Occlusion of the fallopian tubes in some form is the underlying principle to achieve female sterilisation. This prevents contact between the sperm and ovum. The immediate complications relate to anaesthesia and to the surgical method used in sterilisation; they include pain at the incision site; fever; haematoma; and bladder or bowel injury [222, 225]. Remote complications include chronic pelvic pain; congestive dysmenorrhoea; menstrual abnormalities in the form of menorrhagia, hypomenorrhoea, or irregular periods [222]. Bilateral tubal ligation (BTL) is a highly effective method of contraception. When pregnancy does occur it is more likely to be ectopic [45, 225]. Regret is expressed by 7% of women; this is more common with younger women [45]. Tubal ligation has an inverse association with ovarian cancer and PID [23, 225].
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3.6.2 VASECTOMY
Surgical interruption of the vas deferens (vasectomy) is a permanent sterilisation operation done in the male [21, 222]. This blocks the passage of spermatozoa from the testis, and results, therefore, in the absence of sperm in the semen [45, 225]. Vasectomy is considered successful when semen analysis shows azoospermia in two consecutive specimens [21]. With vasectomy sterility is not immediate as it takes up to 3 months or 20 ejaculations for azoospermia to be achieved. This is due to sperm stored beyond the interrupted vas deferens [45]. Additional contraceptive protection is needed for about 2-3 months following vasectomy [222].
Complications may include: scrotal haematoma; wound sepsis, which may lead to scrotal cellulitis or abscess; and sperm granuloma, which is due to an inflammatory reaction to sperm leakage [222]. Vasectomy does not affect hormone levels, spermatogenesis, and rarely affects potency, or sexual performance [21]. Frigidity and impotence, when they occur are mostly psychological [222]. Vasectomy is a highly effective method, the operative technique is simple, and the operation can be done as an outpatient procedure [222]. Vasectomy has a failure rate of less than 1% [21, 45].
There is no medical condition that would absolutely restrict a person’s eligibility for sterilisation. Nevertheless, caution should be exercised when there are conditions that may promote intra- and post-operative complications. Male and female sterilisation should be regarded as permanent methods; the success of reversal cannot be guaranteed [17, 45]. Reversal of vasectomy with restoration of vas patency is possible in up to 90% of cases, as demonstrated by the presence of spermatozoa in the ejaculate, but the pregnancy rate is low (30-40%). This difference is attributed to the development of antisperm antibodies following vasectomy [21]. Surgical reversal of tubal ligation results in a pregnancy rate of 45% to 90%, and is associated with a higher risk of ectopic pregnancy. Female sterilisation has a higher failure rate and complication rate, and is more expensive than vasectomy [45].
3.7 BARRIER METHODS
Barrier methods act by preventing sperm deposition in the vagina or by preventing sperm from gaining access to the upper genital tract [222, 225]. The objective is achieved by mechanical devices or by chemical means that produce sperm immobilisation or by combined means [222]. These methods include spermicides, male and female condoms, diaphragms, and cervical caps [17, 23].
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3.7.1 SPERMICIDES
Spermicidal methods, available in the form of vaginal jellies, creams, gels, suppositories, vaginal sponge, and foams, in addition to their toxic effect on sperm (they produce sperm immobilisation), act as a mechanical barrier to the entry of sperm into the cervical canal. They may cause irritation to the vagina or vulva [23, 222].
3.7.2 CONDOMS
The male condom or contraceptive sheath is made of latex, polyurethane, or lamb ceca. It serves as a cover for the penis during coitus and prevents the deposition of semen in the vagina [23, 45]. The advantages of the condom are that it provides highly effective and inexpensive contraception as well as protection against sexually transmitted diseases (STDs). Condoms made of latex or polyurethane are impervious to most organisms that cause sexually transmitted diseases. Female condoms are pouches made of polyurethane, which line the vagina and also the external genitalia. The female condom gives protection against STDs and PID and has the additional advantage of being under the control of the woman. However, it is expensive and has a high failure rate [23, 222].
3.7.3 DIAPHRAGM
The diaphragm acts as a mechanical barrier between the vagina and the cervical canal. It is not a popular method as it requires fitting by a health professional, and the necessity for anticipating the need for contraception. There is also the risk of vaginal irritation and urinary tract infection (due to pressure of the rim against the urethra and alterations in the composition of the vaginal flora), and it has a high failure rate [23, 222].
