Evidence in humans for a lingering post-orgasm prolactin cycle. (2012)

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Comments: We long ago thought that the prolactin 2-week prolactin cycle (twice daily surges) seen in rats may occur in humans .This recent study finally confirms that the cycle may occur in human females. This cycle is caused by orgasm in humans, and is the first strong evidence in humans for the post orgasm cycle we write about.


Prolactin secretory rhythm in women: immediate and long-term alterations after sexual contact.

Hum Reprod. 2012 Apr;27(4):1139-43. Epub 2012 Feb 14.

Kruger TH, Leeners B, Naegeli E, Schmidlin S, Schedlowski M, Hartmann U, Egli M.

Source

Division of Clinical Psychology, Department of Psychiatry, Social Psychiatry and Psychotherapy, Hannover Medical School, Hannover, Germany.

Abstract

BACKGROUND Prolactin (PRL) is one of the most versatile hormones in the mammalian body, affecting reproductive, sexual and other functions. In rats, mating or vaginocervical stimulation activates a characteristic PRL secretory pattern for several days, which is essential for successful reproduction. Although the underlying mechanisms appear to be different, PRL is also crucial for human fertility. We have detected a PRL increase in women induced by sexual intercourse. Extending these findings, the current study aimed at analyzing the PRL secretory rhythm after sexual contact, in order to elucidate whether human females also show long-term alterations of the PRL secretory pattern.

METHODS In a pilot study, serial blood samples were taken from women (n= 7) in mid-cycle to assess changes in PRL secretory rhythm induced by sexual intercourse, during a period of 32 h.

RESULTS Compared with control condition, sexual intercourse with orgasm induced not only the well-established immediate PRL increase of ∼300% but also an additional PRL elevation around noon of the next day (P< 0.05). These fluctuations were measured on top of the regular circadian rhythm of PRL, manifested as a surge early in the morning.

CONCLUSIONS We are able to demonstrate a long-term change in the PRL secretory rhythm after sexual intercourse with orgasm in females, suggesting memory effects. We hypothesize that the additionally secreted PRL could be beneficial for decidualization and implantation. Further studies with more participants are required to investigate in detail the implications of such effects on reproductive success in humans.

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Comments

Great Info!

That's really amazing information, Gary. Going to make me even more vigilant about avoiding O's. Please keep sharing this kind of info as you find them.

Full PDF of the post-coital symptom study

http://www.twinsuk.ac.uk/Publicatons/2011/Postcoital.pdf

Truly the pro-orgasm bias of the last half-century has kept our researchers from asking important quesitons. Finally! A step in the right direction. Of course, my take is that there is a cycle, and that its effects are so subtle in most women that it is badly underreported. The questionnaire they used here wouldn't have picked up subtleties.

The researchers here are still cautious, but here's the intro paragraph:

Postcoital psychological symptoms (PPS) is a virtually
unexplored phenomenon in female populations. Despite a
wealth of evidence from specific internet sites and forums
(e.g., www.thenakedscientist.com) suggesting that irritability,
crying and mood swings after sex seem to be
common in females and males, to date no scientific study
has tried to explore the nature of the phenomenon. In
several case reports a similar condition — post-orgasmic
illness syndrome (POIS) — has been described in men,
consisting of symptoms such as anxiety, irritability, severe
fatigue, headache (Ashby & Goldmeier, 2010; Waldinger &
Schweitzer, 2002). However, male POIS includes mental
and/or physical symptoms and seems to appear rapidly
after ejaculation whereas reports from female sufferers
describing their condition suggest that PPS can occur after
sexual intercourse, both with and without orgasm.

Because of the paucity of epidemiologic data, it is unclear
whether PPS is caused by hormonal changes during sexual
intercourse and/or after orgasm, which can lead to emotional
highs and lows, similar to pre-menstrual syndrome,
with no obvious emotional reason; or whether the symptoms
occur because of psychological reasons such as
resentment about the partner choice or feeling a low internal
locus of control (e.g., feeling trapped in an unhappy
relationship; Krueger et al., 2003; Rosenfeld et al., 2008).

In fact, both factors could be at work:

It is not
unlikely that postcoital and/or postorgasmic endocrine
alterations may cause symptoms of PPS in women, since a
substantial amount of evidence exists proving effects of
hormones on mood, depression, anxiety and so on (Dell &
Stewart, 2000; Schmidt et al., 1998). ... Apart from biological
factors, research on female sexual dysfunction (FSD) has
shown several psychological entities to correlate even
more strongly with sexual functioning. The psychosocial
risk factors affecting women’s sexual functioning are
broad and comprise interpersonal factors such as relationship
imbalances or lack of trust, and emotional difficulties,
such as stress or a history of sexual and physical abuse
(Qureshi et al., 2007; Schnarch, 1997). It is therefore not
unlikely that, similar to FSD, these psychological factors
also contribute to the development of PPS.

Some findings:

Age was found to be substantially
correlated with recent but not with persistent
PPS, with older women generally being more likely to
report PPS compared to younger women (OR 1.06, 95%
CI 1.04–1.07, OR 2.4, 95% CI 1.83–3.27, respectively). ...

A particularly strong association was
found between relationship satisfaction and recent PPS
(OR 4.49, 95% CI 4.13–4.87, p < .001). While experience
of physical abuse was associated with recent PPS (OR 1.25,
95% CI 1.02–1.34, p < .01), experience of emotional abuse
increased the odds of suffering from persistent PPS by 2.5-
fold (OR 2.53, 95% CI 2.17–2.81, p < .001).

Anxiety
sensitive women were slightly more likely to report recent
PPS (OR 1.05, 95% CI 1.02–1.08, p < .05). Contrary to the
univariate analyses, no effects of personality emotional
intelligence, or psychological conditions on recent or persistent
PPS could be observed.

The study also found moderate heritability. Interestingly, although the researchers clearly wanted to explain PPS via interpersonal problems and sexual abuse, it only explained recent symptoms. Where the symptoms were chronic, there was little evidence that interpersonal problems and sexual abuse were the explanation:

While accounting for 70% of the variance
in recent PPS, relationship satisfaction and previous
events of physical abuse only explained 10% of the variability
in persistent PPS, suggesting that there are other
unknown factors that contribute to the phenotypic
expression of persistent PPS.

In any case, the new German study, hinting that the same prolactin surges seen in female rats exist in women after sex with orgasm, points to the reality of an actual cycle. How women react to that might well be influenced by their environment/relationships as well, of course.

Also keep in mind that the results measured intercourse, but not orgasm.

We would ideally have used a more
detailed questionnaire in order to improve accuracy in
ascertaining our ‘PPS’ phenotype. Especially the time
window between cessation of coitus and occurrence of
the symptoms needs to be properly defined, as well as the
duration of the symptoms and the role of orgasm in the
development of PPS. It is important to note that our
study assessed symptoms occurring post-coitally (with or
without experienced orgasm) and not specifically after
orgasm, hence do not cover a post-orgasmic condition.

Given the hormonal changes that happen at the time of
orgasm, which tend to be different from sexual excitement,
this could be important (Exton et al., 1999;
Krueger et al., 2003).

interesting

So men can get close to orgasm without, perhaps, as much hormonal changes if at all. Women can't play as close to the fire though without getting burned. Kind of makes sense from my short experiential standpoint.

I don't think this is right

Men probably have a cycle, too, as suggested in Cupid  and The Passion Cycle

I will be writing about it again soon...ladies first! But I do believe the male and female cycles will turn out to be different, with different neuro-endocrine variables and timing. And probably no two for either sex will be identical.