Posts Tagged ‘fertile period’

The Ovulona is not another ovulation kit, my dear

October 6, 2008

@bioZhena‘s reply to Jennifer K. who wrote: How is this different from the other ovulation kits on the market today? It seems very similar to products I have seen before. QUOTE UNQUOTE

Actually, Jennifer, you are mistaken. There is no such thing available to you in the marketplace today.

This blockquote is added in April 2017

Ovulona - single slide 3-day fertile window


None of the ovulation kits – which the Ovulona™ is not – or any other fertility-status monitors on the market today have the required ability to determine fertile day 1, fertile day 2, and fertile day 3 (= ovulation, the last day of the fertile window).

All the existing techniques merely guesstimate the approach of ovulation, and none of them can detect ovulation separately from predicting it. They detect neither the first day nor the last day of your brief fertile window – so, they declare the fertile window to be wider than it actually is.

Let’s try to illustrate this with the following graphical comparison of the Ovulona 3-day fertile window versus the fuzzy and much wider, uncertain window indicated by one of the old techniques. (In this case depicted here it was the so-called Peak mucus method but LH kit and BBT yielded similarly wide and fuzzy fertile periods, that is the days on which intercourse resulted in pregnancy.)

Ovulona 3-day fertile window versus old methods' fuzzy estimation of the fertile period

Ovulona 3-day fertile window versus one of the old methods

Because in the Old Method ovulation was only guessed at, a fuzzy fertile period obtained.

Fuzzy and long. Wrong.

There is no device in the marketplace that would tell you, in plain English (or in Spanish, Chinese or maybe even in Czech!), “today is your fertile day 1” – meaning that unprotected sex today is likely to lead to pregnancy. And from our clinical trial results you will know that the pregnancy conceived on this first of the fertile days is likely to be a male fetus, a boy. We base this expectation on the results of other people’s studies, referenced below.

The rationale, briefly, is this: The male sperm live long enough to be available for fertilization when ovulation releases the ovum (egg) from the ovulating ovarian follicle. Whereas the female X-chromosome bearing spermatozoa have a chance to produce a baby girl only if intercourse takes place on the day of ovulation, because of their short lifespan. With the Ovulona, the rationale will have a chance to be tested and/or utilized in real life…

No such powerful tool out there

There is no device that would – subsequent to determining the days of the fertile window – confirm the pregnancy within a day or two. When, after ovulation on fertile day 3 (indicated in the graph here as day 0), your Ovulona would no longer register the usual follicular waves – and the device would interpret that as pregnancy detected, because that is how it works.

In gynecological convention, days of the menstrual cycle are counted from the first day of menstrual bleeding, but the researchers involved in studying the prediction of ovulation use also another counting system. In that counting system, the day of ovulation is day 0 (zero). This is to allow for comparisons of different cycles, because cycle lengths as well as the phases of the menstrual cycle vary from month to month and also, of course, from woman to woman.

Because the sperm can remain viable for several days but the egg can be fertilized only for several hours after ovulation, there are several fertile days before ovulation. Should the egg remain viable for fertilization longer than the believed 12 to 24 hours, there would be also one fertile day after the day of ovulation. Delayed ovulation will have this effect and this is discussed below. Only our menstrual cycle tracking technology can detect delayed ovulation, a very important attribute.

We believe that published evidence from clinical studies of this problem leads to the conclusion that there are only 3 days of high probability of getting pregnant, and that the ovulation day is the last day of this narrow fertile window.

3-day fertile window vs. old method e2

For more on the foundation of this hypothesis (i.e. for the working hypothesis of the 3-day fertile window), see where we show the outcome of the France et al. study of fetal gender pre-selection superimposed on the menstrual cyclic profile generated by our device in a small clinical trial. This indicates how baby gender pre-selection works or rather how it will work when the Ovulona™ is launched in the marketplace.

This is how come that, in the illustrations above including this one, the days of the fertile window are counted back from ovulation, and hence their negative signs in the graph. Day -2 on this time scale is the first day of the fertile window. It is clearly discerned in our menstrual cyclic profile signature, as shown in the first illustration of this post.

How prior art products and methods fail

If you only detect the ovulation day with your LH kit, it is too late for the previous 2 fertile days. Similarly, if you detect an elevated BBT temperature, which rises and remains elevated after ovulation, it is also too late. The timely determination of the pre-ovulation fertile days has always been THE key problem for NFP [Natural Family Planning] and generally for the Fertility Awareness Based Methods of reproductive management.

There is no device out there that would determine the only 3 days in each menstrual cycle during which – and only during which – pregnancy can result from insemination, whether natural or artificial.

The other fertility monitors – including the more recent smart phone apps – cannot detect delayed ovulation (which happens due to stress) despite the LH hormone signaling that ovulation should go ahead. Neither can the various other monitors warn you when ovulation cannot occur because of the failure of dominant follicle maturation in the present menstrual cycle.

There is no other device that would enable you to avoid the expense and hassle of trying to become pregnant with the help of the costly Artificial Reproductive Technologies when your dominant follicle maturation is not happening – which is only detectable with our folliculogenesis-tracking little device for home use.

