Mangling, Mishandling, and Misrepresentation of Science in the Plan B Debate (Part II)

Read Part I of "Mangling, Mishandling, and Misrepresentation of Science in the Plan B Debate"

In all my searching, I have found no studies that support the notion that Plan B acts as an abortifacient. The only two proven methods of action are thickening of the cervical fluid and prevention of ovulation. The manufacturer of Plan B states that it may interefere with implantation, but I strongly suspect that they’re just covering their ass…ets.

From a 2005 Population Council press release:

"Over the past few years, reproductive physiologist Horacio B. Croxatto of the Chilean Institute for Reproductive Medicine in Santiago, Chile, and his colleagues have studied the effects of levonorgestrel [the active ingredient in Plan B] on the reproductive cycles of female rats, monkeys, and humans. Croxatto and one of his study partners, biomedical researcher Vivian Brache of PROFAMILIA in Santo Domingo, Dominican Republic, are members of the ICCR."

"Croxatto and his colleagues exposed female rats to very high doses of levonorgestrel at various stages of their reproductive cycles, either before or after ovulation or before or after mating. The researchers found that levonorgestrel inhibited ovulation totally or partially, depending on the timing of treatment and the dose administered. However, the drug had no effect on fertilization or implantation. This research was published in the May 2003 issue of the journal Contraception."

"Next, Croxatto and his colleagues studied the effects of levonorgestrel given to Cebus monkeys either before ovulation or postcoitally. The reproductive cycle of each animal was monitored by ultrasound examination of the ovaries, vaginal smears, and measurements of blood hormone levels, in order to time the administration of levonorgestrel. The researchers found that, when given before ovulation, levonorgestrel was able to inhibit or postpone ovulation. Alternatively, when it was given after mating—at a time when fertilization was believed to have occurred (on the basis of previous monitoring)—the pregnancy rates observed were identical in cycles treated with levonorgestrel or with a placebo. This indicates that levonorgestrel did not interfere with any postfertilization process required for embryo implantation. This research was published in the June 2004 issue of the journal Human Reproduction."

"[…]Croxatto, Brache, and their colleagues studied the effects of levonorgestrel administered during this fertile preovulatory period of women’s menstrual cycles. The researchers used Plan B®, a levonorgestrel-containing emergency contraceptive product marketed in the United States and Canada."

"Twenty-nine women in Santiago and 29 women in Santo Domingo were enrolled in the study. All of the women were protected from pregnancy by tubal ligation or a nonhormonal intrauterine device. The study was randomized, double-blind, and placebo-controlled. Women were treated with either a placebo, a full dose of Plan B emergency contraception, or a half dose of the drug. They were followed over several menstrual cycles and, by the end of the study, each woman had received all three of these treatments, separated by resting cycles. The women were randomly assigned to receive the treatments at specific times during the fertile preovulatory period, according to the diameter of the leading ovarian follicle, as determined by ultrasound. The leading ovarian follicle is the structure that ruptures to release the egg."

"In 82 percent of Plan B–treated cycles, follicles failed to rupture within the five-day period following treatment (the maximum time span sperm would survive in the female reproductive tract), or there was some significant abnormality in ovulation. These conditions occurred in only 41 percent of placebo cycles. The rate of failed or abnormal ovulation that was observed with Plan B treatment is identical with the estimated efficacy rate of Plan B emergency contraception. Blood tests on these women indicated that Plan B influences ovulation by suppressing the surge of luteinizing hormone (LH), the hormone that triggers ovulation."

"’There is no doubt that fertilization would not have taken place in those women should they have had intercourse prior to treatment,’ says Croxatto. ‘We conclude that the effects exerted by Plan B, when it is taken before the onset of the LH surge, may fully explain the pregnancies averted by emergency contraception. Failure to affect the LH surge, because treatment was begun too late in the fertile preovulatory period, explains the 20 percent failure rate of this method. Our data presented in this paper suggest that emergency contraception using levonorgestrel works by disrupting ovulation, not by interfering with implantation.’ This research was published in the December 2004 issue of the journal Contraception."

Can I say definitively that Plan B does not interfere with implantation? No. Do I believe that the evidence against it acting in that manner is sufficient to call the drug contraceptive rather than abortifacient? Yes. If someone can provide research that shows a link between Plan B and spontaneous abortion, I’ll be glad to look at it. In the meantime, I’m with this guy:

"’The post-fertilization effect was purely a speculation that became truth by repetition,’ says Joe DeCook, MD, a retired OB/GYN and vice president of the American Association of Pro-Life Obstetricians and Gynecologists. ‘In our group the feelings are split. We say it should be each doctor’s own decision, because there is no proof.’"

