Lecture 8 Contraception - PDF

11/25/2023 Gynecology Dr. Shahla Raoof M.B.Ch.B., F.K.B.M.S. (Obst & Gyne) , MRCOG (P1) 1 Contraception...

11/25/2023 Gynecology Dr. Shahla Raoof M.B.Ch.B., F.K.B.M.S. (Obst & Gyne) , MRCOG (P1) 1 Contraception 1  11/25/2023 Methods of contraception Hormonal contraception: Combined hormonal contraception :pills,patch,ring Progestogen-only contraception:progestogen-only pill,Implant,progestogen-only injectable,progestogen-releasing intrauterine system (mirena) Copper intrauterine device Barrier contraception: condoms(for male and female),diaphragm,cap Sterilization: female sterilization(laparoscopic or hysteroscopic), male sterilization(vasectomy) Fertility awareness-based methods (natural family planning) Lactational amenorrhoea Correct and consistent use of effective methods of contraception can prevent most unintended(unplanned)pregnancies. None of the existing methods of contraception are 100% effective at preventing pregnancy. The effectiveness of a method depends on both mechanism of action and correct and consistent use. 2  11/25/2023 Many women who present with an unintended pregnancy have used a method, but it is usually a method of low effectiveness(e.g. condom)or a method that has been used incorrectly or inconsistently(e.g. missed oral contraceptive pills). The most effective methods of contraception are the long acting reversible methods of contraception (LARC) or so called (fit and forget methods) such as the copper intrauterine device(Cu-IUD),levonorgestrel intrauterine system(LNG- IUS) and progestogen-only implant. Mechanism of action: The current available methods of contraception work in the following ways: Prevent ovulation: this is the mechanism of action of the following methods: combined hormonal methods (pill, patch and vaginal ring), progestogen-only injectables, progestogen-only implant (Nexplanon®), oral emergency contraception, lactational amenorrhoea. Prevent sperm reaching the oocyte: female sterilization and male sterilization (vasectomy). Prevent an embryo implanting in the uterus: this is a mechanism of action of the Cu-IUD and LNG- IUS. Allow sperm into the vagina but poison them: mechanism of action of spermicides. Allow sperm into the vagina but block further passage: mechanism of action of diaphragm and cap. 3  11/25/2023 Efficacy and effectiveness The efficacy of a method depends on its mechanism of action. However, real-life effectiveness depends on compliance and continuation with the method. Compliance is influenced by the route of administration; some methods are easier to use than others. Continuation with a method depends on the acceptability to the user. Failure rates during perfect use show how effective methods can be, where perfect use is defined as following the directions for use. Failure rates during typical use show how effective the different methods are during actual use (including inconsistent or incorrect use). Percentage of women experiencing an unintended pregnancy within the first year of use with typical use and perfect use 4  11/25/2023 Safety Most women who use contraception are fit and healthy. However, some health conditions may be associated with real or theoretical risks if a particular contraceptive method affects the health condition. The World Health Organization (WHO) developed a system addressing medical eligibility criteria for contraceptive use. The WHO Medical eligibility criteria for contraceptive use (MEC) is a guidance document that contains recommendations for whether or not women with given medical conditions are eligible to use a particular contraceptive method, based upon on evidence and also expert consensus opinion. The MEC categories are 1–4. Medical eligibility criteria (modified from WHO) 5  11/25/2023 Examples of WHO medical eligibility criteria category 4 conditions and use of combined hormonal contraception Interaction with other medicines There are a number of medicines (some anticonvulsants, antifungals, antiretrovirals and antibiotics) that induce liver enzymes cytochrome P450, and will reduce the efficacy of hormonal contraception such as CHC pills, patch or ring, progestogen-only implant and progestogen-only pill (POP). If a woman using enzyme-inducing medication wishes to use one of these hormonal methods, then the consistent use of condoms is also advised. Alternatively, she could consider use of the progestogen-only injectable, Cu- IUD or LNG-IUS, since efficacy of these methods is not affected by drugs that are enzyme inducers. Effectiveness of the combined oral contraceptive pill (COCP) (and all other methods) is not affected by administration of most broad-spectrum antibiotics. 6  11/25/2023 Drugs known to decrease efficacy of hormonal contraception through induction of liver enzymes (oral contraceptive pills, patch, ring and implant) Non-contraceptive health benefits of hormonal contraception Barrier methods, particularly condoms, protect against sexually transmitted infections. 7  11/25/2023 Emergency contraception 1. Copper-intrauterine device 2. Ulipristal acetate(UPA) 3. Levonorgestrel(LNG) Combined hormonal contraception Combined hormonal contraception CHC methods contain two hormones: an oestrogen and a progestogen. They are available as oral pills, a transdermal patch and as a vaginal ring. They are similar in terms of effectiveness, safety and side-effects. These methods all work by inhibition of ovulation. 