Posts Tagged ‘menstrual’

Major studies decades ago revealed variability of menstrual cycles

March 10, 2010

But people are still naïve about the basic cause of the difficulty to achieve pregnancy

Sex education at school, its quality or otherwise, is likely to have much to do with fertility problems later in life. Many women (men, too, of course) can use the  keyboard with all their fingers (as well as their thumbs!) but have poor understanding of the basic functioning of their reproductive system.

colonial classroom


That ignorance is well known, and is underlying the fertility problems. You should see the pregnancy doctors’ tweets – replying to some incredible questions, and then the talk of various mysteries!

A shining example is this tale of “mysterious conception”. For the whole story see the Alphabet of bioZhena under M, “Mysterious conceptions (OR THE NONEXISTENCE THEREOF)” on page 34 or thereabout, from which I cite:

QUOTE:  It appears that we must dwell on this topic, because of stories and notions propagated in various pertinent circles. This writing has been prompted by page 176 in the excellent 1999 book “Woman” by Nathalie Angier, where the Pulitzer laureate relates the story of the mysterious conception of her only child. Mysterious, because it occurred, she believes and makes her readers believe, outside of ovulation and of the fertile window.

The reason for this entry in the Alphabet of bioZhena is that there is NO SUCH THING AS MYSTERIOUS CONCEPTIONS, there is only lack of information, or ignorance of the facts. We might say, intellectual misconceptions lead to “mysteries” in terms of conception, of babies conceived supposedly when conception was biologically impossible, and vice versa, some women have difficulties conceiving for the same fundamental reason. We shall use Ms. Angier’s case to make this point. UNQUOTE.

To drive the point home, here is an excerpt from John J. McCarthy, Jr. and H.E. Rockette, “Prediction of ovulation with basal body temperature”, Journal of Reproductive Medicine, Volume 31 (No.8), Supplement, 742 – 747, 1986.

Referencing particularly large studies from 1967 and 1977, these BBT experts had this to say all those years ago (and never mind their “prediction” in the cited title whereas the BBT is well known to be no predictor):

QUOTE:  Cycle regularity is often assumed by both women and their physicians. The suggestion, that the BBT graph of the previous cycle can be used to identify the day of ovulation in the current cycle, requires nearly absolute cycle regularity. [However, note this:] The data collected by 1,085 women, who provided at least 6 or more charts each, were studied for cycle length variability. … The cycle length range was more than five days for 56% of the women who submitted 6 graphs, and for 75% of those with 12 graphs. … Absolute regularity was not demonstrated in as few as six cycles. Even when the cycle length that deviated the most was eliminated, less than 1% (8 of 1,085 women) had no variation in cycle length. When the number of cycles was extended to 12, no woman had variability of less than two days in cycle length. END OF QUOTE.

In real life, you realize, no cycle can be eliminated from the experience, and every day matters. Two days are very likely to make the difference between conception and the lack of it. And/or cause an unwanted pregnancy, for that matter.


Middendorf  – On the ball

The above findings are therefore the basis on which we can say quite categorically that nobody is as regular as a metronome (and nobody conceives in an anovulatory cycle), that there is no such thing as absolute regularity, whether 28 days or otherwise.

If you are in the sub-fertile category of people finding it difficult to become pregnant, you are likely to have cycle variability of more than 5 days over those months of your fruitless efforts that define your category. More likely than being one of the 0.74% of the population with no variation in cycle length, which under ideal conditions may also mean no variation in the time of ovulation. Persistent monitoring is well advised.


What is the mechanism of stress, and how does it affect reproduction?

December 27, 2007
“When pushed too far, subfertility occurs”
Here is an ad hoc selection of a few abstracts from my files on psychoneuroimmunoendocrinology papers addressing ovulation, reproduction (folliculogenesis).

Abstracts of ad hoc selected papers about stress in reproductive physiology:

What is the mechanism of stress, and how does it affect reproduction?

The first few are representative of animal work, and then several abstracts represent the literature on stress in the human female. In between, let’s display our cyclic profile data on a non-baseline menstrual cycle with delayed ovulation. This record illustrates how our OvulonaTM device can detect the effect of stress on the course of the menstrual cycle. Non-baseline refers to any real-life female with all the stressors of our daily life, no baseline simplifications of conditions such as we need to try and approach what we would call ideality (at least in physical science we would…).

Should these abstracts turn out to be too stressful, then you may perhaps enjoy better another selection I just came across, Introduction to psychoneuroendocrinology volume: is there a neurobiology of love?



possible pathway in the regulation of ovulation – stria terminalis to the amygdaloid complex in the monkey (Macaca fascicularis) – J Physiol. 1977

Characteristics of a ventral tract from the bed nucleus of the stria terminalis (BST) to the amygdaloid complex

from BST to the amygdala, and, since the neurones of BST contain estradiol, … this tract may be involved in the regulation of ovulation.


