Hormonal Pill(s) for contraception

There are two kinds of contraceptive pill:

  • Combined Oral Contraceptive (COC): Oestrogen and Progesteron
  • Progestogen only (POP/minipill)

Mode of action

  • Oestrogen
    • Inhibits ovulation by suppressing secretion of LH/FSH from the pituitary gland
      • Leads to failure of follicular maturation
  • Progestogen
    • Some degree of inhibition of ovulation (dose and preparation dependent)
    • Suppression or impairment of luteal function
    • Interferes with fallopian tube transport
    • Poorer secretory activity of the endometrium which resists implantation
    • Cervical mucus is more resistant to sperm penetration

Contents of the COC

  • Oestrogens: Ethinyl oestradiol and mestranol
  • Progestogens: Norethisterone, norethisterone acetate, ethynodiol diacetate, levonorgestrel, desogestrel, gestodene, norgestimate*, cyproterone acetate and drospirenone
    • * carry slightly increased risk of VTE

How to take the COC

Starting and taking the pill

  • First pill on first day of menstrual period
  • One pill taken each day for 21 days at approximately the same time each day
  • A seven day break follows during which a withdrawal bleed occurs
  • The cycle is repeated
  • Contraceptive protection is immediate if the pill is started on day one of a period.  If starting is delayed beyond the third day, extra precautions are required for the first seven days of the packet

Missed pill guidelines

If 1 pill is missed (at any time in the cycle)

  • take the last pill even if it means taking two pills in one day and then continue taking pills daily, one each day
  • no additional contraceptive protection needed

If 2 or more pills missed

  • take the last pill even if it means taking two pills in one day, leave any earlier missed pills and then continue taking pills daily, one each day
  • the women should use condoms or abstain from sex until she has taken pills for 7 days in a row. FSRH: ‘This advice may be overcautious in the second and third weeks, but the advice is a backup in the event that further pills are missed’
  • if pills are missed in week 1 (Days 1-7): emergency contraception should be considered if she had unprotected sex in the pill-free interval or in week 1
  • if pills are missed in week 2 (Days 8-14): after seven consecutive days of taking the COC there is no need for emergency contraception*
  • if pills are missed in week 3 (Days 15-21): she should finish the pills in her current pack and start a new pack the next day; thus omitting the pill free interval

Additional Points

Additional protection required if sickness/diarrhoea/antibiotics

NB First prescription– A monophasic COC containing 30μg of EE with a low dose of norethisterone of levonorgestrel is suitable (e.g. microgyon) and should be continued for at least 3 months then reasses side-effects/tolerability etc  (pay close attention to any change in BP/BMI.  Counsel about risk of MI.

Last prescription– COC pill can be taken from menarche to 50 if there are no risk factors.  If a smoker or risk of vascular disease, 35 is the cut off.

Pros and Cons of CHC

  • Pros
    • Effective; conveniant; fully reversible
    • Non-contraceptive benefits:
      • Lower risk of ovarian/endometrial cancer, lower risk of colorectal cancer, lower risk of ovarian cysts/benign breast disease, improves acne, reduces menstrual pain/blood loss/PMS
  • Cons
    • Side effects (headache, weight gain, mood changes)
      • break through bleeding
    • User dependent
    • Drug interactions (common- reduces the effectiveness)
    • Contraindications (vascular disease; migraine +/- aura; smokers >35; BMI >35
    • Systemic effects/risks (breast/cervical cancer; liver metabolism; arterial disease; VTE)

Progestogen only pill (POP/minipill) (desogestrel/cerazette)


  • COC contraindicated/intolerable side effects
  • Older women who smoke/obese (risk of DVT)- >35
  • Lactation
  • Mild hypertension
  • Alternative to COC before surgery
  • Sickle cell disease
  • Migraine


  • Pregnancy
  • Past or current CVD
  • After trophoblastic disease
  • Malignant breast disease
  • if irregular bleeding unacceptable
  • PMHx of ectopic pregnancy
  • Severe liver dysfunction
  • Drug interaction

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