8  11/25/2023 Combined oral contraceptive pill Most of the commonly used COCPs are ‘low dose’ and contain ethinyl oestradiol in a dose of 15–35 µg. The progestogens that are used in currently available pills are often referred to as second-generation (levonorgestrel, norethisterone), third-generation (gestodene desogestrel) and fourth-generation progestogens (drospirenone and dienogest). The combined hormonal transdermal patch The combined hormonal transdermal patch releases 33.9 µg ethinyloestradiol/day and norelgestromin 203 µg/day. It is applied to the skin of the lower abdomen, buttock or arm for 7 days, although it can be applied to any skin covered area, except the breast. The regimen usually involves application of patches for a total of 21 days followed by a 7-day hormone-free interval. Continued use (tricycling or tailored use) is also possible. Some women may experience problems with patch adherence or skin sensitivity to the patch. 9  11/25/2023 The combined hormonal ring The combined hormonal ring is a flexible ring of 54 mm diameter that releases 15 µg ethinyloestradiol and 120 µg etonorgestrel daily, and as such is the lowest dose combined hormonal method. The ring is self inserted and worn in the vagina for 21 days, followed by a 7-day hormone-free interval, during which a withdrawal bleeding occurs. Women should not feel discomfort from the ring and it can be removed for a short time (less than 3 hours) and can be cleaned and replaced. 10  11/25/2023 The oral contraceptive pill. A: Combined hormonal patch. B: combined hormonal vaginal contraceptive ring. Route of administration of contraceptive and duration 11  11/25/2023 Progestogen-only contraceptive methods Progestogen-only methods are available as oral, injectable, implant and intrauterine system. The mechanism of action of the method and the bleeding pattern appear to depend on the dose of progestogen and also the route of administration. The injectable, implant and desogestrel-containing POP inhibit ovulation. Lower-dose POP formulations inhibit ovulation only inconsistently. All progestogen-only contraceptive methods, regardless of the route of administration, thicken cervical mucus so reducing sperm penetrability and transport. The levonorgestrel intrauterine system (LNG-IUS) has little effect on ovarian activity but causes marked endometrial atrophy, which prevents implantation if ovulation and fertilization occur. 12  11/25/2023 Progestogen-only pill Unlike the COCP, the POP needs to be taken continuously. Medium- dose pills (e.g. containing desogestrel) inhibit ovulation in 99% of cycles, but lower-dose pills inhibit ovulation in less than one half of cycles, relying on the cervical mucus effect for contraception. Side- effects of all POPs include possible irregular bleeding, persistent ovarian follicles (simple cysts) and acne. Implant A single rod (Nexplanon®) containing the progestogen etonorgestrel providing contraception for 3 yearsNexplanon® is a flexible rod, similar in size to a match stick (40 mm × 2 mm) and is inserted subdermally 8 cm above the medical epicondyle, usually of the non-dominant arm. Insertion is conducted under local anaesthesia using a specially designed insertion device. Nevertheless, poor insertion technique can still result in deep insertion with consequent difficult removal, so insertion should only be conducted by clinicians who have undertaken appropriate training. The implant is not usually visible, but should be easily palpable. Nexplanon® contains a small quantity of barium, which permits it to be visualized by X-ray. It can also be localized using low-frequency ultrasound probes, which can help aid removal of implants that are not easily palpable 13  11/25/2023 Progestogen-only injectable The most commonly used injectable worldwide is a depot injection of medroxyprogesterone acetate, which can be administered intramuscularly (buttock, upper arm, lower abdomen) as the formulation Depoprovera® (150 mg) or subcutaneously as the micronized lower-dose formulation of Sayana press® (104 mg). Both intramuscular and subcutaneous preparations have similar features: same mode of action (inhibition of ovulation), same efficacy, similar injection interval (every 12–14 weeks) and similar bleeding pattern (over 50% amenorrhoea rates at 1 year). The injectable is the only hormonal method that may delay return of fertility after discontinuation. In some cases it may take up to 1 year after the last injection for ovulation to return. There is no permanent impairment of fertility but this delay makes the injectable an inappropriate method for women wishing short-term contraception. 14  11/25/2023 Progestogen-releasing intrauterine system The 52 mg LNG-IUS (Mirena®) is licensed for 5 years for contraceptive use (but if inserted in women 45 years or older, may be used for contraception until the menopause) The LNG-IUS works by exerting a potent hormonal effect on the endometrium, which prevents endometrial proliferation and implantation. Its progestogenic effect on thickening the cervical mucus also impedes entry of sperm. The LNG-IUS does not prevent ovulation. In the first few months of use, many women experience unpredictable bleeding. Women should be advised that this usually improves with time and many women will eventually have lighter or absent periods. Provision of quality information about side-effects in advance of fitting a LNG-IUS is important to reduce unnecessary discontinuation rates. Reported side effects of the LNG-IUS include acne, breast tenderness, mood disturbance and headaches. Progestogen-releasing intrauterine system The most notable non-contraceptive benefit of the 52 mg LNG-IUS is that of reducing HMB (reduced by 90% at 12 months). It is more effective than oral treatments, such as norethisterone, the COCP and tranexamic acid, at reducing menstrual blood (see Chapter 4, Disorders of menstrual bleeding). It is also effective for treating dysmenorrhoea, pain associated with endometriosis and adenomyosis and protecting the endometrium against hyperplasia. 