Your gynecologist, your family doctor – or your psychiatrist if you suffer badly with PMS (diagnosed as PMDD) – does not have the benefit of the folliculogenesis cyclic profiles stored in the Ovulona memory for better diagnosis and better treatment than you can get today. They do not as yet have the benefit of systematic longitudinal recording of your menstrual cycle vital sign signatures, to facilitate better diagnosis of a health problem such as you may have.

There is no other technology that would – automatically and without bothering you at all – keep track of whether your cervical tissues are healthy, and would issue a warning only when detecting tissue aberration several months in a row – to spare you the anxieties and expenses associated with the Pap smear cervical cancer tests’ frequent false positives. Yes, this too is a functionality planned for the Ovulona in the future.

There is no technology as yet available to all women worldwide with these empowering features at a perfectly affordable cost.

oh yeah

oh yeah

Read also the 2012 article fallacy of ovulation calculators, calendars and circulating-hormone detectors.  Don’t let them lead you by the nose with likely this and probable that! You need to know for sure. Day 1, day 2, day 3. Simple.

Should you want to look deeper into this, do check out the  Home Page of bioZhena’s Weblog

Contact me via email at

Four fertility-related terms and concepts

December 13, 2007

For these and others, see the Alphabet of bioZhena at

Fertile phase or fertile window:

The days of the menstrual cycle, during which sexual intercourse or insemination can result in pregnancy. It includes several days leading up to and including ovulation. The exact number of the fertile days is not known. It is currently “officially” believed to be 6 days, although evidence shows that there are only 3 days of high probability of conception (while the other three days are likely due to inadequate methods of ovulation monitoring used in earlier studies). The unequivocal determination of the fertile window is a pivotal task for bioZhena. See also the previous post: /2007/12/03/fetal-sex-preselection-%e2%80%93-illustrated/

The fertile window is an empirical factor, which should be consistent with the fertilizable lifetimes of the gametes (the egg and the sperm). Those are also uncertain but currently accepted figures are up to 12 (or maybe 24) hours for the egg, and at most 3 days for the sperm. (These times must overlap, of course; they are not additive.)

The historically excessive length of the officially recognized and advocated fertile phase has always been due to the absence of definitive diagnostic means. Some years ago, a reviewer of a federal grant application wrote to reject the proposal on the basis that the then officially recognized required period of abstinence was about two weeks, which was and is impractical, of course…

Fertility (or Fertility Status):

The female of any mammalian species, including the human female, can conceive only during a very limited period of time (a window of only a few days, arguably 3), and only if all conditions are perfect. The fertile window occurs repeatedly at intervals that are said to be more or less regular (28 + or – 9 days or so) but their variability is substantial to the extent that planned pregnancy is a challenge. A normal healthy couple will statistically take at least 3 or 4 months to conceive, even if the concept of the fertile window is known to them. An increasing percentage of couples experience difficulties in achieving pregnancy, and reproductive specialists have found that a large percentage of women had no idea of when they could conceive.

FAM (Fertility Awareness Method):

A method of determining a woman’s fertility status through self-assessment of certain fertility signs: waking temperature (also called the basal body temperature or BBT), cervical fluid, and cervical position. While NFP users abstain, FAM users apply one of the barrier methods of contraception for vaginal intercourse during the “unsafe days” of a woman’s fertile phase. NFP stands for Natural Family Planning.


The joining of an egg and sperm. More accurately, fertilization is the union of a spermatozoal nucleus, of paternal origin, with an egg nucleus, of maternal origin, to form the primary nucleus of an embryo. It is the fusion of the hereditary material of two different sex cells, or gametes, each of which carries half the number of chromosomes typical of the species.

Although sperm can swim several millimeters per second, their trip to and through the fallopian tubes is assisted or facilitated by muscular contraction of the walls of the uterus and the tubes. There is also some evidence that the egg releases a chemical attractant for the sperm. In any case, sperm may reach the egg within 15 minutes of ejaculation. The trip is fraught with heavy mortality. An average human ejaculate contains several hundred million sperm but only a few hundred complete the journey. And of these, only one will succeed in entering the egg and fertilize it. Fertilization begins with the binding of a sperm cell to the outer coating of the egg (called the zona pellucida). Enzymes, released by the acrosome at the tip of the sperm head, digest a path through the zona and enable the sperm to enter the cytoplasm of the egg.

For fascinating details, there was once a developmental biology site (alas, no longer online) where one could see, e.g., a photo showing the “sun in the egg”: the microtubules (stained with fluorescent antibodies to tubulin) radiating from the centrosome associated with the male pronucleus and reaching towards the female pronucleus. “This vivid image conveyed the discovery of the moment at which a new life was formed. The metaphor expressed awareness that the force of natural powers was greater than the sum of two cells.”

Then, you can read up on Homunculus: Historiographic Misunderstandings of Preformationist Terminology, an essay by Clara Pinto-Correia, abstracted from her forthcoming book, The Ovary of Eve. This essay examines the association of the term “homunculus” with the “little man” that some of the leading spermists located inside the head of the spermatozoon during the rise of theories of reproduction in the seventeenth century. You can further find out that there is “a history of speculation about sex determination that views women as incomplete males… about the notion that women are almost-men whose development or evolution is truncated… how textbooks claimed that maleness means mastery, the Y-chromosome over the X, the medulla over the cortex, androgen over estrogen…”

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