Intrauterine Devices
Description
Although the intrauterine device (IUD) is a highly effective method of contraception, it is used by less than 2% of American women of reproductive age. The reason for such a small percentage stems from the withdrawal of FDA-approved IUDs in the 1970s. The Dalkon Shield IUD was withdrawn because of a series of litigations related to septic abortion deaths. The manufacturers withdrew their product because the cost of defending the lawsuits was deemed too expensive.Until as recently as 2000, the only 2 IUDs available in the United States were the Copper T380 (Pregna International; Mumbai, India) and the progesterone-releasing form, Progestasert (Alza; Mountain View, Calif). In December 2000, the FDA approved another form of IUD, the levonorgestrel intrauterine system termed Mirena (Berlex Laboratories; Montville, NJ). More than 2 million women in Europe have used this form of contraception in the past decade with great success.The T-shaped progesterone-releasing IUD Progestasert, which is placed into the uterine cavity, is made of ethylene vinyl acetate copolymer. It contains 38 mg of progesterone and minimal amounts of barium sulfate for greater visibility on x-ray films. The vertical limbs are 36 mm long, and the horizontal arms are 32 mm wide. It has a pair of dark-blue double-strings that hang from the lower limb. Approximately 65 mcg/d of progesterone is released from the progesterone form from a reservoir in its stem. This is a sufficient amount of hormone to last for 400 days; therefore, this IUD must be replaced yearly.
The Copper T380 was introduced in 1988. The T-shaped IUD is made of polyethylene with fine copper wire wrapped around the vertical stem. The string is clear or white and hangs from the lower limb of the IUD. This device consists of 308 mg of copper covering portions of its stem and arms. Contraceptive effectiveness continues for 10 years, after which time it must be replaced.
Mirena is similar in shape to the Copper T380 in that it also consists of a small T-shaped frame with a reservoir that contains levonorgestrel, a progesterone. This intrauterine system releases 20 mcg of levonorgestrel per day into the uterine cavity for as long as 5 years. It consists of a polyethylene frame with a cylinder containing a polydimethylsiloxane-levonorgestrel mixture enveloping the vertical arm. The cylinder is coated with a membrane that regulates the release of the hormone. This model is also visible on x-ray films.
An IUD causes cervical mucus to be thicker in consistency, thereby altering sperm migration. Uterotubal fluid and motility changes inhibit sperm migration. IUDs also result in endometrial suppression.
Efficacy
The failure rate is 2% with Progestasert (the progesterone form), 0.6% with the Copper T380, and of 0.1 % with Mirena. The percent of women who continue to use these forms of contraception is high after 1 year of use, 81% and 78% with Progestasert and Copper T380, respectively.
Advantages
IUDs produce no adverse systemic effects. Ectopic pregnancies are reduced overall; however, the ratio of extrauterine to intrauterine pregnancy is increased if conception does occur. Menstrual blood loss and dysmenorrhea are decreased with Progestasert. Twenty percent of women experience amenorrhea with Mirena.
Disadvantages
IUDs are associated with a risk of uterine perforation at the time of insertion. Increased dysmenorrhea occurs with the Copper T380. Increased menstrual blood loss occurs in the first few cycles with use of the Copper T380 and Mirena IUDs. Whether IUDs increase the risk of PID is controversial. IUDs have none of the potential noncontraceptive benefits of hormonal contraceptives. IUDs may be expelled unnoticed, and they do not protect against STDs.
Ectopic pregnancies are half as likely in IUD users as they are in women using no birth control. Ectopic pregnancies are more likely in women who use Progestasert than the Copper T380; however, the overall risk still remains less than for women who do not use birth control. Of those using Progestasert who become pregnant, approximately half of the pregnancies are ectopic. However, to reiterate, the risk of ectopic pregnancy is much less than it is in women who do not use any contraception.
Contraindications include a history of previous PID in the past year or active PID, an abnormal or distorted uterine cavity, undiagnosed genital bleeding, uterine or cervical malignancy, a history of ectopic pregnancy, increased susceptibility to infection (eg, those with leukemia, diabetes, valvular heart disease, or AIDS), Wilson disease, known or suspected pregnancy, a history of genital actinomyces, and active cervical or endometrial infections.
