Monday, March 18, 2019

Scientific basis for morning after pill abortifacient

Miscellaneous data indicating “morning-after” pill abortifacient

Data 1

Levonorgestrel has only a limited effect on preventing ovulation( less than 15%), even when deliberately administered just before the LH surge. (1,2).  In one study, 361 peri-ovulatory women took levo-norgestrel 0.75mg after intercourse.  Using basal body temperature analysis, only 14.4% showed ovulatory inhibition (3).

$11)      Shi YE, Zheng SH, Shu Yhm He CH, Yu PP, Fortherby K, Pharmaco-kinetic study of levonorgestrel used as a postciotal contraceptive.  Contraception 1988; 37 (4) 359-369

$12)      Hapangama D, Glasier AF, Baird DT.  The effects of peri-ovulatory administration of levo-norgestrel on the menstrual cycle Contraception 2001;63:123-129

$13)      He CH, Shi YE, Xu JQ, VanLook PF, A multicentre clinical trial on two types of levonorgestrel tablets administered for postcoital contraception.  Int J Gynaecol Obstet 1991; 36 (1) 438

Cited in  Dr Philip Howard

Data 2

Patrick Yeung Jr. and co-authors explain that levo-norgestrel "interferes with the normal development and function of the corpus luteum; a dysfunctional corpus luteum then leads to an impaired endometrium [wall of the uterus] that interferes with embryonic implantation."   They argue that "no evidence exists to contradict this interceptive effect" and suggest that "levonorgestrel is estimated to act as an abortifacient 3%-13% of the time" when taken immediately prior to ovulation(1)

$1(1)   Yeung et al., “Argument Against the Use of Levonorgestrel in Cases of Sexual Assault,”Catholic Health Care Ethics: A Manual for Practitioners, Ed. Edward J.Furton, (Philadelphia: 2009), 144.

Data 3

Levonorgestrel emergency contraception: a joint analysis of effectiveness and mechanism of action
Fertility and Sterility, Volume 88, Issue 3, September 2007, Pages 565-571

Abstract: 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 modelled 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. Setting Combined data from multiple clinical studies, patient(s) Simulation models,  Intervention(s) and  Disruption of ovulation.

Main Outcome Measure(s): Effectiveness in the form of proportion of pregnancies prevented.

Result(s): With disruption of ovulation alone, the potential effectiveness of levonorgestrel EC ranged from 49% (no delay) to 8% (72-hour delay). With complete inhibition of fertilization before the day of ovulation, the potential effectiveness of levonorgestrel EC ranged from 90% (no delay) to 16% (72-hour delay).

Conclusion(s) The gap between effectiveness of levonorgestrel EC estimated from clinical studies and what can be attributed to disruption of ovulation may be explained by overestimation of actual effectiveness and supplementary mechanisms of action, including post-fertilization effects. Additional data with follicular ultrasound and precise measures of delay between intercourse and EC administration would yield greater insight into effectiveness and mechanisms of action.

Data 4

Experts confirm abortifacient potential of morning-after pill.

News report.

CNA STAFF, May 25, 2007 / 11:33 am (CNA).- The most recent scientific study on Levonorgestrel, the essential component of the “morning-after pill” or “emergency contraceptive,” confirms that the drug does indeed have a third effect on users, which consists in preventing the implantation of a fertilized ovum in the womb of the mother. 

The promoters of the drug in Latin America, where most countries have laws against abortion, have argued that the there is no scientific basis for the “third effect,” and that therefore the drug should be legalized.  Dr. Horacio Croxatto, professor at the Chilean Institute of Reproductive Medicine, said in 2006 that the morning-after pill “is not abortifacient because it only prevents pregnancy by stopping ovulation.”

Nevertheless, the most recent study (2007) by Doctors Mikolajczyk and Stanford of the Department of Medicine in Public Health of the University of Bielefeld (Germany) clearly indicates that the pill’s “real effect” includes mechanisms that prevent implantation.

Published by the magazine Fertility and Sterility, the study used data from multiple clinical studies with advanced mathematical models and concluded that if emergency contraception only inhibited ovulation its true effectiveness would only be in a range of 8-49 percent.  If it acted before ovulation and if it inhibited ovulation completely, its true effectiveness would be between 16-90 percent.  The rest of the pill’s effectiveness consists in its anti-implantation mechanisms, which cause an abortion

Mode of Action Levonelle One Step       miscellaneous notes

(Patient Information leaflet      Bayer Schering Pharma

“Levonelle One Step is thought to work by:

  • Stopping your ovaries from releasing an egg;
  • preventing sperm from fertilising any egg you may have already released;
  • stopping a fertilised egg from attaching itself to your womb lining”

COMMENT: Note that Cervical mucus thickening only arises 24 hours after administration! Sperm appear in the uterus within 30 mins .

 cf Cyclic changes of cervical mucus in normal and progestin-treated women.  Fertil Steril. 1966;17:63  cited in 

Proof of an abortive effect!    Fertilisation can take place within 2-3 hours!!  Why is it then that the manufacturer recommends it to be used within 72 hours after intercourse?!!  Because they know the newly conceived life -  if fertilisation has taken place - takes 5-7 days before implantation!!

“The precise mode of action of Levonelle 1500 is not known.    

At the recommended regimen, levonorgestrel is thought to work mainly by preventing ovulation and fertilisation if intercourse has taken place in the preovulatory phase, when the likelihood of fertilisation is the highest. It may also cause endometrial changes that discourage implantation. Levonelle 1500 is not effective once the process of implantation has begun”

Results from a recent clinical study (Lancet 2002; 360: 1803-1810) showed that a 1500 microgram single dose of Levonelle One Step (taken within 72 hours of unprotected intercourse) prevented 84% of expected pregnancies (compared with 79% when the two 750 microgram tablets were taken 12 hours apart).