Emergency contraception: A real need for a second chance – Epidemiological evidence
(14th World Congress of Gynecological Endocrinology – March 4-7 2010)
Levonorgestrel as an emergency contraceptive (LNG-EC) is used world –wide with clinical success. For maximal effectiveness it should be administered within 72 hrs after unprotected intercourse. A single dose of 1.5 mg of Levonorgestrel or divided 12 hrs apart effectively prevents an undesired pregnancy. Investigations on the mechanisms of action have clearly revealed that LNG-EC administration during early-mid proliferative phase inhibits or delays the ovulation process, while none endometrial morphological alterations are observed if the drug is administered during the periovulatory stage or early luteal phase. more
1) Hum Reprod. 2009 Aug;24(8):1862-9.
BACKGROUND: Misoprostol is widely used in obstetrics and gynaecology for medical abortion, cervical priming and induction of labour. To aid the design of effective and safe regimens, we have investigated the pharmacokinetic parameters after the vaginal or sublingual administration of repeated doses of 400 microg of misoprostol. more
1) Fertil Steril. 2007 Sep;88(3):565-71.
Mikolajczyk RT, Stanford JB.
OBJECTIVE: To model the effectiveness that can be obtained if levonorgestrel-only emergency contraception (EC) acts only through disrupting ovulation, in relation to other effects that may occur before or after fertilization and accounting for delays in administration. DESIGN: We modeled follicular growth as a function of follicular size, using known day-specific probabilities of conception and known disruption of ovulation by levonorgestrel-only EC, to estimate the expected effectiveness of EC. more
Emergency contraception is contraception provided after an unprotected intercourse. A series of study conducted by the World Health Organization showed that (a) levonorgestrel is more effective and better tolerated than the Yuzpe regimen (which consists of two doses of combined oral contraceptive pills given at 12 hour interval)1,2, (b) and the administration of a single dose of levonorgestrel is as effective as two doses of 0.75 mg given 12 hours apart or a single dose of 10 mg of mifepristone3. Since levonorgestrel is more widely available than mifepristone, a single dose of 1.5 mg of levonorgestrel has become the regimen of choice for emergency contraception in most countries. more