3.7.4 CERVICAL CAP
Cervical caps are small cuplike diaphragms placed over the cervix that are held in place by suction. Tailoring the cap to fit each cervix is difficult, greatly limiting the usefulness of the method. With proper use the efficacy of the cervical cap is similar to that of the diaphragm [23].
Although barrier methods can be used without medical restrictions, due to their low level of effectiveness, they should be used with extra care by women in whom pregnancy is undesirable due to pre-existing medical conditions [17].
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3.8 NATURAL CONTRACEPTION
Natural contraception, also known as traditional or folk methods, includes fertility-awareness methods (rhythm or periodic abstinence); the lactation-amenorrhoea method; coitus interruptus; and post-coital douche.
Women are fertile for only a few days of the cycle. Fertility-awareness methods rely on the identification of the fertile period of a cycle and abstaining from sexual intercourse during that period. Accurate prediction or indication of ovulation is essential to the success of this method. The methods used to determine the approximate time of ovulation include:
recording the pattern of previous menstrual cycles (calendar method); noting changes in the basal body temperature (temperature method); and
noting changes in cervical mucus secretions as affected by menstrual cycle hormonal alterations (cervical mucus/Billings method).
These methods can be used either alone or in combination. In addition, symptoms that may occur just prior to ovulation, such as bloating and vulval swelling can be used as adjuncts in predicting the likely occurrence of ovulation. The disadvantages include:
difficulty in calculating the safe period;
compulsory abstinence from the sexual act during certain periods; and the need for both a regular menstrual cycle and a well-motivated couple.
In addition, conditions that cause a rise in body temperature, alter cervical mucus or vaginal discharge, or cause irregular vaginal bleeding may affect the use of this method [17, 23, 222].
Lactation provides a natural method of contraception. Suckling leads to increased release of prolactin, which results in a reduction in the release of GnRH, LH, and FSH. This causes anovulation and amenorrhoea [23, 222]. When using this method, the mother must provide breastfeeding as the only form of infant nutrition and must breastfeed through the night; amenorrhoea must be maintained and the method should be practiced as a sole form of birth control for a maximum of 6 months after birth [17, 23, 222].
Coitus interruptus necessitates withdrawal of the penis shortly before ejaculation, resulting in deposition of the semen outside the female genital tract. It has the disadvantage of demanding sufficient self-control by the man and it is possible for pre-ejaculatory fluid containing sperm to flow out before the penis is withdrawn [23, 222].
93 Plain water, vinegar, and a number of “feminine hygiene” products are used as post-coital douches. The douche flushes the semen out of the vagina, and the additives may possess some spermicidal properties. The method is ineffective and unreliable [23].
Natural family-planning methods have no known health risks or medical contraindications. Return to fertility is immediate. The methods have no cost and are readily available. Natural family planning, like any other client-dependent method, has a low level of effectiveness and, therefore, should be used with care in women with medical conditions that can be worsened by pregnancy [225].
3.9 CONTRACEPTIVE EFFICACY
Contraceptive effectiveness is one of the most important factors in choosing a method [227]. Contraceptive efficacy refers to how well a method would work in a clinical trial (perfect use), while effectiveness refers to how well it works in actual practice (typical use) [228]. Perfect use constitutes correct and consistent use of a method; the failure rate under perfect use is usually lower than under typical use [17, 228]. Contraceptive failure is measured using the pearl index or life-table [227]. The pearl index is the pregnancy rate per hundred woman years (HWY) of use, whereas life-index contraceptive efficacy is the number of women per hundred who become pregnant in the first year of use of a method [223, 228]. Use of the pearl index as a measure of contraceptive efficacy is limited by the fact that the effectiveness of a method improves with longer duration of use; this is because those who are prone to failure do so early [227, 228].
The effectiveness of a contraceptive is dependent on the inherent protection afforded by the method, and how correctly and consistently it is used [17, 228]. It is also affected by the age of the user (fertility declines with age) and frequency of intercourse [228]. User-dependent methods have higher failure rates [17, 227, 228]. The annual failure rate, under perfect use, of COCs is 0.3% and that of LNG-IUS is 0.1%. The failure rate of COCs increases with failure to maintain a regular schedule of use [228].
