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Introduction

Emergency contraception is an important post-coital method of contraception to prevent pregnancy from occurring.
  • The risk of pregnancy is highest during the 6 days prior to ovulation, and on the day of ovulation
  • Ovulation can be variable and unpredictable but is typically around day 14 of the cycle
Emergency contraception methods do not cause abortion. Instead, they prevent ovulation, fertilisation, and/or implantation. There are three methods by which this can occur:
  • Oral progesterone-only emergency contraception (POEC) – levonorgestrel (LNG)
    • The traditional ‘morning after pill’. More effective the sooner it is taken. Should be taken within 72 hours of intercourse.
    • Pregnancy rate if taken within 120 hours – 2.2%
  • Selective progesterone receptor modulator (SPRM) – ulipristal acetate (UPA)
    • A newer drug – widely used in Australia – use may be more limited in UK
    • More effective than levonorgestrel and can be used up to 120 hours (5 days) after unprotected sex
    • Pregnancy rate if taken within 120 hours – 1.4%
  • Copper intra-uterine contraceptive device (Copper IUD)
    • Intra-uterine device is the most effective method (99% effective), and should be offered to all women, even those presenting after 72 hours
    • The IUS (intrauterine system) aka progesterone containing intrauterine system (e.g. mirenais NOT indicated
    • Pregnancy rate if taken within 120 hours – <1%
In the UK, the emergency contraceptive pill (levonorgestrel) is provided free of charge at most health care centres (e.g. GUM clinics, GP’s). You can also buy it at most pharmacies, if you are over 16 (~£25) without a prescription.
  • In Australia both LNG and UPA are available without prescription over the counter in pharmacies
It is important to counsel women about the available options – remembering to including the copper coil – as it is under-utilised and the most effective method – and is especially recommended at the high risk time around ovulation, when the pill methods are much less effective.
None of the methods should be used when a known pregnancy is present (i.e. implantation has already occurred).

Assessment and History

  • Document date of LMP (last menstrual period)
  • Ask about:
    • Timing of unprotected sexual intercourse
      • If >72 hours – IUD or ulipristal recommended, <72 hours any of the three options
    • Current contraceptive methods
      • If on the pill, ask about missed pills
      • May be appropriate to talk about proper use of barrier methods and assess if they are being used correctly
    • Possibility of non-consensual sex and offer support and referral if appropriate
  • Remember: there is no time in the menstrual cycle where there is no risk of pregnancy. The risk is lowest in the first 3 days. 
  • Important to advise the patient that:
    • Methods are not 100% effective
    • Their next period may be early or late
    • They should have a pregnancy test if their next period is >7 days late
    • They should see a doctor immediately if they develop lower abdominal pain
    • They should consider ongoing long-term contraceptive options
    • Discuss the risk of STI – and consider sexual health screening
  • As well as emergency contraception – don’t forget to offer ongoing long-term contraception

Emergency oral preparations

More effective the sooner they are taken.
Both pill methods work by preventing ovulation by preventing the LH surge which typically occurs just before ovulation. HOWEVER – this means that if ovulation has occurred – they are not effective. This is important to remember when prescribing. Ovulation typically occurs around day 14 of the cycle – if the women presents at this time – consider copper coil.

Levonorgestrel

The same progestrogen found in the IUS (Mirena). It is a progestrogen only pill. Thus it is safe in breastfeeding, and for women in whom oestrogens are contraindicated.

Dose – 1.5mg

  • Consider 3mg dose if raised BMI (>26) or on liver-enzyme inducing medications
    • Phenytoin and carbamazepine are likely the most commonly seen examples
    • Raised BMI reduces the efficacy of LNG
  • In emergency situations when only 30mcg levonorgestrel pills are available (e.g. the progesterone-only contraceptive pill such as Microlut) – this may be taken as an alternative – but 25 tablets (!) will need to be taken TWICE – 12 hours apart – for a total of 50 tablets.

