Science of Love, Sex, and Babies

Are pheromones why the rhythm method doesn’t work?

Posted in news by jenapincott on August 2, 2009

Pregnancy_25_weeks For women not trying to get pregnant, life should be easy. Conception can only happen in the 12-24 hours after ovulation. Sure, sperm may last as many as 3-4 days in the genital tract, hanging around for the egg to arrive. But you’d think not having sex during the 4-5-day window would be sufficient to avoid mishaps. That’s what the rhythm method is — a natural form of birth control that relies on abstinence on fertile days.

But slips happen even among the most careful practitioners of the rhythm method. Some of this may have to do with women not keeping perfect track of their menstrual cycles or having naturally irregular cycles. (I discuss in BLONDES the evolutionary reasons why ovulation is hidden to both women and their partners.) The failure rate for rhythm method is 25 percent each year (with a perfect-use rate of 9 percent).

Why so high?

Another reason could be pheromones. The latest issue of my favorite journal, Medical Hypotheses, includes a submission that suggests that pheromones from men may cause an early ovulation in women. By invoking an early release of the egg — in advance of the expected fertile window — chances of fertilization are higher. As I mention in BLONDES, studies have the found that androstadienone, a testosterone-related compound found in men’s sweat, semen, and saliva, increases the amount of luteinizing hormone in women, which thereby triggering ovulation. It’s possible that high-testosterone men may be likelier to have this effect on their lovers. Their sweat smell alone may do the trick.

As I mentioned in an earlier post, there are other properties in semen that may also trigger early ovulation. For instance, seminal fluid contains follicle stimulating hormone (FSH) and luteinizing hormone (LH), which may coax the ovary to release an egg.

Despite the high failure rate, the Roman Catholic Chruch continues to promote the rhythm method, now renamed natural family planning (adding cervical mucus and temperature data to the regimen). Problem is, we don’t live in a clockwork universe, nor do we have clockwork bodies.

14 Responses

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  1. […] Are pheromones why the rhythm method doesn’t work? For women not trying to get pregnant, life should be easy. Conception can only happen in the 12-24 hours after ovulation. Sure, sperm may last as many as 3-4 days in the genital tract, hanging around for the egg to arrive. But you’d think not having sex during the 4-5-day window would be sufficient to avoid mishaps. That’s what the rhythm method is — a natural form of birth control that relies on abstinence on fertile days. […]

  2. sex said, on August 4, 2009 at 2:06 pm

    The fundamental take-away from this situation is that politics and religion should not and do not make good bedfellows. But the far right is intent on making this a ‘Christian’ nation. And whatever that means would be up to the latest ‘Divine Supreme Apostle’ who would decree the holy mandates to his subjects.

    Maybe Jimmy Swaggart will make a comeback and run for President; and he and Sarah could take a ride in his limo.

    As long as a large segment of voters continues to use religion and abortion as a litmus test for their vote, then we will contiue to send functionally schizophrenic politicians to Washington and to state legislatures, county courthouses, city halls local school boards. If you are not a ‘true believer’ it is really hard to live a lie. And money and sex will make a liar out of you every time – unless you have truly deluded yourself into believing what you thought you had to say to Aunt Ruth and the “Christians for High Office” political rally at the county fair.

    Reasonable educated people have sat on the sidelines for too long. Hopefully the exposure of the radical far right as a truly fringe group that could really be a danger to liberty in this country will rally the votes in upcoming elections. We can hope.

    • OLD Whig said, on August 31, 2009 at 10:45 pm

      SEX’s reply has nothing to do with the rhythm method, but is pretty much a mindless, meandering diatribe against religion. Since SEX thinks he/she is “educated,” let us look at the errors in his/her comments.First, what does seperation of church and state have to do with the (3%) of Catholic couples voluntarily using a natural method? Second,with over 265 different Christin denominations, SEX does not tell us how all these Christians would come up with the same doctrine to impose on us. Jimmy Swaggart is anti-Catholic, and Sarah palin is an ex-Catholic, so SEX should actually be grateful for these two leaders who will protect us from Catholicism. The left in America uses abortion as a litmus test, not only for their personal votes, but even when choosing judges. If Sonya Sotomayor had actually been a typical “Latina,” that is, opposed to abortion, those fawning, grinning, smirking Democratic senators would never have nominated her. But she is the Hispanic version of an “Uncle Tom,” and thus perfectly acceptable to the Democratic Party. In short, SEX is neither reasonable nor educated, but merely an idiot.

  3. Multiple Male Orgasm said, on December 11, 2009 at 2:22 am

    I am really surprised by the statistics. Are you sure about this 25%? No one would ever imagine it can be that high. I can confirm though that the risk exists at any moment of the cycle. My wife got pregnant after only one day after her period. What a surprise! Thank you for this very interesting post.

    Ricky

  4. Lissa said, on January 24, 2010 at 12:51 am

    Actually the church doesn’t promote the rhythm method. The most common natural family planning method is the fertility awareness system. If you google “fertility awareness” I’m sure you’ll find more information. The most common methods being the Billings Ovulation Method, the Creighton Model (or some combination of both.)

