hormonal method failures (e.g. missed oral contraceptive with no back up method used, late long-acting injection).
There are 3 kinds of emergency contraception available: combined hormone emergency contraceptive pills (combined ECP), progestin-only emergency contraceptive pills (progestin only ECP), and emergency insertion of a copper-T IUD. These methods will not stop a pregnancy which has already begun, but can stop conception from happening if taken in the few days following unprotected sex.
All methods must be used within 5 days of a risk, though ECPs are more effective the earlier they are taken and should be taken as soon after unprotected intercourse as possible. We don't know exactly how ECPs work, but it is thought that they inhibit or delay ovulation, or possibly prevent implantation by changing the lining of the uterus. Other possibilities include interference with some of the ovaries' functioning, thickening of the cervical mucus, and changes in the tubal transport of sperm or egg.
Hormonal methods are available by prescription only and can be obtained from: physicians, walk in clinics, youth clinics, free clinics, Planned Parenthood clinics, certain pharmacies with authorized pharmacists, as well as hospital emergencies. Emergency IUD insertion is done by a physician trained in IUD insertion. Emergency contraception providers can also be found by calling Reproductive Health Technology Project at 1-888-668-2528 or on the net at http://ec.princeton.edu/providers/index.html#Canada
1. Combined ECP (Formerly called the Morning After Pill)
With this method, each of the 2 doses contain 100mg of ethinyl estrodiol & 0.50mg of levonorgestrel. The first dose is taken within 5 days of the risk, with the second dose taken 12 hours after the first. As this method causes nausea in 50% of women and vomiting in 20%, it can be given with anti-nausea medication, such as dimenhydrinate (Gravol®). If vomiting occurs within one hour after taking a dose, the dose may need to be repeated. A woman who takes ECP within 72 hours can expect her period to arrive within 3 weeks.
Use of this pill cuts the chance of pregnancy by 75%. This does not mean that 25% of women using ECPs will become pregnant. Rather, if 100 women had unprotected intercourse once during the second or third week of their cycle, about 8 would become pregnant; following treatment with ECPs, only 2 would become pregnant - a 75% reduction.
2. Progestin-only ECP
Approved in 2000, progestin-only ECP uses progesterone hormone only and is marketed under the name Plan B®. Progestin-only oral contraceptives can also be used in the correct dosage. The treatment schedule is one 0.75 mg dose of levonorgestrel within 72 hours after unprotected intercourse, and a second 0.75 mg dose 12 hours after the first dose. The first dose is taken within 5 days of the risk, with the second dose 12 hours later. Nausea and vomiting are far less common, 23% and 6% respectively, with progestin-only ECPs.
Use of progestin-only ECPs reduces the risk of pregnancy by about 89%. This does not mean that 11% of women will become pregnant. Rather, if 100 women have unprotected intercourse once during the second or third week of their menstrual cycle, about 8 will become pregnant. If those same women had used progestin-only ECPs, only one would have become pregnant (an 89 percent reduction). Therapy is more effective the earlier it is initiated within the 5-day window.
3. Copper IUD
The copper-T intrauterine device (IUD) can be inserted up to five days after unprotected intercourse to prevent pregnancy. The only one available in Canada is the Nova-Tä. The way it works is thought to be through the introduction of something foreign (the IUD) reacting within the woman's uterus and upper reproductive tract. This is toxic to sperm and egg and interferes with implantation or transport.
Insertion of a copper-T IUD is much more effective than use of either type of ECP, reducing the risk of pregnancy following unprotected intercourse by more than 99%. Women at risk for STDs because they or their partners have other sexual partner(s) may not be good candidates.
