Introduction
The significant advantage of long-acting reversible contraceptive methods compared to other reversible contraceptive approaches is that users need not make any ongoing effort for its long-term and practical use. Moreover, after the removal of the long-acting reversible contraceptive device, the return of fertility is rapid. Currently, two types of long-acting reversible contraceptive devices are available in the United States. One is intrauterine devices (IUDs); the other is the etonogestrel single-rod contraceptive implant, also called a birth control implant. This article provides a comparison of these two devices in each aspect.
What Are Birth Control Implants?
Under the skin, the birth control implant is inserted. The birth control implant provides a sustained slow release of the progestin hormone. The various types of birth control implants are as follows;
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Levonorgestrel-Releasing Implants: They provide sustained release of Levonorgestrel which is very effective in contraception due to its strong antiestrogenic properties.
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Implanon: It is a single implant having an easy insertion and removal technique. It provides an average 450 pg/ml serum level of etonogestrel, which lowers steadily to approximately 200 pg/ml by the end of three years.
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Nestorone Implant: Nestorone is a progesterone derivative exerting a stronger progestational activity. A single implant releases Nestorone 150 µg/day, providing high contraceptive effectiveness for two years.
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Uniplant: It is a progestin implant that provides sustained release of nomegestrol acetate and has effective for one year. The single-rod implant is four cm in length and two mm in diameter. It is radio-opaque and can be easily visualized on X-ray.
What Is IUD?
IUDs are currently one of the most effective methods of contraception available. There are presently two types of IUDs used in the United States. One is the copper-containing IUD, and the other is the levonorgestrel-containing IUD. They both have failure rates of 0.08 % and 0.02 %, respectively, and similar success rates in preventing pregnancy. This makes them more than 99 % effective in providing contraception.
What Are the Differences Between Birth Control Implants and IUDs?
1. Mechanism of Action:
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Birth Control Implants: They work by slow and sustained release of hormones which results in anovulation (ovum does not get released from the ovaries), thinning of the endometrial lining (the inner tissue layer of the uterus that is necessary for conception), and thickening of the cervical mucus which creates a barrier making it impenetrable for sperm to reach up to the ovum.
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IUDs: The hormonal IUD slowly releases a progestogen hormone called levonorgestrel. This hormone thickens the cervical mucus so sperm cannot get through, and it also thins the lining of the uterus, which is necessary for the implantation of the fertilized egg. The copper IUD prevents fertilization primarily by inhibiting sperm migration and viability, as copper is toxic to sperm.
2. Initiation of the Contraception:
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Birth Control Implants: They work immediately if inserted within the first five days of menstruation. If they are placed after that timeline, another form of contraception is needed for at least seven days to avoid unintended pregnancy.
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IUDs: The copper IUDs provide contraceptive effects as soon as it is inserted, whereas hormone-releasing IUDs can provide effective contraception if inserted during the first seven days of menstruation.
3. Duration of Effectiveness:
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Birth Control Implants: The birth control implant provides more than 99 % of effectiveness in preventing pregnancy and can last up to three years, depending on the type of implant.
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IUDs: The levonorgestrel-containing IUDs are available in three different strengths Levonorgestrel, 13.5 mg, 19.5 mg, and 52 mg. At the same time, they all have a similar effectiveness rate at providing reliable contraception. The higher dose of levonorgestrel in the IUD, the longer its effectiveness. The 13.5 mg levonorgestrel IUD is approved for use for up to three years, and the 19.5 mg and 52 mg levonorgestrel IUDs are approved for up to five years. Whereas the copper IUD is approved for use for up to ten years for contraception.
4. Complications:
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Birth Control Implants: The medical complications associated with birth control implants include menstrual disturbances, weight gain, acne, dizziness, mood disturbances, headache, nausea, lower abdominal pain, loss of libido, hair loss, pain at the implant site, follicular cysts, and neuropathy.
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IUDs: The medical complications of IUDs include cervical dilatation, both insertion and removal of the IUDs pose a risk of vasovagal symptoms with bradycardia which may occur due to engaging with the cervix, displacement or accidental removal after insertion, rarely unintended pregnancy, risk of possible uterine perforation while inserting the IUDs.
5. Method of Insertion:
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Birth Control Implants: The doctor will first inject anesthetic medicine that numbs the spot to insert a birth control implant under the skin. After that, with a particular device, the doctor will insert the implant under the skin, usually on the arm. It is a quick procedure that only takes a few minutes. No stitches are needed. It is generally not visible under the skin, but one might feel it with a touch.
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IUDs: After examining the cervix, the doctor will cleanse the cervix and vaginal fornices using povidone-iodine. After that, the doctor may inject a paracervical block or apply the local anesthetic gel for anesthesia. After that, the doctor will use a sterile single-tooth tenaculum (specialized instrument) to grasp the anterior cervix lip and apply gentle traction to straighten the cervical canal and uterine cavity. This will help determine the uterine depth, typically between six cm to nine cm. IUD cannot be inserted if the uterine depth is less than six cm. After that, the doctor will insert IUD with its visible strings, which are cut into three to four cm with sharp scissors. The doctor will then ask the woman to come for a check-up after a week.
6. Effect on Breastfeeding:
Birth Control Implants: There are concerns regarding their adverse effects on breastfeeding due to hormonal changes.
IUDs: The copper IUD has the advantage in breastfeeding as it lacks hormonal content, which avoids any effect on breastfeeding. While hormone-releasing IUDs may pose the same issue while breastfeeding as birth control implants.
Conclusion
Both birth control implants and IUDs provide effective long-term and reversible contraception. However, some rare but severe complications, including ectopic pregnancy, uterine perforation, and pelvic inflammatory disease, limit IUD use in females, especially adolescents and young females. On the other hand, birth control implants work by releasing hormones in the blood circulation for their practical contraception function, which may create many unintended adverse effects due to hormonal changes in the natural hormonal cycle. Both devices come with their pros and cons. Women should consider all these parameters while selecting long-lasting reversible contraceptive methods.
