Emergency Contraception : a Rational Approach

A request for the ‘morning after pill’ presents the GP with the challenge of making appropriate decisions based on a number of criteria. Dr Louise Newson, a GP and specialist writer on women’s health, explores the issues and the options faced when prescribing emergency contraception:

 

Clinical case study

Lisa is a 17 year old girl who comes to see you one Monday morning asking for emergency contraception. She had unprotected sex on Saturday night. She tried the oral contraceptive pill in the past but found that she kept forgetting to take it. However, she has been recently diagnosed as having epilepsy, for which she takes carbamazepine, and has been told by her friends that she cannot take emergency contraception as it interferes with her anti-epilepsy medication. She comes to see you for advice. How should you advise her?

Emergency contraception (EC) – also referred to as postcoital contraception and the ‘morning after pill’ – is defined as the use of contraception to prevent a pregnancy following intercourse. There are currently three different methods that can be used in the UK: 

• Copper intrauterine contraceptive device (IUD)
• Levonorgestrel
• Ulipristal acetate
  

Indications for use of EC

The most common and obvious indication for EC is following intercourse when no contraception has been used and a pregnancy is not planned. It should be also given following rape or sexual assault. Other indications for EC use include: 

• Incorrect use of barrier methods
• Use of hormonal contraception when taking an enzyme-inducing drug (eg rifampicin) or in the 28 days after use
• Missing two or more combined oral contraceptive pills in the first week
• Not using barrier contraception within seven days of vomiting or diarrhoea when taking oral contraception
• Missing one or more progesterone-only pills or if it has been more than 36 hours since the last desogestrel-only pill
• If more than 14 weeks have elapsed since the last depot contraceptive injection
• If a change of contraceptive patch has been delayed by more than 48 hours
• If a contraceptive IUD has been removed without replacing another, if it has been expulsed or if the threads are missing

Note: If more than two pills have been missed during the last seven days of a packet of combined oral contraceptive (COC) pills then the next packet should be started without a pill-free week. EC is not needed for the first 21 days post partum.

Key considerations for the consultation

Various factors may need to be taken into consideration to determine whether EC is actually indicated and also the type of EC that is most suitable for each individual woman.
The following should be noted: 

• Menstrual history of patient
• Length of time since unprotected sexual intercourse (UPSI)
• Whether there have been any other episodes of UPSI in this cycle
• Type of contraception used, if any
• Previous use of any EC
• Medication history (including any OTC medications, e.g. St John’s wort)
• Any past relevant gynaecological history (e.g. pelvic in!ammatory disease)
• Current need for contraception  

Determining the precise timing of an ovulation in a woman is very difficult. The length of the luteal phase (ovulation to menstruation) is usually constant at 14 days, whereas the follicular phase is more variable. Conception is most likely to occur following UPSI on the day of ovulation or in the preceding 24 hours. The risk of pregnancy cannot be accurately determined from a self-reported cycle. Although the chances of pregnancy from a single act of intercourse in the first 3 days of the cycle is actually negligible, many healthcare professionals will still recommend EC if UPSI has occurred at this time.

Types of EC

Copper-bearing intrauterine device (Cu-IUD)

Copper is toxic to the ovum and sperm. The Cu-IUD works primarily by inhibiting fertilisation. A Cu-IUD should be !tted within the !rst 5 days (120 hours) following first UPSI in a cycle or within 5 days of the earliest estimated date of ovulation.3 The copper IUD is the most effective EC method and the only method to provide ongoing contraception if left in situ. Ideally an emergency IUD should be inserted at !rst presentation, but where this is not possibleoral EC can be given in the interim and then the woman advised to attend for insertion at the earliest appropriate time. The failure rate for use of the Cu-IUD used as emergency contraception is considerably lower than 1%. One large prospective observational cohort study has shown that the CU-T380A® IUD is very effective with no pregnancies reported in the !rst month after insertion among 1963 women (nulliparous and parous) who received it for the purpose of EC.4 The Cu-IUD may be removed following the next menstrual period if it is not required as long-term contraception. There is no evidence of effectiveness for using the levonorgestrel-releasing intrauterine system (LNG-IUS) as emergency contraception and so it should not be offered for this purpose.

Levonrgestrel (LNG)

LNG is taken as a single oral 1.5mg dose as soon possible after UPSI and is licensed for use for up to 72 hours following UPSI. Although the precise mode of action of levonorgestrel (LNG) is not fully understood, it appears to inhibit ovulation by preventing follicular rupture or causing luteal dysfunction.5 LNG can inhibit ovulation for 5–7 days, by which time any sperm in the reproductive tract will have become non-viable.6 Pregnancy rates with LNG are around 2-3% when used within 72 hours of UPSI. LNG is more effective if taken closer to the episode of UPSI.7 LNG can be taken more than once in a cycle if indicated. If women are taking liver enzyme-inducing drugs and do not want or cannot have a Cu-IUD then they can be given a double dose of 3mg LNG(although this is outside the product licence). The available evidence suggests that pregnancies occurring after LNG failure are not associated with any major congenital malformations, pregnancy complications or other adverse pregnancy outcomes.8

Ulipristal acetate (UPA)

UPA is taken as a single oral 30mg dose as soon as possible after UPSI and is licensed for emergency contraception up to 120 hours (5 days) following UPSI. Ulipristal’s primary mechanism of action is thought to be inhibition or delay of ovulation. The efficacy of UPA has been demonstrated up to 120 hours after UPSI and there is no apparent decline in ef!cacy within that time period.9 Pregnancy rates with ulipristal are around 1-2% when taken within 120 hours.10 The use of ulipristal has increased recently; one study has demonstrated that the use of this EC has increased to nearly 19%.11 Although there is currently a lack of evidence on the effect of UPA if inadvertently administered after implantation has occurred, there have been no associated adverse outcomes in the small numbers of inadvertent pregnancies that have been reported to date.12 UPA should not be given more than once in the same menstrual cycle. Women taking liver enzymeinducing drugs and also those taking dugs that increase the gastric pH (e.g. antacids, proton pump inhibitors) should not be offered UPA. The risk of pregnancy with UPA has been shown to be signi!cantly reduced compared with LNG.10

Common side effects

The most common side effect following IUD insertion is pain. Headache, nausea and altered bleeding patterns are common after taking both types of hormonal emergency contraception. Although vomiting is uncommon, all women should be advised to take another dose of EC if they vomit within 2 hours of taking LNG or within 3 hours of taking UPA.

