Analysis of information sources in references of the Wikipedia article "ليفونورغيستريل" in Arabic language version.
Emergency postcoital contraception
Levonorgestrel
Mechanism and efficacy
NorLevo works by stopping your ovaries from releasing an egg. It cannot stop a fertilized egg from attaching to the womb.
{{استشهاد ويب}}: الوسيط |الفصل= تم تجاهله (مساعدة) والوسيط |مسار= غير موجود أو فارع (مساعدة)Levonorgestrel-only emergency contraceptive pills:
• Interfere with the process of ovulation;
• May possibly prevent the sperm and the egg from meeting.
Implications of the research:
• Inhibition or delay of ovulation is LNG ECPs principal and possibly only mechanism of action.
• Review of the evidence suggests that LNG-ECs cannot prevent implantation of a fertilized egg. Language on implantation should not be included in LNG ECP product labeling.
• The fact that LNG-ECs have no demonstrated effect on implantation explains why they are not 100% effective in preventing pregnancy, and are less effective the later they are taken. Women should be given a clear message that LNG-ECs are more effective the sooner they are taken.
• LNG ECPs do not interrupt a pregnancy (by any definition of the beginning of pregnancy). However, LNG ECPs can prevent abortions by reducing unwanted pregnancies.
How does EC work?
In 2002, a judicial review ruled that pregnancy begins at implantation, not fertilisation.8 The possible mechanisms of action should be explained to the patient as some methods may not be acceptable, depending on individual beliefs about the onset of pregnancy and abortion.
Copper-bearing intrauterine device (Cu-IUD). Copper is toxic to the ovum and sperm and thus the copper-bearing intrauterine device (Cu-IUD) is effective immediately after insertion and works primarily by inhibiting fertilisation.9–11 A systematic review on mechanisms of action of IUDs showed that both pre- and postfertilisation effects contribute to efficacy.11 If fertilisation has already occurred, it is accepted that there is an anti-implantation effect,12,13
Levonorgestrel (LNG). The precise mode of action of levonorgestrel (LNG) is incompletely understood but it is thought to work primarily by inhibition of ovulation.16,17
Ulipristal acetate (UPA). UPA’s primary mechanism of action is thought to be inhibition or delay of ovulation.2
{{استشهاد بكتاب}}: تحقق من التاريخ في: |تاريخ الوصول= (مساعدة)NorLevo works by stopping your ovaries from releasing an egg. It cannot stop a fertilized egg from attaching to the womb.
{{استشهاد ويب}}: الوسيط |الفصل= تم تجاهله (مساعدة) والوسيط |مسار= غير موجود أو فارع (مساعدة)NorLevo works by stopping your ovaries from releasing an egg. It cannot stop a fertilized egg from attaching to the womb.
{{استشهاد ويب}}: الوسيط |الفصل= تم تجاهله (مساعدة) والوسيط |مسار= غير موجود أو فارع (مساعدة){{استشهاد ويب}}: الوسيط |الفصل= تم تجاهله (مساعدة) والوسيط |مسار= غير موجود أو فارع (مساعدة)NorLevo works by stopping your ovaries from releasing an egg. It cannot stop a fertilized egg from attaching to the womb.
{{استشهاد ويب}}: الوسيط |الفصل= تم تجاهله (مساعدة) والوسيط |مسار= غير موجود أو فارع (مساعدة){{استشهاد ويب}}: صيانة الاستشهاد: أسماء متعددة: قائمة المؤلفين (link){{استشهاد بكتاب}}: تحقق من التاريخ في: |تاريخ الوصول= (مساعدة)How does EC work?
In 2002, a judicial review ruled that pregnancy begins at implantation, not fertilisation.8 The possible mechanisms of action should be explained to the patient as some methods may not be acceptable, depending on individual beliefs about the onset of pregnancy and abortion.
Copper-bearing intrauterine device (Cu-IUD). Copper is toxic to the ovum and sperm and thus the copper-bearing intrauterine device (Cu-IUD) is effective immediately after insertion and works primarily by inhibiting fertilisation.9–11 A systematic review on mechanisms of action of IUDs showed that both pre- and postfertilisation effects contribute to efficacy.11 If fertilisation has already occurred, it is accepted that there is an anti-implantation effect,12,13
Levonorgestrel (LNG). The precise mode of action of levonorgestrel (LNG) is incompletely understood but it is thought to work primarily by inhibition of ovulation.16,17
Ulipristal acetate (UPA). UPA’s primary mechanism of action is thought to be inhibition or delay of ovulation.2
Can LNG ECPs cause an abortion?
