Combined Oral Contraceptives

Introduction

Most COCs contain the oestrogen ethinyl estradiol (EE) and a progestin (e.g. norethisterone, levonorgestrel, drospirenone). There are different formulations of COCs.

  • Monophasic COCs have the same dose of oestrogen and progestin throughout the pill pack.
  • Biphasic, triphasic and quadriphasic pill packs mimic the oestrogen and progesterone levels during a menstrual cycle.

NOTE:

  • COCs containing levonorgestrel and norethisterone have been used for many years and are associated with a lower risk of VTE than other COCs.
  • Drospirenone is structurally related to spironolactone; it has progestogenic, antiandrogenic, and anti-mineralocorticoid activity.
    • There is no evidence that a certain type of progestin in a COC formulation is any more effective in treating hyperandrogenic symptoms, such as acne or hirsutism, than another type.
    • In patients with conditions requiring chronic therapy with medications that may increase potassium, monitor serum potassium during the first treatment cycle and periodically thereafter if patient begins medication or develops a condition that increases risk for hyperkalaemia.



Indications

COCs is used for

NOTE: The contraceptive use should be considered along with WHO Medical Eligibility Criteria for Contraceptive Use.



Precautions

Breastfeeding

  • Oestrogens may decrease milk supply.
  • WHO medical eligibility criteria for contraceptive use advises delaying use of oestrogen-containing methods until 6 months postpartum for those who are primarily breastfeeding because of the importance of breastfeeding on infant health in low-resource settings.

Postpartum

  • Delay use until at least 3-6 weeks postpartum due to VTE risk

Smoking

Surgery

  • Where prolonged immobilisation is expected

Uncontrolled hypertension



Contraindications

  • Breast cancer (current or recent)
  • Known ischemic heart disease
  • Migraine with aura - due to an increased risk of stroke
  • History of stroke
  • History of venous thromboembolism (VTE)
  • Severe (decompensated) cirrhosis



Regimen

Most COCs are available as 28-day regimens, where active tablets are taken for 21, 24 or 26 days followed by inactive use. A hormone-free interval <7 days is thought to reduce the incidence of hormone withdrawal symptoms and, in some cases, it may increase contraceptive effectiveness by further suppressing ovarian.

NOTE:

  • Low-dose oestrogen COCs (e.g. ethinyl estradiol 20 mcg) appear to be as effective as standard dose (e.g. ethinyl estradiol 30-35 mcg), with a slightly higher incidence of breakthrough bleeding, especially at first.
  • COCs containing 50 mcg of ethinyl estradiol should generally not be used for contraception but are available for acute treatment of uterine bleeding.



When to Start for Contraception

A woman can start using COCs any time she wants if it is reasonably certain she is not pregnant.

  • For immediate contraception, start with an active pill within the first 5 days of your period starting.
  • If you start active pills after this, use additional contraceptive methods until you have taken active pills for 7 days.



What to Expect

While taking inactive pills, a withdrawal bleed (similar to a period) should start. However, sometimes this may not occur. Continue taking the pills as normal but consider the possibility of pregnancy if the pill has not been taken correctly or if 2 withdrawal bleeds in a row are missed.

Irregular bleeding or spotting is common at first but this usually settles down after 2-3 months.



When is It Less Effective

Effectiveness may be reduced by



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