The most effective contraceptive methods are surgical sterilisation, long-acting progestogen- based contraceptives (DMPA, LNG-IUS, and implants), and IUDs, with first-year failure rates of less than 1% for perfect use. This is because these methods are not user-dependent [223, 227]. The least effective are barrier and natural-contraception methods. The failure rate of lactational amenorrhoea, under perfect use, is 0.4 to 2.0 per 100, and 3.2 per 100 for fertility-awareness methods. Cu-IUDs with ≥300mm2 surface area (gross life-table rate of 0.1
94 to 1.4 per 100) are more effective than Cu-IUDs with <300mm2 surface area (gross life-table rate of 0.6 to 1.5 per 100). The efficacy of short-acting hormonal contraceptives - injectables, oral contraceptives, transdermal patch, and vaginal ring - is comparable to that of Cu-IUDs with <300mm2 surface area [227]. Among emergency contraceptives, Cu-T-IUD causes 99% reduction in pregnancies, whereas progestin-only ECPs and COCs have a pregnancy- reduction rate of 89% and 75% respectively [228]. The probability of conceiving per month of exposure (fecundability) is about 20 to 25% in a normal fertile couple; more than 85% achieve conception within one year [23, 45]. The lifetime failure rate of all reversible contraceptives combined for women 15 to 45 years of age is 1.8; with sterilisation, it is 1.3 [228]. A summary of contraceptive efficacy, derived from the publications referenced in section 3.9, is presented in Table 3.1.
Table 3.1: Summary of contraceptive efficacy
Contraceptive method First year unintended pregnancy rates per 100
women (consistent and correct use)
Combined oral contraceptives 0.3
Progestogen-only pills 0.3
Progestogen-only injectable contraceptives 0.3
Implants 0.05
Copper-bearing IUDs 0.1-1.5
Levonorgestrel-releasing IUDs 0.1
Lactational amenorrhoea method 0.4-2.0
Fertility-awareness methods 3.2
Vasectomy 0.1
Tubal ligation 0.5
No method 85
3.10 CONCLUSION
Other than preventing pregnancy, contraceptives may exert effects that could be beneficial or harmful to the user. The benefits of contraceptive use outweigh the risks; it has been shown that more deaths occur from unintended pregnancies than from contraceptive use [45]. The annual global maternal mortality rate declined by 34% in the period 1990 to 2008 from 400 maternal deaths per 100,000 live births in 1990 to 260 maternal deaths per 100,000 live births in 2008. Avoidance of 1.7 million deaths in this period was attributed to fertility decline, which may partly be due to availability of contraceptives. The bulk of global maternal deaths occur in developing countries. It has been suggested that improved contraceptive availability in developing countries would prevent 94,000 maternal deaths annually [229].
95 When choosing a contraceptive method, many factors are taken into consideration. These include the efficacy of the contraceptive method, medical eligibility, unwanted effects, availability, acceptability, non-contraceptive benefits, and client’s preference. Most couples use contraception to space children or to limit family size, whereas others desire to avoid child bearing because they do not wish to have children, or because of pre-existing illnesses that are likely to worsen with pregnancy. Highly effective long-acting contraceptive methods should be recommended for women in whom unintended pregnancy would be detrimental to their health [17]. Some contraceptives can also be used for treatment of medical conditions and have also been known to accrue health benefits to the users [17]. Individuals should be informed of the available methods, their efficacy, unwanted effects, contraindications, and benefits [17, 45]. Knowledge of non-contraceptive benefits afforded by a method may improve its uptake [226].
An ideal contraceptive would be cheap, safe, highly effective, easy to use, and acceptable to the majority of the population [222]. No one single contraceptive meets this standard. There is ongoing research to identify better and safer contraceptives and to broaden the range of available methods.
The decision to use a contraceptive and the choice of method of contraception is, to a large extent, in the hands of an individual and their clinician, hence modifiable. This is further facilitated by the availability of a wide range of contraceptive methods. Effects on the health of users partly inform these decisions; therefore, availability of information is paramount. Although it is a rare disease, ovarian cancer is highly fatal. The effect of contraceptive use on the risk of ovarian cancer is discussed in Chapter 4.
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