So, what have we learned today?

  1. Breastfeeding prevents pregnancy via increased levels of prolactin, not progesterone.
  2. Prolactin does not affect the endometrium, so it does not affect implantation.
  3. There is no evidence that Plan B affects implantation.
  4. There is evidence that suggests that Plan B only prevents conception by either making cervical mucus hostile to sperm or preventing ovulation.
  5. Being liberal or conservative does not make one immune to stupidity or ignorance.
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About Funky Dung

Who is Funky Dung? 29-year-old grad student in Intelligent Systems (A.I.) at the University of Pittsburgh. I consider myself to be politically moderate and independent and somewhere between a traditional and neo-traditional Catholic. I was raised Lutheran, spent a number of years as an agnostic, and joined the Catholic Church at the 2000 Easter Vigil. Why Funky Dung? I haven't been asked this question nearly as many times as you or I might expect. Funky Dung is a reference to an obscure Pink Floyd song. On the album Atom Heart Mother, there is a track called Atom Heart Mother Suite. It's broken up into movements, like a symphony, and one of the movements is called Funky Dung. I picked that nickname a long time ago (while I was still in high school I think), shortly after getting an internet connection for the first time. To me it means "cool/neat/groovy/spiffy stuff/crap/shiznit", as in "That's some cool stuff, dude!" Whence Ales Rarus? I used to enjoy making people guess what this means, but I've decided to relent and make it known to all. Ales Rarus is a Latin play on words. "Avis rarus" means "a rare bird" and carries similar meaning to "an odd fellow". "Ales" is another Latin word for bird that carries connotations of omens, signs of the times, and/or augery. If you want to get technical, both "avis" and "ales" are feminine (requiring "rara", but they can be made masculine in poetry (which tends to breaks lots of rules). I decided I'd rather have a masculine name in Latin. ;) Yeah, I'm a nerd. So what? :-P Wherefore blog? It is my intention to "teach in order to lead others to faith" by being always "on the lookout for occasions of announcing Christ by word, either to unbelievers . . . or to the faithful" through the "use of the communications media". I also act knowing that I "have the right and even at times a duty to manifest to the sacred pastors [my] opinion on matters which pertain to the good of the Church, and [I] have a right to make [my] opinion known to the other Christian faithful, with due regard to the integrity of faith and morals and reverence toward [my and their] pastors, and with consideration for the common good and the dignity of persons." (adapted from CCC 904-907) Statement of Faith I have been baptized and confirmed in the name of the Father, Son and Holy Spirit. I, therefore, renounce Satan; I renounce all his works; I renounce all his allurements. I hold and profess all that is contained in the Apostles' Creed, the Niceno- Constantinopolitan Creed, and the Athanasian Creed. Having been buried with Christ unto death and raised up with him unto a new life, I promise to live no longer for myself or for that world which is the enemy of God but for him who died for me and rose again, serving God, my heavenly Father, faithfully and unto death in the holy Catholic Church. I am obedient to the Magisterium of the Catholic Church. That is, I promote and defend authentic Catholic Teaching and Faith in union with Christ and His Church and in union with the Holy Father, the Bishop of Rome, the Successor of St. Peter. Thanks be unto Thee, O my God, for all Thy infinite goodness, and, especially, for the love Thou hast shown unto me at my Confirmation. I Give Thee thanks that Thou didst then send down Thy Holy Spirit unto my soul with all His gifts and graces. May He take full possession of me for ever. May His divine unction cause my face to shine. May His heavenly wisdom reign in my heart. May His understanding enlighten my darkness. May His counsel guide me. May His knowledge instruct me. May His piety make me fervent. May His divine fear keep me from all evil. Drive from my soul, O Lord, all that may defile it. Give me grace to be Thy faithful soldier, that having fought the good fight of faith, I may be brought to the crown of everlasting life, through the merits of Thy dearly beloved Son, our Savior, Jesus Christ. Amen. Behind the Curtain: an Interview With Funky Dung (Thursday, March 03, 2005) I try to avoid most memes that make their way 'round the blogosphere (We really do need a better name, don't we?), but some are worth participating in. Take for instance the "interview game" that's the talk o' the 'sphere. I think it's a great way to get to know the people in neighborhood. Who are the people in your neighborhood? In your neighborhod? In your neigh-bor-hoo-ood...*smack* Sorry, Sesame Street flashback. Anyhow, I saw Jeff "Curt Jester" Miller's answers and figured since he's a regular reader of mine he'd be a good interviewer. Without further ado, here are my answers to his questions. 1. Being that your pseudonym Funky Dung was chosen from a Pink Floyd track on Atom Heart Mother, what is you favorite Pink Floyd song and why? Wow. That's a tuffy. It's hard to pick out a single favorite. Pink Floyd isn't really a band known for singles. They mostly did album rock and my appreciation of them is mostly of a gestalt nature. If I had to pick one, though, it'd be "Comfortably Numb". I get chills up my spine every time I hear it and if it's been long enough since the last time, I get midty-eyed. I really don't know why. That's a rather unsatisfying answer for an interview, so here are the lyrics to a Rush song. It's not their best piece of music, but the lyrics describe me pretty well.

