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)

Indications

• 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

Contraindications

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