15  11/25/2023 Intrauterine contraception Intrauterine methods of contraception include the copper intrauterine device Cu-IUD and the LNG-IUS. The Cu-IUD duration of use is between 3 and 10 years, depending on the device used and age of woman at insertion. If a woman has a Cu-IUD inserted at 40 years or above, it can be left in situ until the menopause. For women who have a 52 mg LNG-IUS inserted at 45 years or over, the device can be left for contraceptive purposes until the menopause. With both Cu-IUD and LNG-IUS, threads protrude through the cervical canal into the upper vagina to permit easy removal. Once inserted, the effectiveness of IUDs does not rely on the user and so typical failure rates are much lower than the shorter-acting methods of contraception. In addition to routine contraception the Cu-IUD can also be used for emergency contraception. Evidence suggests that the Cu-IUD and the LNG-IUS do not cause a delay in return to fertility or increase the risk of infertility and women should be advised of this. Mode of action: IUDs stimulate an inflammatory reaction in the uterus. The concentration of macrophages and leucocytes, prostaglandins and various enzymes in both uterine and tubal fluid increase significantly. It is thought that these effects are toxic to both sperm and egg and interfere with sperm transport. If a healthy fertilized egg reaches the uterine cavity, implantation is inhibited. 16  11/25/2023 Bleeding pattern with IUD: Although women with the LNG-IUS tend to experience lighter, less painful menses, women using the CuIUD may experience more painful or heavier menses. The use of a non-steroidal anti-inflammatory drug at menses may help lessen the pain and blood loss. Tranexamic acid during menses may also reduce blood loss with a CU-IUD. Alternatively a woman could switch to a LNG-IUS. Women using an IUD should be informed that their overall risk of ectopic pregnancy is much reduced compared with women who are using no contraception. However, if a pregnancy does occur with an IUD in situ then the ‘relative’ risk of that pregnancy being ectopic is higher. If women become pregnant with an IUD in situ, an ultrasound scan should be conducted to exclude ectopic pregnancy. It is generally advisable that IUDs should be removed before 12 weeks’ gestation in view of the greater risk of miscarriage, preterm delivery, septic abortion and chorioamnionitis if the device is left in situ. Insertion of IUD An IUD can be fitted at any point in the cycle provided there is no risk of pregnancy. Insertion is associated with the following risks: 1. Perforation 2. Expulsion 3. Infection 4. Missed thread 17  11/25/2023 Barrier contraception Condoms Male condoms are cheap and widely available. They protect against STIs including HIV. They are the only reversible male method. Typical failure rates are in the region of 24% since they rely on the user to put it on it correctly, before penetration and before every act of sex. The female condom is a lubricated polyurethane condom that is inserted into the vagina. It also protects against STIs. Diaphragm and cap These are latex or non-latex devices that are inserted into the vagina to prevent passage of sperm to the cervix. They can be inserted in advance of sex. Caps fit over the cervix whereas diaphragms form a hammock between the post-fornix and the symphysis pubis. Caps and diaphragms are often used in conjunction with a spermicide. Disadvantages are that women need to be taught how to insert and remove the device and typical failure rates in the region of 18% are reported. In some women their use may be associated with increased vaginal discharge and urinary tract infections. 18  11/25/2023 Spermicides Spermicide alone is not recommended for prevention of pregnancy as it is of low effectiveness. Nonoxynol 9 (N-9) is a spermicidal product sold as a gel, cream, foam, sponge or pessary for use with diaphragms or caps. Some data have suggested that frequent use of N-9 might increase the risk of HIV transmission. It is therefore no longer recommended for women who are at high risk of HIV infection. 19  11/25/2023 Female sterilization This is a permanent method of contraception that prevents sperm reaching the oocyte in the Fallopian tube. It can be performed by (1) laparoscopy, (2) hysteroscopy or (3) laparotomy (e.g. at caesarean section). 20  11/25/2023 Vasectomy This is the technique of interrupting the vas deferens to provide permanent occlusion. The so-called ‘no scalpel’ vasectomy involves a puncture wound in the skin of the scrotum under local anaesthesia to access and then divide and occlude the vas using cautery. There is a small risk of a scrotal haematoma and infection with the procedure. Postvasectomy semen analysis should be conducted at 12 weeks to confirm the absence of spermatozoa in the ejaculate. Alternative contraception should be used until azoospermia is confirmed. The failure rate is significantly less than female sterilization at approximately 1 in 2,000. 21  11/25/2023 Thank You 43 22