Sterilization
Description
Sterilization is considered an elective permanent method of contraception. Although both female and male sterilization procedures can be reversed surgically, the surgery is technically more difficult than the original procedure and may not be successful. In regard to reversal of sterilization, success is noted to be greater with tubal reanastomosis than with reanastomosis of the vas deferens.Female Sterilization
Approximately 1 million American women are sterilized either by surgery on the fallopian tubes or by hysterectomy each year. Female sterilization prevents fertilization by interrupting the fallopian tubes.Sterilization can be performed surgically in the postpartum period with a small transverse infraumbilical incision or during the interval period. Sterilization during the interval period can be performed with laparoscopy, laparotomy, or colpotomy. The methods of fallopian tube sterilization include occlusion with Falope rings, clips, or bands; segmental destruction with electrocoagulation; or suture ligation with partial salpingectomy.
The latest form of female permanent sterilization is the Essure system. This form of sterilization prevents fertilization by interrupting the fallopian tubes; however, the Essure system does not require surgical incisions and can be performed with the patient under local anesthesia. It is performed hysteroscopically, and a microinsert is placed directly into the fallopian tubes. During the first 3 months after the procedure, the fallopian tube and the microinsert create a tissue barrier that prevents sperm from reaching the egg. After the 3-month period, patients must undergo a hysterosalpingogram to ensure placement.
Efficacy
The United States Collaborative Review of Sterilization has examined the failure rate of female sterilization. Rates vary according to the procedure performed. The cumulative 10-year failure rate with each method of tubal ligation is as follows: spring clip method, 3.7%; bipolar coagulation, 2.5%; interval partial salpingectomy, 2%; silicone rubber bands, 2%; and postpartum salpingectomy, 0.8%.
The Essure procedure has undergone clinical testing in the United States, Europe, and Australia. Data from preliminary clinical testing demonstrate that the Essure system was 99.8% effective in preventing pregnancy after 2 years of follow-up. However, approximately 1 of 7 women in the Essure clinical studies did not achieve successful placement of both microinserts during the first placement procedure. Some of these women chose to undergo a second placement procedure, achieved successful placement of both microinserts during the second procedure, and subsequently were able to rely on Essure for contraception. Of women who relied on Essure, 98% rated their long-term satisfaction with Essure as "good" to "excellent."
Advantages
Female sterilization does not involve hormones. It is a permanent form of contraception. No data indicate that change in libido, menstrual cycle, or lactation occurs. Female sterilization is usually a same-day procedure.
Disadvantages
Female sterilization is a procedure that involves general or regional anesthesia. Patients who undergo the Essure system procedure require a backup method of contraception for the first 3 months. It is permanent contraception, and patients may regret the decision later, especially women younger than 30 years. Regret is difficult to measure because it encompasses a complex spectrum of feelings that can change over time. This helps explain that while some studies have reported "regret" in 26% of women, less than 20% seek reversal and less than 10% actually undergo the reversal procedure.
If the Essure microinserts must be removed for any reason, major surgery is necessary, requiring an abdominal incision and, most likely, general anesthesia.
No data are available on the safety or effectiveness of in vitro fertilization after the Essure procedure has been performed. Sterilization does not protect the patient from STDs. Sterilization causes short-term discomfort, and it involves all the risks of surgery.
Vasectomy
Vasectomy involves incision of the scrotal sac, transection of the vas deferens, and occlusion of both severed ends by suture ligation or fulguration. The procedure is usually performed with the patient under local anesthesia in an outpatient setting. Complications include hematoma formation and sperm granulomas. Spontaneous resolution is rare. After sterilization, remnant sperm remains in the ejaculatory ducts. The man is not considered sterile until he has produced sperm-free ejaculates as documented by semen analysis. This usually requires 15-20 ejaculations. Vasectomy prevents the passage of sperm into seminal fluid by blocking the vas deferens.Efficacy
The failure rate is approximately 0.1%.
Advantages
Vasectomy involves no hormones, is permanent, is an outpatient procedure, is quick, and carries minimal risk with regard to the procedure.
