Contraception
Definition/Introduction
Contraception is the act of preventing pregnancy. This can be a device, a medication, a procedure or a behavior. Contraception allows a woman control of her reproductive health and affords the woman the ability to be an active participant in her family planning. This review will not address abortion as that is not a way to prevent a pregnancy from occurring. Contraceptive methods are technological advances intended to overcome biology. The 20 century has seen the biggest advancements for female reproductive health expanding medical options, devices, and even procedures. This review will focus on medications, devices, and procedures available to couples to prevent pregnancy. It will not focus on behaviors and barrier methods available.
When considering contraceptive methods counseling should include efficiency, safety, acceptability and availability (including accessibility and affordability). Voluntarily informing the choice of contraceptive methods is an important guiding principle, and contraceptive counseling, when associable, is a marked contributor to the successful use of contraceptive methods.
Birth control methods are designed to prevent conception or interrupt or nullify implantation and growth. Conception can be prevented by hormonally disrupting the menstrual cycle (Oral contraceptive (OC) pills), by physically blocking the passageway (barrier methods or sterilization), or less successfully, by abstinence during fertile periods or withdrawal method. Implantation is impaired via the use of a foreign body (intrauterine device {IUD}) or surgical removal (Salpingectomy or Vasectomy)[1].
Contraception is best reviewed with the patient when efficacy is the top priority. The following are ordered by the most effective form of contraception to the least effective:
- Etonogestrel contraceptive Implant
- Levonorgestrel intrauterine system (LNG IUD)
- Copper intrauterine device (IUD)
- Female sterilization
- Vasectomy
- Injectables
- Combined oral contraceptives
- Progestin-only pill
- Patch
- Hormonal vaginal contraceptive ring
- Lactational Amenorrhea
- Diaphragm or cervical cap
- Sponge
- Male condom
- Female condom
- Spermicides
- Fertility awareness-based methods
- Withdrawal
- Emergency Contraception
- Copper IUD
- Emergency contraceptive pills
Medical devices used to prevent pregnancy include intrauterine devices or subdermal implants. The intrauterine device may or may not contain progesterone, and the subdermal implants all contain progesterone. These devices are commonly referred to as Long Acting Reversible Contraceptives or LARCs. The failure rate associated with the various forms of devices is less than 1 woman per 100 women per year making them the most effective form of contraception available, rates that are considered better than surgical sterilization. There are few absolute contraindications and relate to uterine anatomic defects or allergy to the medication. Contraceptive procedures involve surgical sterilization of the male and or female. The least invasive is a vasectomy, and then tubal occlusion methods follow. Hysteroscopic sterilization is no longer a practiced method at this time. Procedures are intended to be permanent although surgical reversals are possible. Failure rates are slightly higher than LARC methods but still, less than 1 woman per 100 women per year fails these surgical procedures.
The injectable currently on the market is a progesterone only, it does not have an estrogen component and many times results in irregular bleeding. Progesterone only forms alter cervical mucus and endometrial lining preventing conception. The injections are every 12 week and the failure rate is 6 women per 100 women per year.
The medications commonly thought of for contraception include combined hormonal pills, patches, rings, and progesterone only pills. Combined oral contraceptive pills are monophasic, biphasic and triphasic. They are dispensed monthly, quarterly or annual medications. The common combined oral contraceptive pill mimics the menstrual cycle, 21-24 days of estrogen and progesterone to suppress ovulation, alter cervical mucus and the endometrial lining preventing pregnancy and 5-7 days of placebo resulting in an observed menses. Continuous contraceptive pills use an 84-day continuous exposure of active phase pills and 7 days of placebo, or 365 days of active pills. These forms are equally efficacious and share failure rates regardless of the format. The combined hormonal patch and contraceptive ring offer a different entry point for the medication avoiding first pass effect and decreasing some side effects. The patch is changed weekly with a placebo week to mimic routine menses. The vaginal ring inserts for 3 weeks then removed for a placebo week to mimic menses. These formulations all provide the same failure rates of 9 per 100 women per year. A complete medical history and physical should be performed before starting any form of contraception as there may be relative and absolute contraindications. The CDC offers a medical eligibility criteria for contraceptive use based on the chosen form of contraception and patient medical conditions and is easily accessed by physicians and patients.