- Overview
- Culture and Contraception
- Fertility Awareness-Based Methods
- Natural contraception
- Temperature Method
- Cervical mucus (Billing’s) Method
- Barrier Methods
- Intrauterine contraception (IUDs)
- Progestin implants
- Combined Oral Contraceptive Pills (COCPs)
- Progestin-only pills (POPs)
- Injectable progestins
- Patches
- Vaginal ring
- Emergency Contraception
Overview
Contraception refers to methods or devices used to prevent pregnancy. It is also known as birth control or family planning. Before prescribing a contraceptive, pregnancy should be excluded.
Gillick competency (Fraser Guidelines) should be used to prescribe contraceptives in underage patients.
About 50% of pregnancies are unplanned. Without contraception, 80 – 90% of women become pregnant within a year of having regular sexual intercourse.
No contraception is 100% effective at preventing pregnancy
Culture and Contraception
| Culture | Views on contraception |
|---|---|
| Hinduism | The use of contraception is encouraged. Hindu’s believe that they have a duty not to produce more children than their environment can support |
| Sikhism | The decision to use contraception is left to individual couples |
| Judaism | Orthodox Jews may prefer hormonal methods as they are perceived as more ‘natural’ than barrier methods. Calendar-based methods are discouraged as they typically coincide with ‘Niddah’ – the days when the woman is menstruating |
| Islam | The use of contraception is acceptable, although sterilisation may be discouraged. Throughout history, the ‘withdrawal method’ has been widely accepted in Islam |
| Protestants and Anglicans | Contraception is generally accepted |
| Roman catholic | Recommends the use of natural family planning to anticipate when the woman is least fertile, i.e. fertility-awareness-based contraception |
Fertility Awareness-Based Methods
Natural contraception
| Method | Examples |
|---|---|
| Rhytm | Temperature method, cervical mucus method, calendar method, symptothermal method |
| Coitus interruptus | |
| Lactational amenorrhoea |
Temperature Method
Following ovulation, a woman’s basal body temperature rises by 0.2 – 0.4 C because of progesterone secretion from the corpus luteum.
Cervical mucus (Billing’s) Method
At the time of ovulation, under estrogen influence, the mucus becomes excessive, clear and stretchy. This is called fertile mucus (peak mucus).
Four days following peak mucus day, the mucus becomes thick, sticky and opaque because estrogen level has dropped
Barrier Methods
Barrier methods prevent the sperm from reaching the egg and provide additional protection from sexually transmitted infections.
Male condoms are 98% effective when used correctly. Female condoms are 95% effective when used correctly
- Barrier methods
- Male condom
- Female condom
- Diaphragm
Intrauterine contraception (IUDs)
IUDs are long-acting reversible contraceptives that are often recommended over other forms of shorter acting contraceptions. They are small T-shaped pieces of plastic coated with either copper or progesterone-releasing compound. They are inserted into the uterus transvaginally.
IUDs can be inserted 4 weeks after birth, and immediately after abortion.
IUDs have been quoted to be >99% effective. If taken correctly during the course of 5 years, <1% of women will become pregnant.
| Intrauterine device | Description |
|---|---|
| Levonorgestrel-releasing intrauterine system (LNG-IUS, Mirena) | May be left up to 5 years. Lower risk of PID, dysmenorrhoea, blood loss and ectopic pregnancy than copper IUD |
| Copper T380 A IUD (Paragard) | May be left in for up to 10 years |
- Mechanism of action
- Biochemical and histological changes in the endometrium
- Impairs blastocysts’ implantation through enzymatic interference (copper IUD)
- Prevents proliferation of the endometrium, making implantation difficult (hormonal IUD)
- Thickens cervical mucus, creating a plug that the sperm cannot penetrate (hormonal IUD)
- Benefits of IUD
- Highly effective
- Good for “poorly compliant” patients
- Lasts several years
- Periods eventually stop or lighten
- Contraindications for IUD
- Pregnant
- Vaginal bleeding of unknown aetiology
- Acute infection of the reproductive tract
- Prior ectopic pregnancy
- History of an STI in the past 3 months
- Anatomic anomaly or fibroid uterus
- Menorrhagia (ParaGard)
- Current breast cancer (Mirena)
- Copper allergy, Wilson’s disease (ParaGard)
- Disadvantages of IUD
- Insertion and removal require a trained provider
- Perforation and Pelvic inflammatory disease can occur
- Method failure can lead to an ectopic pregnancy
- Can cause cramping and increased/prolonged bleeding
- Expulsion and displacement of the IUD can occur with uterine contractions
- Longer and heavier periods during the first few months
Progestin implants
Progestin implants are rod-shaped implants that slowly release progesterone and provide contraception for up to 3 – 5 years. They are commonly placed subcutaneously in the biceps groove and are covered in a polymer to prevent fibrosis.