Disadvantages
Patients may regret their decision after the procedure. Alternative contraception is required until the ejaculate is deemed free of sperm. Vasectomy does not prevent STDs. Short-term discomfort occurs.
Emergency Postcoital Contraception
Description
Emergency postcoital contraception is defined as the use of a drug or device to prevent pregnancy after unprotected sexual intercourse. Unwanted pregnancy is common; worldwide, approximately 50 million pregnancies are terminated each year. In the United States each year, the widespread use of emergency contraception may have prevented more than 1 million abortions and 2 million pregnancies that end in childbirth.A variety of different methods of emergency contraception have been described. Emergency contraceptives available in the United States include the emergency contraceptive pills (ECP), the Copper T380 IUD, and the minipill emergency contraception method (MECM). Both the Preven kit and the Plan B kit are marketed as emergency contraceptives.Candidates for emergency contraception include reproductive-aged women who have had unprotected sexual intercourse within 72 hours of presentation independent of the menstrual cycle. No known absolute contraindications to any of these methods have been described because exposure to the high dose of hormones is short lived. However, cases of deep vein thrombosis have been documented in women using the ECP method.
Emergency Contraceptive Pills and the Minipill Emergency Contraception Method
The ECP mode is marketed as Preven. It consists of 2 pills, which each contain 0.5 mg of levonorgestrel and 100 mcg of ethinyl estradiol, ingested 12 hours apart for a total of 4 pills. The first dose should be taken within the first 72 hours after unprotected intercourse; however, studies demonstrate effectiveness if the pills are taken after that period.Only the progestin levonorgestrel has been studied for the use in MECM. It is marketed as Plan B. Its treatment schedule comprises 1 dose of 750 mcg levonorgestrel taken as soon as possible and no later than 48 hours after unprotected intercourse and a second dose taken 12 hours later.
The mechanism action of either the ECP or MECM is not clearly established. If administered before ovulation, both methods may inhibit follicular development and maturation, resulting in anovulation and deficient luteal function. Treatment following ovulation may affect the endometrium, thus inhibiting implantation. They also may affect tubal transport of the sperm or ova. However, menses and fertility return with the next cycle.
Efficacy
Most studies cite an effectiveness rate of 55-94%, with the true effectiveness rate likely to be approximately 75%. Based on one randomized trial comparing the ECP protocol with the MECM, the MECM seems to be just as effective with far less nausea and emesis. Patients must understand that the effective rate of 75% does not translate to a 25% failure rate. Instead, when considering 100 women who have had unprotected sexual intercourse during the middle 2 weeks of their cycle, approximately 8 will become pregnant. Of those 8 who have used ECPs, only 2 will then become pregnant. Despite this significant reduction in the rate of pregnancy, patients must understand that this method of contraception should be used only in emergencies and that they should be encouraged to use other more consistent forms of contraception.
Several factors complicate the calculation of a failure rate. Factors include dependence on the patient's history of their last menstrual period and day of exposure, effect of regular and irregular menstrual cycles on the calculation of the estimated time of ovulation, the possibility of the patient being pregnant, and the possibility that more than one unprotected coitus has occurred during that period.
Disadvantages
Adverse effects include nausea and emesis, minor changes in menses, breast tenderness, fatigue, headache, abdominal pain, and dizziness. Ectopic pregnancy is possible if treatment fails.
Copper T380 Intrauterine Device
The Copper T380 IUD can be inserted as many as 7 days after unprotected sexual intercourse to prevent pregnancy. Insertion of the IUD is significantly more effective than either the ECP or MECP regimen, reducing the risk of pregnancy following unprotected intercourse by more than 99%.For excellent patient education resources, visit eMedicine's: Men's Health Center and Pregnancy and Reproduction Center.
Also, see eMedicine's patient education articles Birth Control Overview,
Birth Control Barrier Methods,How to Use a Condom,
Vasectomy,
Tubal Sterilization,
Understanding Birth Control Medications (Contraceptives),
Birth Control Hormonal Methods, Birth Control Intrauterine Devices (IUDs)
Emergency Contraception.
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