New data on serotoninergic mechanisms in ovulation in the cyclic female rat – C R Seances Soc Biol Fil. 1979

These results provide support to the specificity of action of serotonin in the control of ovulation in the cyclic rat. They also suggest an interaction of serotonin and oestrogens in this control.


the hypothalamo-pituitary-gonadal axis in the female rhesus monkey. – Ann N Y Acad Sci. 1993
inhibit the GnRH pulse generator

acute decrease in LH and FSH secretion.

This decrease in gonadotropin release may explain the deleterious effects of stress on the menstrual cycle. However, an acute decrease in gonadotropins following activation of the adrenal axis is not observed in the presence of estradiol.

Thus, during the menstrual cycle, a relative protection against the deleterious effects of acute stress may exist. How potent this protective mechanism is against repetitive stress is not known.


What is stress, and how does it affect reproduction? – Anim Reprod Sci. 2000

stressors such as milk fever or lameness increase the calving to conception interval by 13-14 days, and an extra 0.5 inseminations are required per conception.

a variety of endocrine regulatory points exist whereby stress limits the efficiency of reproduction

stressors interfere with precise timings of reproductive hormone release within the follicular phase

opioids mediate these effects

there is a level of interference by stressors at the ovary

Reproduction is such an important physiological system that animals have to ensure that they can respond to their surroundings; thus, it is advantageous to have several protein mechanisms, i.e. at higher brain, hypothalamus, pituitary and target gland levels.

However, when pushed too far, subfertility occurs.

Non-baseline cycle with delayed ovulation

…stressors interfere with precise timings…

And the stressors may even cause the Ms. to forget her daily measurement, in spite of which the pattern is discernible and interpretable in terms of “go/no go” or “safe/unsafe” as some may put it; we just say FERTILE or NOT and leave it to the user to decide… And yes, the indication of the fertile day number will also be provided.


The role of stress in female reproduction: animal and human considerations – Int J Fertil. 1990

Tonic, pulsatile gonadotropin secretion is inhibited by stress and by administered morphine, but morphine does not block the estrogen-induced preovulatory surge in primates.

Accordingly, impaired follicular development appears to be the most common cause of reproductive dysfunction attributable to stress in the human female

must take into consideration the many differences between the hormonal responses to stress in the human and laboratory animals.


Development of the hypothalamic-pituitary-ovarian axis – Ann N Y Acad Sci. 1997

Onset of puberty is associated with a greater increase in LH pulse amplitude than frequency

Only after the steep early pubertal increase in LH, ovarian steroidogenesis is activated, with increases in androgen and estrogen secretion. Under further FSH stimulation, follicular growth and maturation proceed. The first menstrual cycles are mostly anovulatory for 1 to 2 years. Luteal phase insufficiency is common the first five years after menarche.


Hypothalamo-pituitary-gonadal axis in control of female reproductive cycleIndian J Physiol Pharmacol. 2001

Gonadotropin-releasing hormone (GnRH) secretion from the hypothalamus is pivotal to the regulation of reproductive physiology in vertebrates. The characteristic periodic secretion of gonadotropin releasing hormone (GnRH) from the medial basal hypothalamus (MBH), at the rate of one pulse an hour is essential for the maintenance of the menstrual cycle. These pulses are due to oscillations in the electrical activity of the GnRH pulse generator in the MBH.

The GnRH pulse generator is under the influence of an assortment of interactions of multiple neural, hormonal and environmental inputs to the hypothalamus. Hence, a number of conditions such as stress, drug intake, exercise, sleep affect the activity of this pulse generator.

Any deviation of normal frequency results in disruption of normal cycle. The cycle can become anovulatory in the hypothalamic lesions


Influence of the ovarian cycle on the central nervous system – Ther Umsch. 2002

In general, estradiol and testosterone exert a stimulatory, progesterone an inhibitory effect on neuronal activities which are mediated by excitatory (e.g. glutamate, aspartate), and inhibitory amino acids (e.g. GABA) and neuropeptides (e.g. beta-endorphin), respectively.

The pulse amplitudes are primarily influenced by estradiol, but neuropeptide Y, neurotensin and noradrenaline contribute to their preovulatory enhancement.

Despite of this, up to 20% of ovulatory cycles do not show any rise in body temperature.

It could be demonstrated that performance on tests of articulatory and fine motor skills are enhanced in the late follicular phase as compared to the menstruation phase, while spatial ability was better during menses. Estrogens may influence mood and well-being in a favorable manner, while in predisposed women progesterone may cause symptoms of premenstrual syndrome.

Somatic complaints (back pain, abdominal pain, breast tenderness) which are highest before and during menstruation, are probably associated with a lowered pain threshold due to a fall in the beta-endorphin levels in the CNS.


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