Contraindications

  • Severe liver disease
  • Known allergy to levonorgestrel

Side effects

  • Menstrual irregularities
  • For most women the next period will be normal, but it can be 2-7 days late.
  • There may be irregular bleeding during the next menstrual cycle
  • Nausea
  • Vomiting
  • Breast tenderness

Efficacy

  • Most effective within 12 hours after sexual intercourse
  • 95% if <24h
  • 85% if 24-48h
  • 58% if 49-72h
  • May be given up to 120h, but is not recommended. Between 72-120h, an IUD or ulipristal is recommended as they are more effective

Vomiting

  • If vomiting occurs within 2 hours of administration, another pill should be given. If vomiting continues, consider IUD, or consider another dose, with an antiemetic (domperidone recommended).
  • Another form of contraception – e.g. COCP or POP can be started immediately

Prescribing

Can be taken as many times as necessary, even within the same menstrual cycle however, not recommended, as it is not as reliable as regular contraception.

A barrier method of contraception needs to be used for 7 days (COCP), or 3 days for POCP.

  • If due to missed oral contraceptive pill advise to take the next one within 12 hours of taking levonorgestrel – but re-iterate she will need to use barrier contraceptive for the time periods outlined above

If there is any lower abdominal pain before the next period, she should consult immediately to rule out ectopic pregnancy
If she has any concerns (e.g. if next period is late, could be pregnant) to seek medical advice.

Ulipristal Acetate

Dose

  • 30mg as soon as possible after intercourse. Should not be used >120 hours after intercourse
  • Should not be used more than once in one menstrual cycle
  • The only oral method licensed for use between 72 and 120 hours

Contraindications

  • Contraindicated in uncontrolled asthma
  • Avoid breast-feeding for 36 hours (precautionary, no evidence)
    • LNG and copper coil are both safe with breast-feeding
  • Severe liver disease

Efficacy

  • More effective than LNG, but less effective than copper coil
    • Efficacy also reduced by increased BMI, but not to the same extent as LNG and the dose does NOT alter

Side effects

  • Reduces efficacy of COC and POP
    • As such, when (re-)starting long term progestogen containing contraceptives – patients need to wait 5 days before starting – AND then use a barrier method until the long-term contraceptive method becomes effective
  • Side effects – GI disturbance, dizziness, fatigue, headaches, menstrual irregularities
  • Advise repeat dose of vomiting within 3 hours of taking (note this timeframe is different for LNG)

IUD (copper coil) as emergency contraception

  • More effective than levonorgestrel – around 99% effective
  • Maintains its efficacy right up until 5 days after sexual intercourse
  • Copper has multiple effect on the fertilisation and implantation process
    • Inhibits sperm penetration of cervical mucus
    • Toxic effects on the ovum
    • Inflammatory reaction effects on the endometrium prevent implantation
  • Effective up to 5 days after intercourse
    • Ensure that the patient has only had unprotected sex once since the last period – if not, the IUD is only effective if fitted within 5 days of the earliest date of ovulation.
  • Also provides ongoing contraception for up to 10 years
  • Is not affected by diarrhoea or malabsorption
  • Efficacy – 99% effective
  • Risk factors and side effects – same as the IUD in normal circumstances
    • Remember; risk of infection within 20 days of fitting, and increased risk of PID. Recommended to perform sexual health screening at time of insertion
  • Fitting – same as IUD in normal circumstances, except:
    • Swabs for STI recommended to be taken in all instances
    • Antibiotic prophylaxis may be given at the time of insertion if deemed to be high risk for PID: age <=25, new sexual partner, >1 sexual partner in last 12 months
  • Next period – should be at the normal time
  • Follow up –same as IUD in normal circumstances. Check up at 3-6 weeks. IUD can then be removed if the patient does not wish to use it as a form of long term contraception
  • NB – Mirena (progesterone containing IUD) is NOT indicated for emergency contraception

Ethics

Those who believe life begins at fertilisation may argue that abortion can occur with these methods, and may have moral objections. However, the methods do not cause any alteration to an embryo after implantation.

  • In the UK, a 2002 Judicial Review concluded that – legally – life begins at implantation and not at fertilisation.

References

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