Additional management

Current guidelines recommend that all women receiving EC should be offered testing for sexually transmitted infections (STIs) irrespective of age, relationship or ethnicity.1 HIV testing may also be appropriate for some women. Women should be made aware that any recently acquired infections may not be detected initially and so they may need to be retested after the appropriate window period. This depends on the infection; for example HIV testing may need to be repeated after 3 months. All women should be advised to perform a pregnancy test after at least 3 weeks if they feel pregnant or have not had a normal period following using EC. It is very important that all women are advised that the oral methods of emergency contraception are not a form of ongoing contraception.

Starting contraception

Although women often prefer to wait until a pregnancy is excluded before starting contraception, it may be appropriate in some cases to start contraception immediately (quick starting contraception). Some women prefer to start effective contraception promptly and it may be offered to those who are likely to have UPSI again in the same cycle. A method that has been quick started may be continued as an ongoing method of contraception or it may be used as a temporary ‘bridging’ method until pregnancy can be excluded and a longer-acting method initiated. This is usually in the form of the combined hormonal contraceptive (CHC), the progesterone only pill (POP) or the implant. The progesterone-only injectable should only be quick started after EC if other methods are not appropriate or not acceptable.

Continuing with contraception

If EC has been given because of missed pills, then women should restart their usual contraception as soon as possible. They will need to use additional precautions, such as condoms, for a period of up to 16 days, depending on the method of EC and ongoing contraception used, as shown below:
Following LNG: 7 days with CHC (9 for Qlaira); 2 days with POP
Following UPA: 14 days with CHC (16 for Qlaira); 9 days with POP

If a Cu-IUD is to be used for ongoing contraception, women should return for a follow-up visit following their !rst period (or 3–6 weeks) after insertion.

Advance prescriptions of EC

Although women may sometimes request an advance prescription of EC, this has not actually been shown to reduce pregnancy rates. It may, however, be appropriate for some women – for example those going on holiday or those solely relying on barrier methods of contraception. Many adolescents rely on condoms backed up by emergency contraception as their main method of contraception.13 Currently LNG is the only EC that is available free under Patient Group Directions at pharmacies and clinics to women under 24 years. It can also be bought over the counter.

Case Study: What next for Lisa?

Although Lisa’s friends are correct in that she should not be given ulipristal the options for EC for her are either having the Cu-IUD inserted or taking double dose of levororgestrel. The pros and cons of each choice should be discussed with her. Women who require EC while using liver enzyme-inducing anti-epiletic drugs should be advised that an IUD is the preferred option.

This consultaiton should also be used as an opportunity to discuss furture contraception with her. the most suitable contraception available to her is the progestogen-only injection. Although she could consider having either levonorgestrel-copper-bearing intrauterine device inserted these are not usually first choice methods for women of her age.

Although no specific interaction studies have been performed with the etonogestrel-only implant true failures have been reported in women also taking anti-epileptic drugs. The implant is not therefore recommended to women who are also taking carbamazepine. She should also be offered testing for any sexually transmitted infections. Whichever contraception she decides upon, she should also be advised to use condoms.

References

1 Faculty of Sexual and Reproductive Healthcare Clinical Guideline. Emergency Contraception. Clinical Effectiveness Unit. August 2011 (Updated January 2012) www.fsrh.org/pdfs/CEUguidanceEmergencyContraception11.pdf
2 Faculty of Sexual and Reproductive Healthcare Clinical Effectiveness Unit. Missed Pill Recommendations. May 2011. www.fsrh.org/pdfs/CEUStatementMissedPills.pdf
3 Cheng L, Che Y, Gülmezoglu AM. Interventions for emergency contraception. Cochrane Database Syst Rev. 2012 Aug 15;8:CD001324
4 Wu S, Godfrey EM, Wojdyla D, et al. Br J Obstet Gynaecol 2010;117:1205–1210.
5 Okewole IA, Arowojolu AO, Odusoga OL, et al. Contraception 2007;75:372–377
6 Noe G, Croxatto HB, Salvatierra AM, et al. Contraception 2010;81:414–420.
7 Fine P, Mathe H, Ginde S, et al. Obstet Gynecol 2010;115:257–263.
8 Zhang L, Chen J, Wang Y, et al. Hum Reprod 2009;24:1605–1611.
9 Richardson AR, Maltz FN. Clin Ther. 2012 Jan;34(1):24-36.
10 Glasier AF,#Cameron ST,#Fine PM, et al. Lancet 2010;375:555–562.
11 Baird AS. J Fam Plann Reprod Health Care. 2013 Apr 25.[Epub ahead of print] www.ncbi.nlm.nih.gov/pubmed/23620506
12 Brache V, Cochon L, Jesam C, et al. Hum Reprod 2010;25:2256–2263.
13 Apter D. Adolescent contraception. Endocr Dev. 2012;22:287–301.