Contraception Update - Womens Health Clinic



Contraception Update

Dr Rachel Mackey

Womens Health Clinic

81 Upper Georges Street

Dun Laoghaire

womenshealthclinic.ie

01 2300556

Introduction

In these modern times women should be provided with a wide range of contraception choices. Many factors influence a woman’s choice of contraception method, including efficacy, safety, non contraceptive benefits, cost and personal considerations. As a result contraception is an area of women’s health in which new innovative products are introduced on a regular basis. This article deals with traditional methods, as well as some newer additions to the range of choices for both clinicians and patients.

Barrier contraception

Barrier contraceptive methods include the male condom, female condom and diaphragm. They are cheap, contain no hormones, provide significant protection against sexually transmitted infections (STI’s) and are used during sex only, removing the need for continuous compliance. However the failure rates are higher than other forms of contraception, primarily due to user error. Diaphragm use needs a degree of motivation, requires fitting and a small degree of training in order to use effectively.

Hormonal Contraception

Oestrogen/progestogen combinations

This has been traditionally the mainstay of hormonal contraceptive methods. As a group in general they provide easy convenient reliable contraception with few side effects or long term sequelae. They are suitable for most women with a few exceptions (smokers who are over 35 years of age, patients with a personal history of Venous ThromboEmbolism(VTE), migraine with aura, etc). Non-contraceptive benefits include control of menstrual flow, prevention of functional cysts, treatment of acne and improvement of Premenstrual Syndrome(PMS). The majority of preparations contain synthetic oestrogen in the form of ethinyl oestradiol (EE) and a progestogen, both in various dosages.The prescribing indication should determine your choice of preparation; the lowest oestrogen dose for contraception only, with increasing oestrogen content to achieve cycle control, etc. In general the lower the oestrogen content, the less likely it is the woman will experience oestrogen related side effects such as nausea, weight gain and breast tenderness.

Some new preparations have improved these benefits even further in recent years. Yaz® is a 24 day low dose monophasic preparation with 4 placebo tablets included, which reduces any oestrogen withdrawal symptoms traditionally associated with the 7 day break. PMS is also reduced with this 24 day regimen, as is menstrual flow. Qlaira® is a multiphasic preparation, the oestrogen component of which is oestradiol valerate. This has recently been licensed for use in the treatment of menorrhagia. Dianette® is an older monophasic preparation which although containing a high EE content, still has an important role to play in women whose needs include both contraception and control of acne. Other preparations which can also improve acne include those containing drosperinone - Yasmin® and Yasminelle®.

Nuvaring® is the vaginal contraceptive ring currently available in Ireland. This allows for further lowering of the EE dosage because the route of administration is transvaginal. It releases 15mcg of EE daily as compared to 20mcg which is the daily dosage of the lowest oral combined contraceptive preparations. It has comparable contraceptive efficacy to its oral counterparts. This is often useful in women who have tried several oral preparations but are unable to tolerate oestrogen related side effects.

Evra® is the transdermal contraception available in Ireland. This is a combined contraceptive which is dispensed through the skin via a weekly patch. It has comparable contraceptive efficacy to the oral version. Problems include local skin reactions, loss of adhesiveness and a higher steady state concentration of EE , which is a cause of concern as to an increased risk of VTE although preliminary studies have not shown an increased VTE rate in patch users.

Progestogen containing contraception

Injectable DepoMedroxyProgesterone Acetate (Depo Provera®)

This is a progestogen-only long acting reversible form of contraception. The intramuscular injection is administered every 12 weeks and is a highly effective form of contraception. Advantages include cessation of periods and it can be used in women in whom oestrogen use is contraindicated. There can be intermittent bleeding during the first year of use and a delay in return of fertility after stopping. Loss of bone mineral density has been associated with Depo Provera when used long term, however this has been disputed in some studies which have demonstrated a reversing of any bone loss after stopping.

Progestogen implants (Implanon®)

This is a single rod sub dermal implant which provides excellent contraception for approximately 3 years. It causes marked oligomenorrhoea and amenorrhoea but breakthrough bleeding can become an issue 12 to 18 months after insertion. Removal can prove difficult, particularly if the implant has been inserted too deeply. Nexplanon® is the updated system, which allows for more superficial insertion. Fertility is restored within weeks of removal.

Oral progestogens

Until recently the only oral progestogen contraceptive available was norethisterone 350mcg (Noriday®). This has been prescribed primarily for breastfeeding women and women in whom oestrogen containing contraception is contraindicated. The disadvantages were its compliance with usage, with just a 3 hour window daily during which the tablet can be taken. Failure rates as a result are higher than that of combined contraception.

The development of desogestrel 75mcg (Cerazette®) has allowed women for the first time to avail of a progestogen only form of contraception which has a contraceptive efficacy very similar to the combined oral contraceptive. It is a 28 day preparation which suppresses ovulation and can be taken within a 12 hour window daily. Bleeding patterns vary from amenorrhoea to a regular monthly bleed.

Intrauterine systems/Intrauterine devices

Intrauterine systems have grown in popularity as a form of contraception in recent years. Mirena®is the intrauterine device used in Ireland, which is a T-shaped device with a reservoir of levonorgestrel. It is suitable for use in both parous and nulliparous women, and lasts for five years. Insertion is relatively simple, and its contraception efficacy is excellent. The dosage of hormone released is the equivalent of two Noriday® tablets per week. It is licensed for both contraception and the management of menorrhagia. Amenorrhoea is achieved in 20% of Mirena® users. Occasionally progestogenic side effects are reported but this is uncommon.

Intrauterine devices are not commonly used by Irish women. The copper T380 coil is the most frequently used, which last for 10 years. The contraceptive failure rate is higher than that of the Mirena®, and there can be associated dysmenorrhoea and menorrhagia. However they do provide one of the few non hormonal forms of contraception, and therefore there is always a place for their usage.

Emergency contraception

There are two methods of emergency or postcoital contraception available in Ireland. Levonelle® is a single dose tablet of 1,500 mcg levonorgestrel which is administered up to 72 hours after unprotected intercourse. It has few side effects and its mode of action is uncertain. Its overall effectiveness is approximately 75%.

The Copper T380 coil can be used as emergency contraception, and is used up to 5 days after unprotected intercourse. It is then removed at the next period. Its effectiveness is 99%.

New developments

Currently on the market in the US is a 91 day preparation (Seasonique®). This contains 12 weeks or 84 tablets of EE 30mcg/levonorgestrel 150mcg combination, followed by 7 days of 10mcg EE. This is the bleeding interval, but the low dose EE addition prevent s any oestrogen withdrawal symptoms. Unplanned bleeding rates are comparable with 28 day preparations.

FDA approval has been given to a 365 day preparation (Lybrel®). This contains a low combined daily dosing of 20mcg EE/90mcg levonorgestrel.

Biodegradable contraceptive implants are being developed at present (Capnor®).This is a single rod of levonorgestrel which lasts for one year and which automatically biodegrades, thus avoiding the need for surgical removal.

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