Progestin implants can be fitted on or before day 21 of the menstrual cycle and provide immediate protection. If fitted after day 21, additional contraception will need to be used for 7 days. They can be fitted immediately after a miscarriage
Progestin implants are 99.5% effective at preventing pregnancy. 1 in 200 women will get pregnant in the course of a year when used as the sole form of contraception.
| Implant | Description |
|---|---|
| Levonorgestrel subdermal implant (Jadelle) | 2-rod progestin implant. Approved for 5 years |
| Etonorgestrel subdermal implant (Implanon, Nexplanon) | Single-rod progestin implant. Approved for 5 years |
- Mechanism of action
- Thickens cervical mucous
- Prevents the proliferation of the endometrium, making implantation difficult
- Inhibits ovulation
- Contraindications to progestin implant
- Pregnancy
- Current or past history of thrombosis or thromboembolic disorders
- Liver tumour (benign or malignant)
- Active liver disease
- History of breast cancer or current breast cancer
- Benefits of progestin implant
- Highly effective
- Good for “poorly compliant” patients
- Lasts for up to three years
- Less risk of expulsion (compared to intrauterine devices)
- Does not affect bone density (unlike injectable progesterone)
- More likely to inhibit ovulation compared to POPs, hence reduced risk of ovarian cysts and ectopic pregnancy
- Disadvantages of the progestin implant
- Unexpected bleeding pattern (20% have amenorrhoea, 60% have irregular periods, 20% have frequent or prolonged bleeding). Mostly improves within 3 months
- Spontaneous “Silent” expulsion
- More cumbersome to implant/replace
- Side effects of progestin implants
- Acne
- Breat tenderness
- Mood swings
- Changes in libido
- Small risk of infection at the implant site
- Drug interactions
- CP450 inducers: recommended to use additional contraception for the duration of treatment and 4 weeks after
Combined Oral Contraceptive Pills (COCPs)
Combined oral contraceptives are frequently prescribed, even though they are the most complex method of contraception. They contain Estrogen and Progestin components, which are taken in cycles. Both monophasic and diphasic pills are in a 21-day supply with a 7-day break to allow breakthrough bleeding.
COCPs are started on day 1 of the cycle. If starting after day 4, another method of contraception should be used for 7 days. If changing from POPs, start on the first day of the cycle or exclude pregnancy (if amenorrhoea), then start on any day. It can be started 3 weeks after delivery and immediately after abortion.
COCPs are > 99% effective when taken correctly.
| COCPs | Description |
|---|---|
| Monophasic pills | Fixed dosage pills |
| Multiphasic pills | Variable dosage pills. Exposes the patient to fewer hormones, thereby reducing adverse effects |
- Mechanism of action
- Prevents ovulation by impairing dominant follicular development
- Thickens cervical mucus (progesterone component)
- Endometrial hypoplasia (progesterone component)
- Contraindications of COCPs
- Pregnancy or nursing (reduces milk letdown and increases risk of VTEs)
- History of Thromboembolism/pulmonary embolism
- History of Coronary Artery Disease
- History of CVA
- Smoker > 35 years of age
- History of breast or endometrial cancer
- Unexplained vaginal bleeding
- Abnormal liver function
- Severe cholesterol or triglyceride elevations
- Migraines
- Seizure disorder (can interfere with seizure medications)
- High risk for vascular disease and over the age of 40 **
- Hypertension
- Diabetes
- Complications of COCs
- Deep venous thrombosis
- Pulmonary embolism
- Cerebrovascular accident
- Myocardial infarction
- Hypertension
- Cholelithiasis
- Cholecystitis
- Hepatic adenoma
- Benefits of COCPs
- Highly effective when taken appropriately (> 99% effective)
- Reduces the risk of endometrial and ovarian cancer
- Reduces risk of osteoporosis
- Treats a variety of disorders
- Disadvantages of COCs
- Must take the pill daily
- Preparations may be confusing
- Long list of contraindications
- Long list of drug interactions
- Increased risk of cervical dysplasia and cancer
- Increased risk of gallbladder disease
- Increased risk of benign hepatic tumours (especially adenoma)
- Side effects of COCs
- Nausea
- Headache
- Breakthrough bleeding
- Weight gain
Progestin-only pills (POPs)
Progestin-only pills are normally taken when COCs are contraindicated. They contain small doses of progesterone taken daily without estrogen, i.e., they are taken every day of the cycle with no placebo phase. Missing a pill results in fertility for about 48 hours.
