The Health Blog

What is a contraceptive patch?

A contraceptive patch is a transdermal patch applied to the skin that releases synthetic estrogen and progestin hormones to prevent pregnancy. They are thought to have the same effectiveness as the combined oral contraceptive pill. Currently the only publicly available contraceptive patch is marketed under the brand name Ortho Evra. Contraceptive patches are often referred to by the slang term “the patch”.

How does it work?

Contraceptive patches are synthetic hormone contraceptives, similar in action to the combined oral contraceptive pill. The contraceptive patch product Ortho Evra contains 0.75 mg ethinylestradiol and 6.0 mg norelgestromin hormones in a single patch. The gradual release of hormones over the course of each week (approximately 20 µg/day ethinylestradiol and 150 µg/day norelgestromin) act much like contraceptive pills do. Most commonly ovulation is inhibited entirely, preventing pregnancy. Less often the cervical mucus is thickened, making it more difficult for sperm to cross through the cervix and for fertilization to occur. When both of these mechanisms fail (meaning that ovulation occurs and sperms successfully pass through increased mucus), fertilization may result. As with other hormonal contraceptives, a third mechanism by which the patch may prevent the implantation of a zygote onto the endometrium lining of the uterus is by thinning the endometrium lining.

How effective is it?

When used according to instructions it’s more than 99 per cent effective. Research shows it’s less effective in women weighing 90kg (14 st) and over.

The patch lasts for seven days and is used for three weeks out of every four.

• When applied on the first day of your period it provides immediate protection from pregnancy.
• The next two patches are applied on day 8 and day 15 of the cycle.
• After three weeks you have a patch-free week and during this time you get a bleed. A new patch is applied after seven patch-free days and the process starts again.

The patch is very sticky and should stay on during bathing, swimming, saunas or exercise. If it does come off, reapply it as soon as possible.

* If it’s been off for less than 24 hours, just reapply or use a new one.
* If it’s been off for longer than 24 hours, use an additional method of contraception for the next seven days.

How do you apply it?

A woman applies her first patch onto her upper outer arm, buttocks, abdomen or thigh on either the first day of her menstrual cycle (day 1) or on the first Sunday following that day, whichever she prefers. The day of application is known from that point as patch change day. Seven days later, when patch change day comes again, the woman removes the patch and applies another to one of the approved locations on the body. This process is repeated again on the next patch change day. On the following patch change day, the patch is removed and not replaced. The woman waits 7 days without a patch in place, and on the next patch change day she applies a new patch.

The patch can be worn anywhere except the breasts or any area that’s sore or irritated.

Advantages:

• You only have to remember to replace the patch once a week.
• It’s highly effective when used correctly.
• It doesn’t interfere with sex and is easy to use.
• As the hormones go straight into the bloodstream, the effectiveness of the patch isn’t affected by vomiting or diarrhoea.

Disadvantages:

• It’s visible.
• It may cause skin irritation in a small number of women.
• Like the Pill, temporary side effects when you first start may include headaches, nausea, breast tenderness, mood changes, bleeding between periods and weight gain or loss.
• More serious side effects would be similar to those seen with the Pill.

Who can use it?

The patch won’t suit everyone. Reasons not to use it include:

• you think you might be pregnant
• you smoke and are 35 or older

You also shouldn’t use it if you have now, or have had in the past:

• blood clots in any vein or artery
• circulatory disease or heart abnormality
• diabetes or severe migraine
• breast cancer
• active liver or gall bladder disease

References: Wikipedia.org and BBC.co.uk