From the 1960s, when high-dose combined oral contraceptives were used as emergency contraception in preventing pregnancy in rape victims, we have evolved a licensed, safe and effective set of options.
However, despite emergency contraception being freely available, in 2008 there were more than 195,296 terminations of pregnancy performed in England and Wales, more than 91 per cent of which were NHS funded.
With every termination costing on average £672, the NHS bill in 2008 was more than £129 million, making further improvements in emergency contraception efficacy an imperative medically, socially and financially.
Until 2009, in the UK there were only two emergency contraception options - levonorgestrel (LNG) or an IUD. LNG is taken as a single oral 1.5mg dose as soon after unprotected sexual intercourse (UPSI) as possible and is licensed for use for up to 72 hours.
Although believed to work by altering tubal motility, disrupting ovulation or fertilisation, or via inhibition of implantation,1 this has not been proven. Efficacy falls rapidly following UPSI - offering 95 per cent efficacy during the first 24 hours, 85 per cent after 25 to 48 hours and 58 per cent efficacy after 49 to 72 hours.2
In one study comparing the old 'Yuzpe' method (using the combined oral contraceptive pill, two tablets, each with 50 micrograms ethinylestradiol and 250 micrograms levonorgestrel, taken as soon after UPSI as possible, and then repeated 12 hours later) and LNG, the crude pregnancy rate was 1.1 per cent with LNG compared with 3.2 per cent with the Yuzpe regimen.3 The study also showed increasing pregnancy rates against time after UPSI, where LNG is associated with a 0.5 per cent pregnancy rate if taken within 12 hours of UPSI increasing to 4.1 per cent if delayed until 61 to 72 hours.
There was a linear increasing pregnancy rate of 50 per cent for every consecutive 12-hour delay, demonstrating an ongoing, if diminishing, protective effect even after 72 hours, which some clinicians justify as a 'better than nothing' reason to use LNG outside its licence (limited to 72 hours) when the patient presents late but will not accept an IUD.
An alternative hormonal method
Since October 2009, there has been an alternative hormonal method - ulipristal acetate (UPA). This first-in-class progesterone receptor modulator is licensed for emergency contraception up to 120 hours (five days) following UPSI.
This should be given as a single oral dose (30mg). Although not specifically clear, its primary mechanism of action is thought to be inhibition or delay of ovulation. A single mid-follicular dose has been shown to suppress growth of lead follicles, but endometrial changes may also play a role; early luteal administration of UPA results in delayed endometrial maturation and alterations in progesterone-dependent markers of implantation.
Comparing the two hormonal methods: both are available free of charge, although LNG is also available free under patient group direction at pharmacies and clinics to women under 24 (or can be bought OTC). LNG, the current UK standard of care, only offers efficacy over 72 hours, while UPA offers sustained efficacy for 120 hours.
|EMERGENCY CONTRACEPTION OPTIONS|
There are currently three licensed options for emergency contraception in the UK.
Comparing the efficacy of both methods: the results from two independent RCTs showed the efficacy of UPA to be non-inferior to that of LNG in women requesting emergency contraception up to 72 hours after UPSI or contraceptive failure.4 When data from the two trials were combined via meta-analysis, the risk of pregnancy with UPA was significantly reduced compared with LNG (p=0.046).4
In an open-label clinical trial of more than 1,000 women treated with UPA 48 to 120 hours after UPSI, a 2.1 per cent pregnancy rate was seen.5 In addition, the second comparative trial described above also provided data on 100 women treated with UPA 72 to 120 hours after UPSI, in whom no pregnancies were observed.
The alternative to hormonal methods is an IUD implanted post-UPSI. Also free of charge to the patient, its use is complicated by the need for specialist insertion. The advantage of an IUD is that it is effective up to five days after either UPSI or ovulation. Unfortunately, despite a high efficacy (quoted as 99 per cent, although recent studies suggest it may be higher)6 and significant cost-effectiveness in offering potential long-term contraception for up to 10 years, the uptake of IUDs as emergency contraception remains extremely low at below 5 per cent in England.7
This is due to several factors, including poor public awareness, the incorrect perception that it is unsuitable for many women, more limited availability and accessibility, and the fact that many women are concerned about it being internally placed.8
Cost comparison of all three methods is difficult because emergency IUDs also offer long-term contraception, but a cost-effectiveness analysis of LNG and UPA has been published,9 looking at drug costs and the cost of unintended pregnancy (miscarriage, induced abortion and birth).
While UPA is currently more expensive per item than LNG, it has distinct advantages in its prolonged efficacy. The results of the cost analysis show that the incremental cost-effectiveness ratio (ICER), the cost of preventing one additional unintended pregnancy with UPA, is £311 compared with LNG when taken up to 120 hours post-UPSI.Comparing different time frames and costs the ICER ranges from £183 to £500.
However, all these costs are less than the estimated cost of unintended pregnancy (£948) or miscarriage, or the cost of induced abortion (£672). As UPA is nearly twice as effective as LNG, the incremental cost is worth paying and represents good value for the NHS.
That the cost-effectiveness of UPA compared with LNG is maintained at all time points within zero to 120 hours after UPSI should reassure clinicians that this newest form of emergency contraception is a valid option.
- Dr Jenkins is a GP in Bristol and medical director of Wings Medical Services.
1. Glasier A. Emergency postcoital contraception. N Engl J Med 1997; 337: 1058-64.
2. DoH. CMO's update35. January 2003. www.dh.gov.uk/prod_consum_dh/groups/dh_digitalassets/@dh/@en/documents/d igitalasset/dh_4065458.pdf
3. Task Force on Postovulatory Methods of Fertility Regulation: WHO. Randomised controlled trial of levonorgestrel versus the Yuzpe regimen of combined oral contraceptives for emergency contraception. Lancet 1998; 352: 428-33.
4. Glasier AF, Cameron ST, Fine PM, et al. Ulipristal acetate versus levonorgestrel for emergency contraception. Lancet 2010; 375: 555-62.
5. Fine P, Mathe H, Ginde S, et al. Ulipristal acetate taken 48-120 hours after intercourse for emergency contraception. Obstet Gynecol 2010; 115 (2 Pt 1): 257-63.
6. Wu S, Godfrey EM, Wojdyla D, et al. Copper T380A intrauterine device for emergency contraception. BJOG 2010; 117: 1205-10.
7. Health and Social Care Information Centre. NHS contraceptive services: England, 2009/10. October 2010. www.ic.nhs.uk/webfiles/publications/003_Health_Lifestyles/nhscontra0910/ NHS_Contraceptive_Services_England_2009_10.pdf
8. ESHRE Capri Workshop Group. Intrauterine devices and intrauterine systems. Hum Reprod Update 2008; 14: 197-208.
9. Thomas CM, Schmid R, Cameron S. Is it worth paying more for emergency hormonal contraception? The cost-effectiveness of ulipristal acetate versus levonorgestrel 1.5 mg. J Fam Plann Reprod Health Care 2010; 36: 197-201.