removal.

5) It may cause headaches, acne, nuisance, especially irregular bleeding, breast tenderness or increased appetite.

6) The implant can move from its original position under the skin.

7) There is a slight risk of infection or bleeding at the site of insertion.

8) Cannot be used by women with liver disease, breast cancer, unexplained uterine bleeding, blood clots.

9) Certain drugs anti-epilepsy drugs may reduce the effectiveness of implants.

FUTURE METHODS/PROSPECTS:⁴

Methods of contraception being developed include both variations of existing methods and new concepts. Among the modifications of current methods are biodegradable hormonal implants, subdermal hormonal pellets, injectable hormonal "microspheres" (hybrids of injectables and implants), and intravaginal hormonal rings. New methods include male hormonal contraceptive pills, hormonal patches for men and women, and vaccines against sperm, ovum, or hormones. Microbicides—chemicals that kill bacteria and viruses—are also being tested for use alone, or in combination with spermicides for dual protection.

CONCLUSION:

An implant is a novel and highly effective (99%) method for female contraception. As implants are long-acting (3-5years) there is no need to remember to use daily. Implants are safe to many women’s and reduce painful periods. Ovolution returns just few weeks (2-3) of implant removal. Decreases menstrual cramps and pain.

REFERENCES:

1. Ladipo O. A and Akinso S. A. Contraceptive Implants.JSTOR : African journal of reproductive of health

2. www.nhs.uk- Contraceptive implants and injection

3. www.thefreedictionary.com/contraception

4. Johnson, Kiersten B; Akwara, Priscilla; Rutstein, Shea O; Bernstein, Stan. Fertility preferences and the need for contraception among women living with HIV: the basis for a joint action agenda. AIDS: Official Journal of the International Aids Society. November 2009; Volume 23 - Issue - p S7-S17.

5. www.answer.com

6. www.malecontraceptive.org –why male new contraceptive?

7. N.K.Jain .Pharmaceutical Product Development .page no.64- 65.

8. www.plannedparenthood.org/terms-use-5488.htm

9. www.fhi.org/en/rh -Contraceptive Implants By Irina Yacobson, MD and Markus Steiner, PhD

10. www. arhp.org

11. www.merk.com Contraception review by Daniel R. Mishell, Jr., MD August 2007.

12. www.fpa.org.uk/information/readourinformationbooklets/implants

13. www.healthnlifestylemagzine.com

14. www.about.com/health

15. Joseph R.Robinson and Vincent H.L. Lee. Controlled drug delivery fundamentals and application. II^nd edition, page no.512-516.

16. www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf

17. www.healthsquare.com

Received on 25.11.2009 Modified on 22.01.2010

Research J. Pharm. and Tech. 3(2): April- June 2010; Page 339-343

Method	Percentage of Women Who Become Pregnant During the First Year of Use
	Perfect Use	Typical Use
Oral contraceptives	0.3 %	8 %
Implants	0.05 %	0.05 %
Skin patches and vaginal rings	0.3 %	8 %
Injections of medroxyprogesterone acetate	0.3 %	3 %
Condom	2 %	15 %
Diaphragm with spermicide	6 %	16 %
Cervical cap with spermicide	18 % (women who have had children)	40 % (women who have had children)
	9 % (women who have not had children)	18 % (women who have not had children)
Contraceptive sponge	26 % (women who have had children)	32 % (women who have had children)
	9 % (women who have not had children)	16 % (women who have not had children)
Intrauterine device (IUD)	0.1–0.8 %	0.1–0.8 %
Natural family planning (rhythm) methods	1-9 %	29 %
Withdrawal method	4 %	27 %