Female subdermal contraceptive

In the current market there are several types of contraceptives, among which the hormonal contraceptives stand out. In September, the contraceptive Implanon NXT® was released, which together with Dretine® and Dretinelle®, are contraceptives currently financed by the National Health System. It is a hormonal contraceptive that is highly effective.

Hormonal methods

Contraceptive methods include two large groups, the non-hormonal ones (among which the reversible ones stand out, such as the condom and the copper intrauterine device, and the non-reversible ones like the tubal ligation) and the hormonal ones.

The latter are based on the administration of hormones, and currently on the market we find:

The combined

They combine two different types of hormones, estrogens (female sex hormones that are produced in the ovaries) and gestagens (hormones derived from progesterone that cause changes in the innermost layer of the womb). Among the combined ones, with an oral route of administration, but there is also the transvaginal route in the form of a vaginal ring and the transdermal route, which consists of a patch that is applied to the skin and that must be distinguished from the subdermal route.

The simple ones

Those that contain only gestagens. Hormonal methods that contain only gestagens also have several presentations: the oral route, the intrauterine route with the IUD that releases gestagens, or the subdermal route, that is, a rod that is placed under the skin and that is the case with Implanon NXT® or Jadelle®.

How is the new contraceptive put on and how does it work?

For the placement of the rod, the doctor will perform, in the same consultation, a very small incision under local anesthesia in the arm. You will place the rod and then, without the need to apply stitches, you will leave a small bandage for 24 hours. It is usually placed between the first and fifth day of the menstrual cycle, counting from the first day of menstruation.

His duration is three years and for its extraction the same incision is used as for placement. If you want to withdraw it before three years, it can be done.

The rod produces a constant release of a gestagen which is a hormone derived from progesterone. Continuous-release gestagen is contraceptive by several mechanisms of action:

• Suppresses ovulation through an inhibition of hormones produced in the pituitary gland (hormone-producing gland located at the base of the skull).
• Reduces the mobility of the fallopian tubes, making it difficult for the sperm to pass to the ovum and of the possible fertilized ovum to the uterus.
• Produces changes in the endometrium (internal mucous layer of the uterus that forms the virtual cavity) that make it difficult for a fertilized egg to implant.
• Thickens cervical mucus making it difficult for sperm deposited in the vagina to pass on their way to the ovum.

These combined mechanisms of action achieve a high contraceptive efficacy of this method. Contraceptive failures are measured by the, which estimates the percentage of women who become pregnant after using the contraceptive method for one year. The Pearl Index for subdermal implants is 0.00-0.07.

Advantages

Like all medications, this new contraceptive method has certain advantages, among which are:

• It is effective for three years but can be withdrawn at any time if desired and restored immediately.
• It does not require a daily, weekly or monthly reminder of other hormonal contraceptives.
• It can be used in lactation.
• It can be used in women over 40 years of age or with other risk factors for combined estrogen and progesterone contraceptives such as women over 35 years with migraines without aura, in obese women and in hypertensive women.
• Improves menstrual cramps.
• Its contraceptive efficacy does not vary at times with gastrointestinal problems such as gastroenteritis or diarrhea.

Drawbacks

• The poor control it produces is the great disadvantage of this method. Very different and irregular bleeding patterns can occur from one woman to another, with both the disappearance of menstrual bleeding and intermittent bleeding being frequent, as well as, more rarely, prolonged bleeding. Good information from the doctor is very important so that the user can make an appropriate decision.
• It depends on a doctor to remove the implant at the time the woman decides to interrupt treatment, as well as require trained personnel to insert it.
• Taking some drugs can decrease the contraceptive efficacy of the implant. This is the case of epileptics.
• It does not protect against (like the rest of non-barrier contraceptives) so if there is suspicion of being exposed to them, a condom should be used.