New World Man He's a rebel and a runner He's a signal turning green He's a restless young romantic Wants to run the big machine He's got a problem with his poisons But you know he'll find a cure He's cleaning up his systems To keep his nature pure Learning to match the beat of the old world man Learning to catch the heat of the third world man He's got to make his own mistakes And learn to mend the mess he makes He's old enough to know what's right But young enough not to choose it He's noble enough to win the world But weak enough to lose it --- He's a new world man... He's a radio receiver Tuned to factories and farms He's a writer and arranger And a young boy bearing arms He's got a problem with his power With weapons on patrol He's got to walk a fine line And keep his self-control Trying to save the day for the old world man Trying to pave the way for the third world man He's not concerned with yesterday He knows constant change is here today He's noble enough to know what's right But weak enough not to choose it He's wise enough to win the world But fool enough to lose it --- He's a new world man...
2. What do you consider your most important turning point from agnosticism to the Catholic Church. At some point in '99, I started attending RCIA at the Pittsburgh Oratory. I mostly went to ask a lot of obnoxious Protestant questions. Or at least that's what I told myself. I think deep down I wanted desperately to have faith again. At that point I think I'd decided that if any variety of Christianity had the Truth, the Catholic Church did. Protestantism's wholesale rejection of 1500 years of tradition didn't sit well with me, even as a former Lutheran. During class one week, Sister Bernadette Young (who runs the program) passed out thin booklet called "Handbook for Today's Catholic". One paragraph in that book spoke to me and I nearly cried as I read it.
"A person who is seeking deeper insight into reality may sometimes have doubts, even about God himself. Such doubts do not necessarily indicate lack of faith. They may be just the opposite - a sign of growing faith. Faith is alive and dynamic. It seeks, through grace, to penetrate into the very mystery of God. If a particular doctrine of faith no longer 'makes sense' to a person, the person should go right on seeking. To know what a doctrine says is one thing. To gain insight into its meaning through the gift of understanding is something else. When in doubt, 'Seek and you will find.' The person who seeks y reading, discussing, thinking, or praying eventually sees the light. The person who talks to God even when God is 'not there' is alive with faith."
At the end of class I told Sr. Bernadette that I wanted to enter the Church at the next Easter vigil. 3. If you were a tree what kind of, oh sorry about that .. what is the PODest thing you have ever done? I set up WikiIndex, a clearinghouse for reviews of theological books, good, bad, and ugly. It has a long way to go, but it'll be cool when it's finished. :) 4. What is your favorite quote from Venerable John Henry Newman? "Ten thousand difficulties do not make one doubt." 5. If you could ban one hymn from existence, what would it be? That's a tough one. As a member of the Society for a Moratorium on the Music of Marty Haugen and David Haas, there are obviously a lot of songs that grate on my nerves. If I had to pick one, though, I'd probably pick "Sing of the Lord's Goodness" by Ernie Sands.

18 thoughts on “Mangling, Mishandling, and Misrepresentation of Science in the Plan B Debate (Part II)

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  6. Purple_Kangaroo

    So am I understanding correctly that Plan B only works if the woman has not ovulated before she takes the pill? If it works only by preventing ovulation and inhibiting fertilization, it would have no effect at all in most cases.