    There is also the Marquette Method of fertility awareness which avoids pregnancy using the Clearblue Easy fertility monitor. The 98-99% effective in avoiding pregnancy, when used correctly. Contraceptive pills are 99% effective, when used correctly. However birth control pills are only 92% effective with typical uses. This is comparable to the 90% efficacy of the Marquette Method, with typical use. (Source: Trussell J.
    Contraceptive failure in the United States. Contraception. 2004;70:89-96.)

    * The symptothermo method has a method failure rate of 2% per year.
    * The cervical mucus-only methods have a method failure rate of 3% per year.

    Sources for the above statistics:

    Watson, Dana (2005). “Why Fertility Awareness Works and the Rhythm Method Doesn’t”. The Nurtured Birth.

    Frank-Herrmann P, Freundl G, Baur S, et al. (December 1991). “Effectiveness and acceptability of the sympto-thermal method of natural family planning in Germany”. American journal of obstetrics and gynecology 165 (6 Pt 2): 2052–2054. PMID 1755469.

    Clubb EM, Pyper CM, Knight J (1991). “A pilot study on teaching natural family planning (NFP) in general practice”. Proceedings of the Conference at Georgetown University, Washington, DC.

    Frank-Herrmann P, Freundl G, Gnoth C, et al. (June-September 1997). “Natural family planning with and without barrier method use in the fertile phase: efficacy in relation to sexual behavior: a German prospective long-term study”. Advances in Contraception 13 (2-3): 179–189.

    Ecochard, R.; Pinguet, F.; Ecochard, I.; De Gouvello, R.; Guy, M.; and Huy, F. (1998) “Analysis of natural family planning failures. In 7007 cycles of use”, Fertilite Contraception Sexualite 26(4):291-6

    Hilgers T.W. and Stanford J.B. (1998) “Creighton Model NaProEducation Technology for avoiding pregnancy. Use effectiveness”, Journal of Reproductive Medicine 43(6):495-502

    Howard, M.P. and Stanford, J.B. (1999) “Pregnancy probabilities during use of the Creighton Model Fertility Care System”, Archives of Family Medicine 8(5):391-402

    Sorry for the research essay!

  5. Soler Françoise said, on February 5, 2010 at 1:37 pm

    Thank to Lissa, but please the practical effectiveness and method failure rate are not the same : the symptothermo method (double check) has a method failure rate of 0,2% or 0,3 per year. See the more recent publication of Frank Herrmann and others.
    the Human Reproduction Vol.22, No.5 pp. 1310–1319, 2007 The effectiveness of a fertility awareness based method to avoid pregnancy in relation to a couple’s sexual behaviour during the fertile time: a prospective longitudinal study (17.638 cycles of 900 couples). With the consequent use of barrier methods in the fertile phase the method failure rate was 0,6 %, and others rates with unprotected intercourses. Global effectiveness rate 1,8%
    The mucothermal method (Ecochard) is not so good, and Creighton Model requires more abstinence with a menor effectiveness that STM.
    With the best wishes

  6. Soler Françoise said, on February 5, 2010 at 1:52 pm

    I am sorry, but in the mentionned study by Lissa Frank-Herrmann P, Freundl G, Baur S, et al. (December 1991). “Effectiveness and acceptability of the sympto-thermal method of natural family planning in Germany”. American journal of obstetrics and gynecology 165 (6 Pt 2): 2052–2054. PMID 1755469.

    The practical effectiveness was 2 per cent

    Is possible for the first authoricomunicated his source to assert 25% of unplanned pregnancies?

  7. Soler Françoise said, on February 5, 2010 at 2:10 pm

    I am interested in to receive the reply
    Thank You

  8. bosch servisi said, on October 5, 2010 at 10:10 am

    Hopefully the exposure of the radical far right as a truly fringe group that could really be a danger to liberty in this country will rally the votes in upcoming elections. We can hope.

  9. cptacek said, on October 16, 2010 at 1:46 pm

    Who uses the rhythm method anymore? The Creighton model and other methods (BBT, etc) are NOT the rhythm method, as the rhythm method relies on a pattern of previous months to determine actions this month, while the newer methods rely on observations for this cycle only.

  10. françoise Soler said, on October 18, 2010 at 7:06 am

    OK cptacek
    In “The timing of the “fertile window” in the menstrual cycle: day specific etimates from a prospective study AJ Wilcox aand others in BMJ 2000; 321: 1259-62 demostrated that the supervival of the sperm in the genital area of the women when she has cervical mucus is at to 5 days. For this reason the fertile window is up to 6 days.
    Best wishes

  11. cptacek said, on October 18, 2010 at 1:26 pm

    I don’t see how your comment applies to mine at all?

  12. françoise Soler said, on October 18, 2010 at 1:55 pm

    I am Ok with your comentary cptacek with a little difference 6 days for fertile windows
    “For women not trying to get pregnant, life should be easy. Conception can only happen in the 12-24 hours after ovulation. Sure, sperm may last as many as 3-4 days in the genital tract, hanging around for the egg to arrive. But you’d think not having sex during the 4-5-day window would be sufficient to […]

  13. Harri said, on October 19, 2010 at 3:19 am

    This discussion could be very interesting. There are still some people who do not know how to observe the fertility window. The fertile days are between 8 – 12 days depending the cycle. This technique can be learned easily with the symptotehrmal method, also on sympto.org


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