POPs can be started on the first day of the cycle with immediate protection. If started after 5 days, the barrier method can be used for 2 days.
POPs can be started immediately after abortion and pregnancy.
- Mechanism of action
- Thickens cervical mucus
- Alters the endometrium, making it difficult for implantation to occur
- High doses of POPs can inhibit ovulation
- Contraindications of POPs
- Previous cysts or ectopic (have a slightly increased risk of ectopic pregnancy)
- Side effects of POPs
- Irregular ovulatory cycles
- Breakthrough bleeding
- Increased formation of follicular cysts
- Acne
- Breast tenderness
- Risk of ectopic pregnancy
- Benefits of POPs
- May be taken by women when oestrogen-containing contraceptives are contraindicated
- Can be used when breastfeeding
- Disadvantages of POPs
- Less effective (failure rate of 8%)
- Must take at the same time every day
- Irregular menses
Injectable progestins
Injectable progestins are typically given every 3 months. The most problematic side effect is bone demineralisation. They can also cause an erratic return to normal menstruation after being stopped.
Injectable progestins can be administered within 5 days of the start of the cycle. If it started on any other day, another method of contraception should be used for the first 7 days. It is usually started 6 weeks after pregnancy and immediately after abortion.
Injectable progestins are 99% effective at preventing pregnancy.
| Injectable progestin | Description |
|---|---|
| Depot-Medroxyprogesterone Acetate (DMPA, Depo-Provera) | The most common preparation of injectable progestin. Administered every 90 days (3 months) via intramuscular route. Adverse effects and contraindications are similar to progestin-only pills |
| Norethisterone enantate (Noristerat) | Administered every 60 days (2 months) via the intramuscular route. Less effective than DMPA. A short-term option for women waiting for sterilisation |
- Mechanism of action
- Prevents endometrial proliferation
- Thickens cervical mucus
- Prevents ovulation
- What is the most problematic side effect of injectable progestins?
- Bone demineralisation
- The maximum effect is at 1 year, then increases gradually with more years of use.
- Women should be advised to take Vitamin D and do weight-bearing exercises
- Benefits of injectable progestins
- Highly effective (>99%)
- Injections are only needed every 3 months
- Reduces the risk of endometrial and ovarian cancers
- Useful in the treatment of menorrhagia, dysmenorrhea, and endometriosis
- May be used in patients where oestrogen-containing contraceptives are contraindicated
- Can be used in breastfeeding patients and epileptics
- Disadvantages of injectable progestins
- Bone demineralisation: hence should not be first-line in women < 18 or > 45 years old. Avoid in patients with risk factors for osteoporosis
- Increased risk of cervical carcinoma in situ
- Delay in return of regular ovulation when discontinued (median of 10 months)
- Side effects of injectable progestins
- Irregular menses
- Depression/mood disorders
- Weight gain (2 – 3 kg per year)
- May worsen premenstrual syndrome and premenstrual dysphoric disorder
- Contraindications of injectable progestins
- Undiagnosed abnormal bleeding
- Severe cardiac disease
- Acute liver disease
Patches
Patches are analogous to COCs and have a similar adverse effect and contraindication profile. Their usage has declined over the years due to litigation, but there is no evidence supporting increased morbidity with patch vs. other combined hormonal contraceptive methods.
| Patch | Description |
|---|---|
| Norelgestromin/Ethinyl estradiol transdermal (Ortho Evra Patch): | Applied for three weeks, then removed |
Vaginal ring
Etonorgestrel/ethinylestradiol (NuvaRing)
Emergency Contraception
Emergency contraception is a post-coital method of contraception. They prevent ovulation, fertilisation and/or implantation from occurring. These methods do not cause any alteration to an embryo after implantation.
| Emergency contraceptive | Description | Pregnancy rate if taken within 120 hours |
|---|---|---|
| Levonorgestrel (LNG) | Progesterone-only emergency contraception (POEC). This is the traditional ‘morning after pill’. It should be taken within 72 hours of coitus | 2.2% |
| Ulipristal acetate (UPA) | Selective progesterone receptor modulator (SPRM). It is more effective than levonorgestrel and can be taken up to 120 hours (5 days) after coitus. | 1.4% |
| Copper IUD | This is the most effective method of emergency contraception, even for women presenting after 72 hours | <1% |