    In other words, if you take plan B 72 hours after having unprotected intercourse, it will have no effect whatsoever except in the rare situation in which sperm have survived more than 72 hours AND ovulation has not taken place at any time in the few days before or the 3 days after having sex. Ovulation would have to take place after the 72 hours is over but before the sperm die for Plan B to be any more effective than no contraception at all.

    If that’s the case, then Plan B must be extremely ineffective at preventing pregnancy. I don’t see how the manufacturer’s claim that “treatment [with Plan B] initiated within 72 hours after unprotected intercourse reduces the risk of pregnancy by at least 75%” can possibly be true if it only acts to prevent ovulation and/or inhibit fertilization.

  7. Funky Dung

    Part of the problem is that ovulation is often predicted as 14 days after the start of menses – a terribly inaccurate approximation. Incorrect identification of ovulation could easily lead to incorrect an incorrect expectation of pregnancies and the prevention thereof.

  8. Purple_Kangaroo

    Funky Dung, I don’t think incorrect identification of ovulation would affect something like the Plan B study.

    The only way the expected time of ovulation would even have an effect is if the researchers purposely (and successfully) made the study participants have intercourse 72 hours or more before ovulation happened, while at the same time somehow making the sperm survive more than 72 hours. That would be a really ineffective and dishonest way to prove the efficacy of a birth control method, since most women taking Plan B won’t be timing intercourse to take place exactly 72 hours or more before ovulation.

    To put it simply: For Plan B to work only in the way you are suggesting, the act of intercourse would always have to happen 72 hours or more before egg and sperm actually met. That is simply not going to be the case in that large a percentage. The group taking Plan B starting 72 hours after intercourse had a 75% lower rate of pregnancy than the control group. It seems nothing short of ridiculous to suggest that upwards of 75% of all pregnancies are not fertilized until 72 hours or more after the act of intercourse resulting in the pregnancy.

    The claim that Plan B does not inhibit implantation would require that fully 75% of the expected pregnancies were not fertilized until 72 hours or more after the act of intercourse. Sperm don’t usually live that long, for one thing, and an egg only lives for 24 hours after ovulation if unfertilized by that point.

    For a 75% success rate of birth control initiated 72 hours after intercourse, either Plan B would have to work by some method other than simply inhibiting ovulation/fertilization, or the statistics would seem to have been skewed or misrepresented somehow to make Plan B look more effective than it really is.

  9. Funky Dung

    This was a large study from the WHO involving women from 21 different countries. In this study, ovulation was determined by adding 14 days to the last period the subjects had. As anyone knows who have attempted to determine their own ovulation for fertility or for natural family planning, there is a wide variation in the moment of ovulation within a particular cycle. This is why change in temperature and changes in the quality of mucous are used in NFP to determine the naturally occurring fertility cycles. The method used by the women in the study cited is known to be quite inaccurate. For this reason, we would expect a significant portion of women who were placed in the post-ovulation group to actually be in the pre-ovulation or -ovulation group. In other words, there is ample reason to believe that the “reduction” of pregnancies from 10 to 2 in the “post-ovulatory” phase was the result of some of those women being in the pre-ovulatory or ovulatory phase of their cycle.

    Plan B EC: Does it Work if Taken After Ovulation?

  10. Purple_Kangaroo

    So it sounds like the the 75% rate may be only that 75% of pregnancies that would have been fertilized after 72 hours post-coitus are prevented by Plan B? That would make the “typical use” rate of efficacy would be far below 75%, wouldn’t it? I need to do a little research, I guess. The percentage of pregnancies that are fertilized later than 72 hours after coitus would be an important figure to know in calculating the true rate of efficacy.

    I’d sure like to see the entire text of some of these studies, rather than just the summaries. Do you know if they’re freely available online anywhere?

  11. Funky Dung

    The effectiveness of Plan B is reported to be somewhere between 90 and 75% in stopping an unintended pregnancy. If this is true, it seems impossible that it could work via a purely anti-ovulatory action. As Steve states here, the most important question to ask would be when did a woman ovulate. If Plan B is taken after a woman ovulates, and it contributes to the 75% effectiveness, then it must work at least part of the time via a post-fertilization event.

    If, on the other hand, Plan B works through predominantly anti-ovulatory actions, its effectiveness would be expected to be less than 75%. What does the data support? If one looks at some of the more recent studies, it is reasonable to conclude that the effectiveness of EC is significantly less than 75%.

    Plan B EC: What is its Real Effectiveness?

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