3659795

38

http://linkedlifedata.com/resource/pubmed/keyword/Abortifacient Agents, http://linkedlifedata.com/resource/pubmed/keyword/Abortion, Drug Induced, http://linkedlifedata.com/resource/pubmed/keyword/Abortion, Induced, http://linkedlifedata.com/resource/pubmed/keyword/Biology, http://linkedlifedata.com/resource/pubmed/keyword/CORPUS LUTEUM HORMONES, http://linkedlifedata.com/resource/pubmed/keyword/Carboxylic Acids, http://linkedlifedata.com/resource/pubmed/keyword/Clinical Research, http://linkedlifedata.com/resource/pubmed/keyword/Contraception, http://linkedlifedata.com/resource/pubmed/keyword/Contraceptive Agents, http://linkedlifedata.com/resource/pubmed/keyword/Contraceptive Agents, Female, http://linkedlifedata.com/resource/pubmed/keyword/Contraceptive Agents, Postcoital, http://linkedlifedata.com/resource/pubmed/keyword/Contraceptive Methods, http://linkedlifedata.com/resource/pubmed/keyword/Economic Factors, http://linkedlifedata.com/resource/pubmed/keyword/Endocrine System, http://linkedlifedata.com/resource/pubmed/keyword/Estrogens, http://linkedlifedata.com/resource/pubmed/keyword/Family Planning, http://linkedlifedata.com/resource/pubmed/keyword/Fertility Control, Postcoital, http://linkedlifedata.com/resource/pubmed/keyword/Fertility Control, Postconception, http://linkedlifedata.com/resource/pubmed/keyword/Hormone Antagonists, http://linkedlifedata.com/resource/pubmed/keyword/Hormones, http://linkedlifedata.com/resource/pubmed/keyword/Ingredients And Chemicals, http://linkedlifedata.com/resource/pubmed/keyword/Iud, http://linkedlifedata.com/resource/pubmed/keyword/Organic Chemicals, http://linkedlifedata.com/resource/pubmed/keyword/PROGESTERONE, http://linkedlifedata.com/resource/pubmed/keyword/PROSTAGLANDINS, http://linkedlifedata.com/resource/pubmed/keyword/Physiology, http://linkedlifedata.com/resource/pubmed/keyword/Progestational Hormones, http://linkedlifedata.com/resource/pubmed/keyword/Reproductive Control Agents, http://linkedlifedata.com/resource/pubmed/keyword/Research And Development, http://linkedlifedata.com/resource/pubmed/keyword/Research Methodology, http://linkedlifedata.com/resource/pubmed/keyword/TECHNOLOGY

http://linkedlifedata.com/resource/pubmed/journal/0404334

http://linkedlifedata.com/resource/pubmed/chemical/Contraceptives, Postcoital, http://linkedlifedata.com/resource/pubmed/chemical/Contraceptives, Postcoital, Hormonal, http://linkedlifedata.com/resource/pubmed/chemical/Estrogens, http://linkedlifedata.com/resource/pubmed/chemical/Progesterone, http://linkedlifedata.com/resource/pubmed/chemical/Progestins, http://linkedlifedata.com/resource/pubmed/chemical/Prostaglandins

Sep

pubmed-author:CouzinetBB, pubmed-author:SchaisonGG

21

NLM

2285-92

PIP: The term "pregnancy interception" covers all fertility control methods that interfere with implantation of the fertilized egg, either by inhibiting its transport or implantation or by eliminating the already implanted blastocyst. A few researchers beginning in 1960 used high doses of estrogen in the immediate postovulatory period to prevent implantation. It was discovered that administration had to occur soon after coitus to be effective. Estrogens were administered orally for 5 days beginning in the 72 hours following unprotected intercourse in the ovulatory phase. Secondary effects were common: vomiting in 40% of cases, menometrorrhagia in 30%, and almost constant breast discomfort. About 10% of pregnancies in case of failure of the method were ectopic. The mechanism of action is still not understood. A combined treatment of 50 mcg ethinyl estradiol and a 19-norsteroid progestin has been used since 1975. It must be administered in the 48 hours following coitus and repeated 12 hours later. The duration of treatment and quantity of hormones are significantly reduced, but the secondary effects are similar to those of estrogens used alone, and the failure rate is 2%. Some progestins can also be used alone. IUD insertion up to 7 days after the unprotected intercourse has a contragestive effect, but the risk of infection is considerable and 3% of patients develop endometritis. The risk of secondary sterility discourages use of the method, especially in nulliparas. The prostaglandins E and F are effective in early pregnancy termination, but their side effects considerably limit their use. The average duration of bleeding is acceptable, but prostaglandins cause very painful uterine contractions in 30-40% of cases. Gastrointestinal secondary effects often require termination of treatment. The recent synthesis and use of the antiprogesterone compound RU-486 offers real promise for a widely usable contragestive method. Progesterone is indispensable for the continuation of pregnancy, and inhibiting its action on the endometrium interrupts pregnancy. An antiprogesterone acts by competing directly with progesterone at the target cells. The antiprogesterone RU-486 also has dose-dependent luteolytic and antigonadotropic effects whose mechanisms are not completely understood. Clinical trials have proven the innocuity of RU-486, and its efficacy of about 90% will undoubtedly be improved. Interruption of early pregnancy is a major indication for RU-486. The duration of the pregnancy appears to be the determining factor in the percentage of success, but most researchers have had failure rates of 15% even in pregnancies of less than 5 weeks. Possible heavy bleeding or failure in case of ectopic pregnancy indicate the need for medical surveillance. A different route of administration and combination with a small dose of prostaglandin would undoubtedly raise the success rate. RU-486 may have more promise as a post-coital agent, and may potentially be the basis for development of a once-a-month pill.

1987

Journal Article, English Abstract