Combined Oral Contraceptive Pill

How They Work; Pros and Cons

Composition

Estrogen and a progestin. Most OCPs are low dose and contain 20-35ug of Ethinyl Estradiol. The progestins found in the majority of OCPs are Norethinedrone, Levonorgestrel, Desogestrel or Norgestimate.

Mechanism of Action

Inhibition of ovulation and interference with ovum transport, endometrial development and cervical mucus production.

Dosage

There are various regimes available. One tablet is taken daily for 21 days with 7 days off, or daily for 28 days with 7 days of placebo pills in the last week. The OCP should be started within the first seven days of the menstruation cycle.

Alternatively, extended cycle regimes are also available. An extended cycle regimen called Seasonale is now available in Canada which provides women with a 91 day cycle, resulting in four periods per year. This is achieved with 84 active days of therapy followed by seven days of placebo.

Twenty-one (21) or Twenty-eight (28) day regimen products can also be taken continuously for more than 3 weeks by eliminating the placebo week and/or week off. This is a safe option and is usually recommended for 3 months at a time.

Advantages

1. Highly effective and reversible 
2. Improved cycle control and less dysmenorrhoea 
3. Improvements in acne 
4. May lower the risk of pelvic infection and tubal infertility 
5. Decreased menorrhagia, improved sleep and overall quality of life in perimenopausal women 
6. Lower risk of ovarian cancer and endometrial cancer 
7. Fewer benign ovarian cysts 
8. Less benign breast disease 
9. Protection from osteoporosis

Disadvantages/Side Effects

1. Intermenstrual bleeding 
2. Breast tenderness 
3. Nausea 
4. Amenorrhea 
5. Weight gain/bloating 
6. Headaches 
7. Mood changes 

Rarely

1. Venous thrombo-embolism 
2. Liver Adenoma 
3. Ischemic stroke/Myocardial infarction 

Efficacy

The OCP has an efficacy (theoretical effectiveness) of 99.9 percent, with a typical user failure rate of three percent per year. The Pearl Index is 0.1-0.2 (failure rate per 100 women using the method for one year)

Contraindications/Poor candidates

Absolute

1. Active thrombophlebitis or venous thromboembolic disorder 
2. Acute or chronic obstructive liver disease with elevated liver enzyme levels or compromised liver function 
3. Known or suspected breast cancer 
4. Undiagnosed genital bleeding 
5. Women over 35 who smoke cigarettes 
6. Known or suspected pregnancy 
7. Arterial Thrombosis/Ischemic heart disease 
8. Migraines with focal neurologic signs

Relative

1. Hypertension 
2. Diabetes complicated by vascular disease 
3. Sickle cell anemia 
4. Systemic Lupus Erythromatosis 
5. Inflammatory bowel disease 
6. Hyperlipidemia 
7. Migraines-non-focal 
8. Concomitant. Use of certain medications (Rifamicin, Dilantin) 

Follow-up

Early on to dispel concerns. Three months has been the traditional time for the first visit however an earlier follow-up appointment may improve adherence especially in first time users.

Missed Pills

If one pill is missed, the user should be instructed to take the combined OCP as soon as she remembers, even if it means taking two pills in one day.

If a woman misses two pills in a row during the first two weeks of the pack, she should take two pills on the day that she remembers as well as two on the following day. She also requires a back-up method of contraception (condoms) for seven days after missing pills.

If two pills are missed in a row in the third week of the pack, the user should throw out the remainder of the pack and start a new pack immediately. She may not have a period that month. She also requires a back-up method of contraception (condoms) for seven days after missing two pills.

If three pills are missed in a row, she should throw out the remainder of the pack and start a new pack immediately. She also requires a back-up method of contraception (condoms) for seven days after missing three pills. She may not have a period that month.