Of particular importance among fertility awareness methods is the sympto-thermal method, that is, a multi-indicator method that takes into account all fertility signs identified to date. Through daily observation of changing biomarkers, it is possible to determine the most fertile time in the cycle – the so-called fertile window – and thus increase the chances of conceiving a child. It is also possible to precisely identify the infertile phases and effectively avoid an unintended conception.

For some time now, technology has also been contributing to supporting couples who use natural methods. Below are a few technological innovations that can help recognize fertility signs.

Ovulation microscopes

These are small, handy microscopes that allow the assessment of cervical mucus or saliva for changes characteristic of the most fertile days. Around the time of ovulation, these fluids display under the microscope a characteristic “fern‑like” pattern or very dense filament structures. It should be noted, however, that manufacturers market these devices primarily to users who are trying to conceive. For this purpose, their effectiveness is reported to be about 98%. The main limitations of ovulation microscopes include their restricted usefulness in the postpartum period and during breastfeeding, during hormonal therapy, and in the premenopausal period.

Device for automatic temperature measurement during sleep

This is a small device (about the size of a lighter) worn on a belt around the hips and equipped with a very thin vaginal probe that measures basal body temperature during sleep at a time pre-programmed by the user. The measurement itself takes about 5 seconds, and the device stores the most recent reading. Basal body temperature charts obtained with this device are usually more stable and may be easier to interpret.

Set for analyzing cervical mucus collected from the cervical opening

This set includes a sampler for collecting mucus from the area of the cervical opening, test tubes for analyzing the solubility of the mucus in water, and strips for assessing its pH. It is intended mainly for women who have difficulty observing cervical mucus or interpreting it. As ovulation approaches, the pH of the mucus becomes more alkaline and the time it takes to dissolve in water increases.

Ovulation tests

These are simple, easy-to-use test strips that work by detecting high concentrations of luteinizing hormone (LH) in the urine. A sudden LH surge precedes ovulation by 24–36 hours and is necessary for ovulation to occur. These tests are also intended for couples trying to conceive. They help to determine more precisely the days closest to ovulation, especially in couples with reduced fertility. Their effectiveness, as stated by manufacturers, is about 94%.

A variation of the ovulation test combines strips that detect LH and estrogen in the urine with a monitor that analyzes the data from the strips and displays the result as “fertile days” or “infertile days.”

The limitations of ovulation tests include the inability to use them in the postpartum period and during breastfeeding, in the premenopausal period, and during hormonal therapy, in cases of PCOS, and during antibiotic treatment (e.g., tetracyclines), as well as their restriction to menstrual cycles with a length of 23-35 days.

Male fertility tests

These are simple, easy‑to‑use home tests that make it possible to determine the number of sperm in a semen sample (sperm concentration per 1 ml). The result makes it possible to assess whether the count is sufficient for conception. According to manufacturers, the accuracy of these tests is about 97%.

It should be remembered that such tests cannot assess the genetic material in terms of its normal structure or progressive motility. The result may also be influenced by factors such as stress, dietary changes, intense physical exercise, high fever, ongoing medical treatment, prolonged sexual abstinence, harmful environmental factors, and chronic illnesses.

Cycle computers

These are more advanced devices equipped with an extensive built-in database of menstrual cycles and a sensor for measuring basal body temperature (BBT). They operate on the thermal method (temperature only), additionally comparing the user’s cycle with the stored database of other women’s cycles. Some types of cycle computers are based solely on the assumptions of the rhythm (calendar) method. The devices analyze the collected data and display the result as “fertile day” or “infertile day.” They allow storage of the user’s cycle data from the last 3 to 6 months. Some models generate cycle statistics and also offer certain diagnostic functions. Cycle computers require some time to gather data characteristic of a given user. According to different manufacturers, their effectiveness in predicting fertile/infertile periods ranges from 95% to 99%.

The main disadvantages of cycle computers are their relatively high price, reliance of the decision-making mechanism on average (rather than maximum) sperm survival, and the conscious or unconscious transfer of responsibility from the user to the device.

It seems that fertility awareness methods (FAM/NFP) are not yet a closed chapter. Although new methods of artificially limiting fertility continue to appear on the market, at the same time methods for increasingly precise recognition, assessment, and enhancement of fertility are also being developed.

And finally, a curiosity: tests that determine the sex of the baby in the mother’s womb have also become available.

This is a home urine test to which a reagent is added. Manufacturers claim that it is nearly 100% accurate and that reliable results can be obtained from the 14th week of pregnancy. It is worth noting that, as early as ancient Egypt, pregnant women attempted to determine the sex of their child using a urine‑based test involving grains. If barley sprouted first, a boy was expected; if wheat, a girl.