LNG ECPs do not interrupt an established pregnancy or harm a developing embryo.15 The evidence available to date shows that LNG ECP use does not prevent a fertilized egg from attaching to the uterine lining. The primary mechanism of action is to stop or disrupt ovulation; LNG ECP use may also prevent the sperm and egg from meeting.16
Levonorgestrel-only emergency contraceptive pills:
• Interfere with the process of ovulation;
• May possibly prevent the sperm and the egg from meeting.
Implications of the research:
• Inhibition or delay of ovulation is LNG ECPs principal and possibly only mechanism of action.
• Review of the evidence suggests that LNG-ECs cannot prevent implantation of a fertilized egg. Language on implantation should not be included in LNG ECP product labeling.
• The fact that LNG-ECs have no demonstrated effect on implantation explains why they are not 100% effective in preventing pregnancy, and are less effective the later they are taken. Women should be given a clear message that LNG-ECs are more effective the sooner they are taken.
• LNG ECPs do not interrupt a pregnancy (by any definition of the beginning of pregnancy). However, LNG ECPs can prevent abortions by reducing unwanted pregnancies.
NorLevo works by stopping your ovaries from releasing an egg. It cannot stop a fertilized egg from attaching to the womb.
{{استشهاد ويب}}: الوسيط |الفصل= تم تجاهله (مساعدة) والوسيط |مسار= غير موجود أو فارع (مساعدة){{استشهاد ويب}}: صيانة الاستشهاد: أسماء متعددة: قائمة المؤلفين (link)Can LNG ECPs cause an abortion?
LNG ECPs do not interrupt an established pregnancy or harm a developing embryo.15 The evidence available to date shows that LNG ECP use does not prevent a fertilized egg from attaching to the uterine lining. The primary mechanism of action is to stop or disrupt ovulation; LNG ECP use may also prevent the sperm and egg from meeting.16
Mechanism of action
Copper-releasing IUCs
When used as a regular or emergency method of contraception, copper-releasing IUCs act primarily to prevent fertilization. Emergency insertion of a copper IUC is significantly more effective than the use of ECPs, reducing the risk of pregnancy following unprotected intercourse by more than 99%.2,3 This very high level of effectiveness implies that emergency insertion of a copper IUC must prevent some pregnancies after fertilization.
Emergency contraceptive pills
To make an informed choice, women must know that ECPs—like the birth control pill, patch, ring, shot, and implant,76 and even like breastfeeding77—prevent pregnancy primarily by delaying or inhibiting ovulation and inhibiting fertilization, but may at times inhibit implantation of a fertilized egg in the endometrium. However, women should also be informed that the best available evidence indicates that ECPs prevent pregnancy by mechanisms that do not involve interference with post-fertilization events.
ECPs do not cause abortion78 or harm an established pregnancy. Pregnancy begins with implantation according to medical authorities such as the US FDA, the National Institutes of Health79 and the American College of Obstetricians and Gynecologists (ACOG).80
Ulipristal acetate (UPA). One study has demonstrated that UP can delay ovulation.81... Another study found that UPA altered the endometrium, but whether this change would inhibit implantation is unknown.82
p. 122:
Progestin-only emergency contraceptive pills. Early treatment with ECPs containing only the progestin levonorgestrel has been show to impair the ovulatory process and luteal function.83–87
p. 123:
Combined emergency contraceptive pills. Several clinical studies have shown that combined ECPs containing ethinyl estradiol and levonorgestrel can inhibit or delay ovulation.107–110
How does EC work?
In 2002, a judicial review ruled that pregnancy begins at implantation, not fertilisation.8 The possible mechanisms of action should be explained to the patient as some methods may not be acceptable, depending on individual beliefs about the onset of pregnancy and abortion.
Copper-bearing intrauterine device (Cu-IUD). Copper is toxic to the ovum and sperm and thus the copper-bearing intrauterine device (Cu-IUD) is effective immediately after insertion and works primarily by inhibiting fertilisation.9–11 A systematic review on mechanisms of action of IUDs showed that both pre- and postfertilisation effects contribute to efficacy.11 If fertilisation has already occurred, it is accepted that there is an anti-implantation effect,12,13
Levonorgestrel (LNG). The precise mode of action of levonorgestrel (LNG) is incompletely understood but it is thought to work primarily by inhibition of ovulation.16,17
Ulipristal acetate (UPA). UPA’s primary mechanism of action is thought to be inhibition or delay of ovulation.2